Mercedes ML550 M278 Bi-Turbo V8 Engine Teardown. Unavoidable Failure?!

[@garyzhang5099]

I read it on mb forum, just want to post here so people can prevent this from happening (applicable for m276, m278, m157 owner). The oil pump on this thing is a two stage oil pump and it has a solenoid switch can switch between low pressure and normal pressure mode. (Low pressure mode is for fuel saving...) Sometimes the solenoid getting stuck because the dirt inside engine oil and the engine will stay in low oil pressure mode then this happens. Fix is quite simple and cost $0, you just unplug the plug of that solenoid from the oil pan. No CEL, no big code, the only code is a hidden code that will literally cause nothing, even the MB bulletin ask dealer don't fix this code, even if it's within warranty.

[@Hi.Al.]

Where is this solenoid and plug located exactly?

[@JustinsSupercars]

That’s not the reason why this fatal damage occurs. The coating of the cylinder walls is the problem. That’s why in 2016 these engines have been updated to steel cylinder liners without Silitec coating. Unfortunately only the 4,7 liter engine. Not the 5,5 Liter AMG engines.

[@ralph02136]

@@JustinsSupercars Definitely does help with that issue because removing the plug prevents the oil pressure from being unneccesarily lowered. Which, if lowered at that rate, can cause damage to those cylinder walls you're referring to due to lack of lubrication.

[@nicholasketcham6409]

Wheres it located

[@B020oso]

If i had that luxury car/engine i would change oil and filter every 10.000km or max.150000km

[@johnjunge6989]

I started cutting oil filters open when I changed companies and they did not do oil analysis. One thing to pass on to every one: change your 1st oil change no more than 1000 miles, every analysis that came back was laden with dirt, brass, iron and other things (all which enter during assembly and as everything wears in) and the 2nd analysis would always come back nearly immaculate! So since newer engines run tighter specs and thinner oil. Do yourself a favor, drop the oil early!

[@timbrown9731]

Yep that’s what I do…

[@Mittencarpentry]

Did 500 on my new truck for the first change.

[@Ktmfan450]

A KZbin channel called FortNine did an analysis on motorcycle manufacturers with a machine that scanned for particulates in oil using first service samples The Chinese manufacturers broke the machine from the amount of rubbish left over from machining Royal Enfield India was cleaner than every other manufacturer by multiple factors

[@RT10Viperman]

I dropped mine on my 89 L98 after the first rebuild at 400...Looked good no metal and no trash..

[@trevorus]

​@overwhammingUnless you have to drop in a new reman engine...

[@tonychavez2083]

M278 is a thing of beauty, they get close to 28+ mpg all day for a 400 hp. V8 , they just needed port injection secondary to keep inlets clean.

[@kennethwilson1140]

Cam caps integrated into the valve covers sounds just like the sort of semi-brilliant but horribly expensive idea that a German engineer would think up, there was a time when Mercedes was renown for their near bullet-proof engineering and impeccable built quality and you paid a premium price for a car that would likely last longer than you would with proper care. Now it seems like just another outright money grab based on brand snobbery.

[@Disruptedgarage]

Now they're built to a price point. Gotta cut costs somewhere to pay for all that glitzy in cabin tech.

[@warriorplutotrent3827]

Mercedes just be throwing shit together now. Bmw too. And the fanboys still think they're better than an American v8😂

[@philbrutsche8928]

I still say that the 1980s and early 1990s were the pinnacle of most German cars. Compared to current BMWs, my 1989 BMW 635CSi is as reliable as a Honda

[@geoffmorgan6059]

Crosley ran their overhead cam in the aluminum alloy cam pillow blocks back in the 1940's/50's. Crosley made no excuses, it was simply done to save costs, nothing else. No one has ever compared Crosley to Mercedes-Benz until now!

[@adotintheshark4848]

their blocks were stamped steal. Overheat one of those engines and it was curtains.@@geoffmorgan6059

[@thereve]

I like that those exhaust headers look like Fritz just beat the hell out of them with a hammer until they fit but in reality they spent countless hours of engineering and testing to get them right

[@longlivethephoenix]

I came here looking for this comment. I thought for sure the exhaust were beat to hell. Interesting that they were engineered like that!

[@KodiakWoodchuck]

Pretty sure that's a form of engineering

[@joshmanis9860]

@@KodiakWoodchuckform engineering

[@vumba1331]

Hydraulic forming.

[@brand-x7049]

You'd be amazed, and maybe a bit scared, of what they can do with computer modeling these days... o!O

[@tally5k339]

Seeing these DI only engines makes me glad that my car has dual injection. Best of both worlds for emissions, efficiency, and clean valves

[@connor3288]

The best or nothing! Funny that toyota knows better than all the other companies, they have port and direct injection. Thought i heard some of the lexus models were direct injection only but at least they learned from mistakes and fixed them going forward.

[@cckid78]

I drove a 2014 ML 550 some yrs ago..... The acceleration was to die for.. & that distronic feature phQQk'd my head up the first time I used it.......that experience caused me to buy my own, M 275 engine. Just because I luv the acceleration.

[@fscottgray9784]

I had a ML550 with this engine. It was recalled for a intake manifold within the first 2500 miles I had it. Fletcher Jones in Vegas did the replacement and screwed things up. They got some of the vacuum lines hooked up incorrect and caused the tumble flap to activate and cause lots of noise. The first time they said I put bad gas in it and charged me for the service. I did not even make it 50 miles and the sound came back again. They had it another cou-ple of weeks and said everything was fine. Again after picking it up it started making the noise again. I drove it home 600 miles and took it to my dealer in Idaho. They found the misrouted vacuum lines and I drove it for 130,000 miles of trouble free driving. Only a small leak out of the rear main seal when I traded it in.

[@nevinkuser9892]

Not bad. It shows that some technicians really have no idea what they're doing.

[@cirrusupdraft]

Literally every time Eric said “Bore score” My brain immediately autocompleted it to “Bore score and seven years ago”

[@JasonLuther1]

I like the way your brain works

[@riccocool]

Since finding kevin Samuel's I find myself asking modern women what's your bore score wh@re? I'm single.

[@markcoveryourassets]

…our founding fatherland brought forth this wee-8”

[@09corvettezr1]

I believe the mini oil pump is for scavenging oil from the turbos.

[@255Vicks]

I have a toddler that loves these videos. It has become a Sunday evening tradition. Thanks for keeping them going.

[@martin-vv9lf]

You'll have to buy him a used water pump now.

[@garynew9637]

Cool!

[@somanyteapots]

The water pump and timing parts gags are gold.

[@thelonelywolf88]

I was ctfu at the water pump bit. I love how creative he gets

[@25aspooner]

I am waiting for him to get a really old, rare engine and actually keeping one to sell.

[@russellstyles5381]

I think that he kept the one from the expensive Dodge V10. EDIT - Viper?

[@rogeralbans4082]

Somanyteapots we all need more Eric comedy!!! I think it is one of the best KZbin channels.

[@thelonelywolf88]

@@russellstyles5381 and the Prius water pump

[@tracymckinley709]

I have a '14 GL450 with this engine. I'm aware of the bore scoring, and mine does use a little bit of oil, but runs perfect, no misfires or funny business like that. I have a lift in my garage with full intention of pulling the engine whenever it decides it is time. Love the vehicle. The ONE thing that worries the hell out of me is the fact that you've now broken THREE head bolts on M278s. If I broke one that would either be a machine shop handover or a junkyard handover. I'm not even sure how I would go about extracting a broken bolt that far down in the block. When my time comes though I'm sure going to be using this video for a reference!

[@tdotw77]

You could probably get them out no problem if you took your time and did it way more slow & patiently. I think it was a GM 4.3 6 cyl that I saw disassembled that had very hard to remove head bolts. The trick was to slightly tap w\ hammer & punch and turn like a quarter turn at a time alternating hitting & turning. It's shocking the threads back a little each time so they don't stick and snap. Spraying pb blaster or whatever down the thread holes days ahead of time should help too. Also, I think once the bolt snaps off, all the tension is gone(theres no head left), so just a SHARP left hand drill will walk it right out of the recessed hole. It's not like it's rusted in there from sitting for years in the elements. 👍🏻👌🏻🛠️🔩🔧🤔🍻

[@Jellbell46]

I dont know if this works but ive been told. If you ever get a chance to try this, please do. So in this video youll notice there are usually 2 clicks and when you hear the first click, just stop. Take off the tool, and smack it with a hammer kinda hard but not too much. Then continue to take it out. Its worth a shot

[@patwheeler4940]

@@tdotw77 dead right a leftie should draw it out.

[@nnarkaj]

Try API SP oil too

[@09corvettezr1]

It’s good when the head bolts pop and crackle, but it’s bad when they snap.

[@mikefoehr235]

Just rice crispies

[@juliandrake3159]

I had a 2014 E550 Coupe that had that engine in it. Loved that car, it was fast and luxurious and it looked good.

[@camyota]

I love how symmetrical it looks!

[@ouch1011]

When I used to work for a European specialty shop, MB were my favorite to work on because, out of all the German makes, they seemed to have at least some concern for serviceability. Not anymore. With those nut holders over the exhaust manifold nuts, I cannot imagine being able to replace the turbos with the engine in the vehicle. That is a consideration because turbos on GDI engines designed for fuel economy, emissions and throttle response ALWAYS have turbo failures. Always. The turbos are always undersized (for throttle response) and also have a lava hot catalytic converter sitting next to them. With all the induction piping, even something like a belt change looks like a multi-hour job.

[@DarkAttack14]

Those issues occur on turbos for euro diesels too, having a extremely hot dpf during a regen with a Diesel oxidation catalyst close enough to bake the exhaust turbine is not very good for them. My passat TDI snapped the exhaust turbine shaft at about 140k, no more dpf to worry about though

[@vanillasound3161]

Soooo my car has the same engine. And just started missing on 1 and 2 precisely where those 2 really bad pistons are located 😂. Thanks for the video. I'm going to go cry myself to sleep now lol

[@JohnSmith-yv6eq]

Borescope time????

[@m-c-m-]

Engine Restore

[@vanillasound3161]

@@m-c-m- ya we will see. I just bought a camera to take a peek at the cylinders. Just waiting for warmer weather now.

[@vanillasound3161]

@@JohnSmith-yv6eq ya for sure. I just left it alone for the winter. We will check it out soon.

[@Azizdesign_]

How many kms?

[@330arr]

For a modern German engine, that one didn’t look too complicated. But the propensity for the head bolts to snap off is scary!

[@gorak9000]

Did you notice it was the same bolt in the same position on both sides too? Seems like a design flaw or something. That and what causes the bore score? Is that also some kind of design flaw with the casting? It seems like it could be thermal related somehow.

[@gregkrueger331]

The head bolts are an issue with all mercedes v8’s. Most everyone that i know, including myself has had head studs installed in the place of the bolts.

[@jtjones4727]

@@gorak9000 I think a big part of that scoring is from carbon build up on and around the pistons and combustion chambers. I think it's not a coincidence that engine is direct injection. A lot of the carbon buildup gets squished around by the small piston to valve clearance, including around the sides and skirt, the only other thing I can think of that would cause that type of damage is piston slap.

[@baasbowing]

How would you remove the broken head bolts??

[@krisone63]

? that doesn't happen...

[@adonishebert6596]

I worked on MB from 1973 until 2007 when I switched to semiconductor FAB work. I am SOOOO happy I dont have to deal with that junk anymore. The factory rep told me it was a high tech rocket that couldnt get off the lot,he was right. I ma making more now than I ever did at a dealership,and I go home clean.

[@mikefoehr235]

German cars=junk. Toyota and Lexus showed up the krauts

[@narcissistinjurygiver2932]

i worked for mb from 95 to 08. so glad to get the hell out of the dealership. what a horrible company to work for.

[@lka1988]

Hey, i did something pretty similar! Worked in auto shops for a decade, then moved to semiconductors. Been to a few fabs now, very interesting career.

[@druklk42]

You should show us how do you get a broken bolt like that one. Your videos are great.

[@brianallen9810]

You don't, besides the block is wasted. You can't bore it oversize, it's got Nikasil coated bore.

[@connor3288]

​@@brianallen9810You can sleeve it i think. I believe Taso mercedes guy has video on it.

[@EJBert]

I was wondering the same. Jeez breaking head bolts like that is crazy!@@brianallen9810

[@windward2818]

The amount of deposits on the back of the valves is just incredible. In flowing heads that type of restriction would be catastrophic for a naturally aspirated engine. Since this is a turbo perhaps it is not as bad. I was also shocked that the oil pump was a vane type pump. The flow and pressure requirement must be rather large to require a vane approach.

[@pocketpc_]

Those twin turbos are probably pretty thirsty as far as oil is concerned.

[@ZeDestructor00]

Merc has had a fairly strong preference for vane-style oil pumps for quite a while, even on very low-power (by their standards) engines.

Is a direct injection problem, happens to all.

[@Technotranceism]

It's highly detrimental in forced induction. Carbon coking is a huge problem with GDI engines, and one of the reasons why some companies opted for a multi injection system.

[@connor3288]

Junk on the valves will cause airflow issues, whether na or boosted to 20psi.

[@jacobcashen1301]

Its always cool to see you teardown Benz engines as i work at a Mercedes dealer. Seeing things than come in day to day but fully torn down is super neat. If possible, an M274, M260, or an M132 would be some interesting ones to teardown. Much love, Eric!

[@nevinkuser9892]

Everything should be torn down in order to fix it correctly. It is indeed the best way to make any machine run like new.

[@scooterwoodley195]

Brett is quite the thespian. 👏 Taryl Dactyl and his crew at the Grass Rats Garage are still number #1 but you guys are making a strong push.

[@amaresch66]

275K subscribers, you must be doing something right. I wonder how many of us are not mechanics but are still fascinated by these teardowns? I saw the box of snack packs in the background and for some reason instantly wanted one, lol.

[@capn_shawn]

Great Video as always! My last Mercedes was a CL55 with a 113K motor that made it > 250K Miles with no issues. Now I have an M278 and am on my 4th set of turbo coolant pipes, bad tensioners, bad cam adjusters, constant check-engine light, leaking intercooler circuit, bad heater circuit, oil in the ECU and more antifreeze leaks than I care to list. I will not be giving the hot-vee engines a chance.

[@diablocls55]

M113k for life for me. I stay away from these newer twin turbo V8s. I’d even take an M156 over one of these all day

[@E39M5SPEED]

113 was the best motor. I’ve had several AMGs but by far my favorite was my good old trusty C55 with NA M113. Legendary engine. Simple. Robust. Easy to work on.

[@E39M5SPEED]

I used to do turbo Coolant lines on these all day every day. They would leak at the plastic fittings by the water pump. Those bolts at the turbos holding them were a major pain to get to while engine was in the car. Many many bruised knuckles. I don’t miss that at all.

[@capn_shawn]

@@E39M5SPEED If ever greeted with another to work on, a sharp knife will cut the heat shield from the wheel well. Peel back the heat shield and the turbo is right there. This makes this job a billion percent easier. PS: my latest issue is camshaft angle pickup flag has slipped (you can physically see the error if you remove both intake cam sensors and spin the motor). I cannot stomach the idea of removing the valve cover(s).

[@E39M5SPEED]

@@capn_shawn yeah but then I don’t want to give back customer with destroyed heat shields.

[@astonmartinvee8]

I had a 2012 CLS500 (AU) with the M278, no problems, but sold at about 60K miles. We now have a 2015 CLS63S with the M157. One potential issue is oil wicking up from the cam sensors, solved by checking and replacing them. Its done about 45k miles. No issues as yet. No tuning, no thrashing until warmed up. However, what a complex engine. They do also get very warm with the two turbos. You'd think manufacturers might have made a little progress in design and maintainability by now. That's the key insight from this.

[@willgallatin2802]

Steel sleeves, and pistons would do wonders to correct this mess. I still prefer older Iron. It's just simpler to care for.

[@AC-io8qs]

Thanks for doing a teardown on a M278! These engines are known for premature piston/bore wear, but only in certain VIN/Engine number ranges. Only some have this issue from 2014+.

[@AZMTB]

Any idea if this affects 2017's? We have a GLS 550 with this engine. Currently has 50k miles.

[@WRCWRX]

I’ve seen all years M278’s have premature wear on cylinder bore, camshaft/ rocker arm & rod bearing’s. Not too mention the issues of camshaft position sensors pumping oil into the engine wire harness. These engines are junk by 90k. Replacement cost is $34k.

[@AC-io8qs]

@@WRCWRX Well, while I don't like to argue online, my M278 is sitting at 112k and only burns about 1qt every 6k (my OCI) and has been doing that since 20k miles. But I have an extended warranty, just in case.

[@Der_Ingenieur]

⁠@@AZMTBMB revised the block in early CY 2015 with different bore surface material. Your 2017 should be fine.

[@ericwheatley8897]

I believe silitec cylinder wall linings were in the earlier versions, then they went to nanoslide wall linings.

[@KevinMiller-lh9ur]

Was expecting to see the water pump launched into the scrap bin and then to see the box being run over by the truck was even better. 😂

[@concernedcitizen780]

No love for water pumps….

[@systemsbroken]

Do you know how many "Car Poor" ghetto dwellers in Salvage Title "Benz" cars who would love to have that perfectly functional water pump? Seriously, how are they supposed to go visit their kids (once the talk show validates paternity) if they can not afford a water pump? @@concernedcitizen780

[@janlombard6712]

That pump is way over- engineered and expensive. He kept it for resell

[@modified15r]

I had a E550 with this engine. They seem way more powerful than the 402HP there rated for. Car and driver ran a 12.8 @118 mph 1/4 mile in a 2012 E550 (4400 LB car.) It's all about the torque.

[@ralph02136]

they make around 440-450 crank hp

[@marvinmcconoughey3547]

The same appearing engine was rated higher--449 HP if my memory serves-- in the S class. But I agree, it feels enormously powerful with fabulous low end torque. It revs very well, but very seldom needs to.

[@kevin9c1]

Good to see the Garrett/Honeywell turbos hang in there. They have a good reputation and seem to be better than pretty much all of the competition in terms of longevity.

[@mikeissweet]

I have this engine with a tune on it and 225,000 miles. Original turbos still holding up perfect

[@NickeryNelson]

@@mikeissweet What year is your engine? Also, what type of oil do you use? Thanks!

[@mikeissweet]

@NickeryNelson 2013. Was still running perfectly when it was rear-ended recently with 235,000 miles Edit: Mobile 1 European blend 0w-40 every 5k miles

[@NickeryNelson]

@@mikeissweet Wow! So sorry to hear this. Hope you can find another one in good shape. Thanks for the info.

[@mikeissweet]

@NickeryNelson Yep, I was devastated. Wound up with 2020 GLC 43 AMG. Pretty fun but only a 6 cylinder

[@edenilsonrivas7900]

More mercedes engines !!! Please ! Love seeing someone else other than me do this lol . Hopefully you get a m274? As a mercedes tech overall these are pretty solid there were a decent amount of bad ones but mb is taking care of it surprisingly, check heads and exhaust valves ! Best guess is burnt valve seat or valve and still drove it with the misfire caused further damage leading to scoring .

[@gorak9000]

What actually causes the bore scoring? How do you get sideways forces to push the piston into the bores? Or is it thermal somehow? Like the bores constrict in that direction when it gets hot?? Is it a design flaw of some kind?

[@poshweevil2960]

M113!

[@BurnsRubber]

@@gorak9000Wear metals in oil likely caused the scoring.

[@kafklatsch3198]

But its almost every cylinder... in the same area...i hear what you are saying, but as an engineer, for the result of the burnt valve to be consistent - without 6 cylinders worth of burnt valves (unlikely), there is more likely a design flaw Or weakness. .... whereas less then perfect maintenace .. or less than perfect manufacturing process leads to failure of the weak link... cylinder walls in a very specific area...and the resultant fragment eventually taking the engine out..

[@diablocls55]

I’m hoping to see him tear down an M119, M113 or M113k

[@gentjim5007]

Never ceases to amaze me how different manufacturers build different engines to solve the same problem. The contrast between this merc and an ls3 is huge, but basically put up the same performance numbers. I'll take simple over complex any day 😊

[@moneyshifters]

It's not all performance. All manufacturers and their RND is working with the same tools but with different goals. This motor happens to be the answer to the question that no car enthusiast will ever ask (efficiency, economy, emissions, smooth power etc)

[@juggsauce]

Yeah when he mentioned the horsepower I was blown away. Funny thing is that the ls3 or lt1 will burn less fuel doing it. It's hard to appreciate any advantage to this thing.

[@pearldrums92]

I would imagine with simple tuning this motor would have a much higher headroom in terms of power. I own an Ls3 powered car and I love it- but again I’d assume this thing could make 550+ with tuning and fuel. Ls3 makes 450 to the crank maybe with fuel and tuning.

[@moneyshifters]

@@pearldrums92 yeah and this thing is probably super efficient too.

[@hotdog9262]

@@pearldrums92 and it probably makes more power then they will admit. power is expensive and kill sales and profit

[@mafuyu4698]

Perfect way to cap off my night with one of these uploads. Thanks man.

[@Scooter-dm3qo]

In regards to the head bolts, Welcome to Torque to Yield fasteners. When you torque a fastener to it's Yield Point you have insured that fastener has no "reserve strength" and a small additional load can snap it like a dry twig.

[@billincolumbia]

Yeah, I was wondering if that was what was going on. Thanks for confirming.

[@glasser2819]

they need to be nearly as strong as the aluminum heads. So a soft steel to prevent stripping threads

[@allenl9031]

Perhaps the leaf was the root cause of the oiling problem, clogging the branches to the bearings and rings. Tree rings.

[@dustcommander100]

I think you're barking up the wrong tree.....

[@joshmanis9860]

My dads Saturn has eaten many a leaf and is still doin just fine at 445k

[@jameshodgson3758]

To avoid breaking the head bolts you may want to try this. When you hear the first pop quit turning. Remove your socket and strike the bolt rather hard on the head with a drift or directly with a hammer. Put the socket back on and remove the bolt.

[@edifyguy]

That's brilliant.

[@valpanig]

who taught you these skills, they are unbelievable !

[@kevincurry4735]

Good evening Eric. Just watching you try to turn over the engine is getting me hopeful for some malice. What drastically deed will you do tonight to the poor water pump? I just cannot wait. 😆

[@davidcustard9311]

Thank you for all your great videos. I watch more KZbin then I do regular TV. I've learned a lot about different engines. Love it!!

[@jacquesc3166]

Those intake valves..... it's like DI problems were built into the ownership experience. MPI on Mercs from the early 2000's was great, the old 5 speed auto was great too. It's like E500's might outlive E550's altogether.

[@dishsoap1]

Now imagine having a KIA direct injected engine. lol

[@erictyppo5850]

NA 550s last a long time if they're taken care of. The M273 is an excellent motor. Outside of very early production that had an issue with a timing chain idler, they don't have any big issues and make significantly more power than M113s. Good old port injection too so no intake valve issues.

[@diablocls55]

I can’t count how many E500s I’ve seen with 200k+ miles my own included. My M273 made it over 200k but that was also a NA engine. I’m seeing these twin turbo ones blowing up left and right lately

[@nnarkaj]

@@diablocls55I had 300k and still going strong before I bought this same m278..

[@jackparker5971]

I work at an independent mercedes shop and we regularly see a couple of these 278 engines come in with a customer complaint of knocking noise, you can hear them knock from underneath the car and then run a compression test using the mercedes scan tool and find them running low on compression, have seen a couple with this knocking noise running for 30k miles after we told them the cylinder walls are scored and needed an engine, so far i’ve only seen one engine that was scored so bad it was a dead misfire 28:18

[@aimless-drifter]

what design flaw would cause cylinder scoring? Are the skirts too short?

[@KR-hg8be]

​@@aimless-driftergerman engineering.

[@haydenh6339]

@@aimless-drifterprobably overheated.

[@warriorplutotrent3827]

​@@haydenh6339on an 30k mile engine?😂

[@haydenh6339]

@@warriorplutotrent3827 who said it had 30k? Mileage unknown in video. This happens often when the plastic turbo lines break and dumb customers keeps driving it.

[@darrininverarity4297]

I would redesign some of this engine,change that direct injection back to a port type or a combination of both types of injection,the valve cover/cam journal needs more webbing with oil galleries and maybe brass guides on the floating lands and this could be a very good V8 with double overhead cam valve train and twin turbos that with a non Cletus McFarland tune this thing would provide huge power with high mileage reliability.Breaker bar the head bolts loose,then tighten them back down and by the time you get to that head bolts that breaks,it won’t. Great video thanks for sharing.

[@TheBandit7613]

I'm not impressed. Only 400 hp with twin turbos, DOHC, direct injection ect? My simple 351 Cleveland powered Mustang Mach one has 330 hp with pushrods and a simple Motorcraft 4V. Ridiculous. And my Mustang still runs after 50+ years and 1/4 the parts. A modern lawnmower has more tech than the Cleveland.

[@MrPabsUk]

@@TheBandit7613 And do you think your 351 would meet any global emissions laws of the last 30 years?

[@TheBandit7613]

@@MrPabsUk Not late model emissions. I don't think 73' needs emissions.

[@RT-mv7df]

Your head bolt suggestion is a pro trick!!! Breaking the outer head bolts starts to put tension on the remaining inner ones so that it takes more torque to turn them.

[@harryh5620]

damned that thing is a *beast*. Imagine working on that in the car! And what you were talking about at about 8:50 is called "Safety Wire" - something all us aircraft wrenches know all too well.

[@mitreswell]

Lockwire

[@Z-Man1973]

Hi Eric, I always enjoy your videos, whether they be engine teardowns, working on your own cars, or trying to get vehicles running that you just brought onto the yard. I have learned a wealth of information about internal combustion engines from your teardowns. I've always know the importance of regular maintenance on vehicles, its fascinating to see how the lack of regular maintenance can destroy a high quality, reliable and well engineered engine. One thing I'd love to see is a compilation video of cracking cam-cap bolts, rod bolts, head bolts, and main bearing bolts. I absolutely love the sounds and I find them strangely soothing. But I'm just kind of a nut-case that way. Keep providing this fantastic content. The great thing is that it seems there's no shortage of source material!!

[@angusjoejohnson1036]

The reason these engines fail imo is heat soak of the intercooler and crazy intake air temperatures causing pre ignition / detonation. I logged the iat temps with an auto meter dash link. The intake temps stay within 20 degrees of ambient if you get in and don't stop. If you stop and idle for awhile or go to lunch etc, the iat temps are 120-130 or more. They are that high on a 100 degree day no matter what. that's too high for these engines. I'm splitting the intercooler from radiator and installing a massive front mount heat exchanger, high flow pump, and one step colder ngk plugs. I'll repost my results. I just started and should be done this weekend.

[@waynekingston7772]

Very interested to hear the results!

[@glennk1931]

Another interesting video. Sad that these engines have such terrible issues. They are very expensive.

[@krisone63]

They don't have this issue, it's an anomaly, if you want catastrophic failures watch BMW engine tear downs, M5's self-destructed on a regular basis.

[@shaggyduder]

Most issues arise due to lack of maintenance, a lot of people buy these cars, then realize they can't afford the insurance, the note, AND the upkeep, guess which gets overlooked.

[@apb1236]

@@shaggyduderthis engine looks relatively low mile considering how clean the turbos are. Maintenance or no maintenance, most modern German engines are disposable garbage. Best just to lease and toss…

[@e.e9331]

These engines actually very very reliable except few small but rtareded. The main problem with them is 1. extended oil change intervals, this alone creates so many of M278/M157s problems its mind boggling.

[@aserta]

Lack of maintenance (a common garden variety issue in some parts of the world) is the issue (terrible) here. Feed the engine right, and it's gonna last.

[@bladerunner5810]

This makes me appreciate the simplicity of old school American V-8 engines. I started working on Chevy small block engines for my Dad when I was ten years old in 1958. Then as now, if people only changed the oil and all the filters at proper intervals along with the coolant every two or three years they would likely never have a problem. Everything on those things was readily accessible and I do not recall water pumps being an integral part of the block in most of them. Just saying.

[@davidandrew1078]

Looks like a Tank Engine.

[@edgepitts]

Gotta love the Germans!

[@robertwest3093]

What a coincidence! That's the first thought that entered my mind.

[@abeodez751]

Merc does make engines for big farm equipment like class corn cutting chopper with over 800hp and over 2000tq And some Lori too

[@josephd.4890]

Guess you've never done a water pump on a three point eight nineteen eighty eight camaro, cause they have three Different bolt sizes and two are metric and one is standard

[@123yrmama]

My God 400 hp for that monstrosity ?? That not much power for all that shi*.

[@dkjens0705]

Many modern engines use an alusil block where a cylinder sleeve is not necessary. For an aluminum piston to run in a cylinder like that, it needs an iron coating on the piston skirts. Depending on many factors such as design, driving habits and oil quality/supply especially can determine how fast that iron skirt wear down and as soon as that iron coating wears down, you have bore scoring. I've seen many many Porsche m96 and m97.1 engines, especially the 3.6 and 3.8S engines with this problem. If you want to spend an extra $5,000 on your m96/m97.1 engine rebuild and even increase its size by 200cc, you can have the block sleeved and use forged race pistons. You can also increase the size by 400cc but then tuning is needed and adds another $2,000. The end result with a sleeved engine is a much better, more reliable and much longer lasting engine.

[@edifyguy]

Just a few thoughts on this, other than that I think the engine looks really cool fully dressed. :) 1. I'm reasonably sure that the back 2 cylinders had cleaner valves than the rest because the valve guides were leaking, and the small amount of oil flushing the area kept the valves cleaner and the spark plugs dirtier. 2. The reason the crank and cams were OK even though there was metal in the oil was that the metal was all aluminum with no steel in it; aluminum is so much softer than steel that it can't scratch it very effectively. Add in the very small particle size and its more of a polish than an abrasive. 3. I strongly believe this engine was overheated somehow. Not apocalyptically, but enough to distort the cylinders and pistons so they didn't have the clearances they need. Also enough to get the cylinder head bolts really good and stuck. The idea expressed elsewhere in this comments section to give the bolts a good whack with a hammer and punch between the first click and the second groan (to relieve some of the internal tension) is actually brilliant.

[@bigwater52]

I’m 99.0% sure this engine is dead from a tuner/performance aspect. This engine was prolly tuned by someone who didn’t know wtf they was doing, and prolly had the pop/crackle tune. Definitely looks like a slightly lean/detonation ordeal, somthing in the tune was beating the piston. Have seen this in a few of these engines, and a lot of the amg 63s that have had the turbo upgrade and tune! Have never seen a Benz tuned/upgraded turbo engine come in with these type failures. We build these bastards, and do some crazy stuff with these things. And they make crazy power, reliably if your bank accounts big enough

[@bigwater52]

The m156 6.2 v8 are the ones with lots of issues! But we bullet proof these things, with good custom made in-house billet Replacemnets, my personal, daily driver is a rods piston, m156 with 60k miles on a inhouse built engine. Around the 700ish wheel hp

[@connor3288]

​​@@bigwater52What is your shop, any build thread on your m156? I have researched m156 and m157, I think i want a w212 m156 car. Yes they have head bolts, vvt wear, cam and bucket wear, intake leak. But doesn't look so bad compared to m157 plastic parts, cylinder scoring, and DI issues/costs. What did you do to your m156? They're beastly stock, around 500hp, i heard sls m159 is over 600hp na. The weistec superchargers look sweet.

[@bicylindrico]

@@bigwater52 Doubtful in an ML550. My guess is excessive idling in cold climate. The previous M273 had the same issue. MB engines are total garbage anymore and good for 100k tops before the problems are likely to start.

[@johntaylor1947]

i adjusted the valve lash on my 1982 two-cylinder diesel tractor today. it is ridiculously simple, and that engine is ridiculously complex. i will stay with my two banger..

[@vumba1331]

Is it a SAME Delfino? We had one a few years back, 2 cylinder, 2 litre air cooled, easy to eork on as you've said and absolutely bullet proof! Bit noisy though....

[@brentdoncliff2845]

It'd be interesting to put a torque wrench on the head bolts and see how tight they are.

[@brianallen9810]

They snap off because they didn't use anti-seize at the factory ( they're threaded into aluminium ) or have them cadmium plated.

[@tnesp]

Pretty steady quality, too. On both heads the bolt that snaps is the same position and seems to snap from the same spot.

[@connor3288]

Breakaway torque and bolt tension aren't always related. Any fastener with thread lock, rust, galled threads or galvanic corrosion will have much higher breakaway torque than normal.

[@willgallatin2802]

Wet timing, and oil belts rank pretty high. However the idjiteer whom started putting the starter under the intake manifold is a real show stopper. Just behind putting a turbo under the intake.

[@Flies2FLL]

Bore scoring is an issue on some modern Porsche's when the engine is driven hard while still COLD. Great video!

[@rodgood]

yes you hit the nail on the head .

[@bonda_racing3579]

@@rodgoodahh really that was a theory I thought of. Owners just starting and leaving without warming up first.

[@michaelhughes7513]

From what I've seen, starting and leaving is preferred, as driving heats up the oil and coolant faster than letting it idle. You just don't want to start it, drive off, and immediately romp on it while still cold.

[@gchampi2]

@@michaelhughes7513 Yup. Drive gently, staying below 3,000rpm until the engine is fully up to temperature and all the engine tolerances are as they were intended. THEN you can hoon it. Showing off from cold kills more high performance engines than anything else - maybe not immediately, but it shortens their service life dramatically. Driving like a granny may not be as glamorous as leaving with a roar of power & a cloud of tire smoke, but it's a heckuvalot cheaper in the long run.

[@c-teamtrading9690]

Btw for all the Merc fans of this motor. Liqui Moly has a port cleaner you use once very 20 000 km (every service) that keeps those valves clean 😉😉

[@NickeryNelson]

How does port cleaner work on direct injection engines?

[@noonehere1793]

I had the earlier ml 55 amg…..a spring broke on the throttle body……it started accelerating without control. I was just reaching to pop it into neutral and blow the engine when it finally dropped back to idle. Off to the Mercedes dealer i went after i discovered what the problem was. $900 dollars later i picked up the “repaired” car. Opened the hood, checked the spring (still broken) and went back in to deal with them……sold the car that week. It was my LAST MERCEDES. What can of worms those things are.

[@seinundzeiten]

they sound like horrible cars

[@papapetad]

What an absolute mess of a thing to work on. The motor itself actually looks like a very well built unit but what a packaging nightmare. GDI and broken head bolts just adds to the nightmare. This is the kind of thing that keeps me away from new cars. Even small engines look like overly complicated messes and the theme extends to the useless electronic gadgets lathered throughout. These vids are an excellent way to learn what to stay away from. Thank you for taking the time to do it.

[@hangman396]

Another Great tear down Eric... Please continue

[@scottpecora371]

Ive a 1995 S320, came to me with 130k, for free, had been garaged and loved. Beautiful body style. Replaced a water pump, a tune up and had the tranny serviced, replaced the tires and front brakes and belts. Finally parked it d/t too many vacume leaks, weird electrical. Tons of electrical shit going wrong, engine though bullet proof. Never had a concern about the engine. Got its best milage at 75-80mph and drove Beautiful. A Stuttgart beauty!

[@WilliamSudek]

The part of the oil pump that you didn't know what it was, is the scavenge pump for the turbo oil return.

[@JohnSmith-yv6eq]

So sucking in the foamy turbo exit oil and squirting it where?... onto the windage tray?....... to lose the entrained air before it circulates back to the main pump via the sump?

[@pobinr]

I just bought an R231 SL 500 (SL550 in USA) with this engine. Amazing torque. It flies. I love it. Hopefully won't need this done.

[@legionofanon]

I noticed you didnt throw the water pump intitionally, and you almost had me when you said you sold it. Your water pumnp skits are getting better and better

[@inoe6475]

yeah yeah !!!!

[@jeffryblackmon4846]

Another engine that is too complicated IMHO. Great job on the teardown. Your closing segment- priceless.

[@Darbman62]

All engines are too complicated these days. Need to get all the emissions crap off them and they would be much better.

[@kiidedgar9951]

I’m no mechanic but love watching the teardowns also was wondering if maybe it would be a nice detail if u added a picture of how these cars look when talking about the engines

[@johncoops6897]

Each engine could be used in 10, 20 or even more models of car across numerous years. How many pictures would you want?

[@l3LaZ3ful]

​@@johncoops6897 He always states what vehicle the specific engine he's tearing down comes from, so all he would have to do is show that 1 vehicle. That's what the person above is asking.

[@johncoops6897]

@@l3LaZ3ful - He says it came out of a ML550 and this engine is also used in GL, S, E, CL, CLS and M series. Basically, every single Merc model range could have this engine in it. They were used in models from 2010 to 2020, so over 10 years that is a pretty huge range of vehicles. If people really wanted to know, I guess it would be very easy to just search Google Images if they wanted to know what a Mercedes vehicle looks like. I'd reckon that most people (especially those watching a car-related video) would know what a Mercedes ML series looks like, wouldn't they? . Yeah, I guess Eric could try to find a royalty-free high-res photo of an example of one of the vehicles to edit into the video. But in my opinion it seems like a bit of a waste of his time, especially considering that each engine is used in so many different cars anyway.

[@elia2649]

Just Google it bro

[@kafklatsch3198]

I agree... a pic n pic for a couple seconds would be just a extra layer of goodness for the channel... great suggestion IMO

[@gchampi2]

Nice to see the most important tool of any auto shop on prominent display in the background of the opening shots. A Fire Extinguisher should always be to hand when there's fuel and potential ignition sources in the same area. You'd be surprised how many shops fail this. Sure, they have one in the shop, but its "somewhere". Top tip, if it takes more than three steps to reach your Extinguisher, its TOO FAR AWAY...

[@stevenbrowningsr1144]

Considering both broken head bolts being in the same position, I wonder if that is a problem with the automated torque tool used to make up the head bolts in manufacturing?

[@gorak9000]

Yeah, I noticed that too - same bolt in same position on both sides... really makes you go "hmmmm....."

[@BigUriel]

I think it was a temperature issue. All the scored cylinders are in the middle and the outside cylinders are fine, both broken bolts also in the middle cylinders. Most likely this engine ran hot, really hot, from lack of oil or coolant or just being redlined hard all the time. The middle pistons overheated, expanded too much and damaged the bores, the middle bolts were stretched. The cylinders at each end cool faster so they survived.

[@MarekLewandowski_EE]

These were the bolts that sit behind the exhaust side of the turbos. So that area is simply hotter, than any other place.

[@edifyguy]

@@BigUriel I felt like this engine suffered heat issues, too.

[@alexanderjones6383]

Those hydro formed manifolds are beautiful.

[@korn111685]

What’s crazy is if the goal is 400hp the design of this engine is ridiculous compared to other engines with 400hp, I’m thinking of some pushrod v8s.

[@waverleyjournalise5757]

The 4.7 is detuned compared to the 5.5 which shares virtually everything and makes about 585hp.

[@sourdojack]

A tune and high flow cats nets about 750hp from these engines.

[@diablocls55]

Makes more than that. Mercedes has a habit of underrating the power output of their V8s

[@garyzhang5099]

@@waverleyjournalise5757sadly that 5.5 block is not very strong. 4.7 is a bit stronger but not much.

[@waverleyjournalise5757]

@@garyzhang5099 it's the same block

[@cam32112]

Another great video Eric. The water pump bit at end was pure frosting. It never gets old!

[@zf9903]

Those ain’t valve covers. Those are Cylinder Heads Part Two: Electric Boogaloos. Edit: someone please bring intentionally rebuildable components back. Let me FIX my parts instead of forcing me to REPLACE my parts.

[@robertcochran7103]

Thank you for this really interesting video. The engines seem so beautiful to look at, but the bore score problem is so ugly.

[@PineHollowAutoDiagnostics]

OMG that head bolt sequence was hilarious...good good good BAD good xD Looks like they designed that block to be non-serviceable since 1 head bolt per side snaps deep down in the hole guaranteed!

[@I_Do_Cars]

The bolts are bad, but you'd have to resleeve the engine, that would cost a fortune... not that the replacement engines don't lol

[@PineHollowAutoDiagnostics]

@@I_Do_Cars It's crazy that bore scoring led to this engine failure...would think they perfected cylinder and piston basic design decades ago...especially on something so high-performance and expensive lol!

[@JohnSmith-yv6eq]

Apparently they went to iron spray cylinder linings in 2015@@PineHollowAutoDiagnostics

[@mikeissweet]

Hah yes!! My engine ❤ Edit: Mine has over 225k miles and original everything (except for a few coils and plugs) and she burns zero oil and no sparkles, for those who are interested. I'll poke the borescope into a couple cylinders and update ya'll on the scoring issue, if I remember.

[@ingresswizard9044]

What year? Mercedes changed the bore slide tech in 2015. Also check your Cam position Sensor and Cam adjuster plugs for oil. If you find it you must replace those and buy the harness extensions to prevent oil from wicking up into your ecu and destroying it.

[@mikeissweet]

@ingresswizard9044 2013. And yes, the cam position sensors are full of oil, hah. And I've noticed a little oil on the ecu pins. Thanks for the heads up, though! We're now past 230k miles and going strong 💪

[@TestECull]

9:03 The easiest way to get that off is to just shove the impact on and rattle the nuts out. It looks like the locking sheet steel is too thin to do anything useful and the impact won't even notice it.

[@nevadacoyote]

I love your channel. At some point in the future can you spend a minute or two on how a high pressure fuel pump works. I can't quite figure it out. Many thanks for your love of this channel

[@leddygee1896]

The more complicated the engine, the more prone they are to Failure… Simplicity over complexity always wins!

[@chandraprakashvihtavuori2562]

In this case, the problem is that Mercedes ditched cast iron sleeves from their aluminium block, which basically makes bore scoring inevitable at 60,000 miles. It looks like a good engine otherwise.

[@RexNathanChan]

Reading online, the M276/278/157 are supposed to be reliable, so far...

[@BloodlineMedia]

Thank you so much for this video - I have had eight Benzes and my GL450 2014 is easily my least favorite. This engine is so weird and designed to fail it gives me anxiety. I replaced the turbo cooler lines with the engine in the car and it took forever. Also respect the extensive editing this video must have taken.

[@chris3407]

Great video! Just curious, how long did this video take you to film and complete this tear down?

[@johnforster5312]

Every time I watch one of these videos and think about doing any amount of this work with the engine in the car, it makes me glad I decided to work on aircraft for a living and not cars!

[@Mike_Hoffmann]

Re-leaf valve perhaps?

[@tomhanna2714]

I knew you were up to something snaky when you skipped the water pump. And we were not disappointed. But wait, there’s more! Did I see you throw away a CHAIN? Say it ain’t so!

[@MrZerocool5000]

i think the failure in my humble opinion just like other german engines is the coating that they used (maybe still using) in the cylinder liners

[@brendans1156]

I was confused when I didn’t see the water pump go flying when it was removed, but I’m glad I stuck around till the end😂

[@derekfelber743]

Every time you tear down one of these modern engines I just cant understand why we need things so complicated. Are these new cars really worth owning knowing that if your engine fails its gunna cost you 10k?! Just seems like a stressful headache

[@matt.604]

I guess that's how engineers have gotten 300, 400, 500, ... horsepower out of car engines over the last few decades.

[@derekfelber743]

@@matt.604 yea but you cant tell me a well built pushrod v8 with some spooly bois strapped to the sides wouldn’t do that?? Lol

[@KR-hg8be]

​​@@derekfelber743 right, 6.0ls engines make 400hp all day long reliably for hundreds of thousands of miles. Throw twin turbos on one an your looking at 4 digit hp possibilities.

[@garynew9637]

​@KR-i6 ford engine from australia can make 700 hp on stock internals, 2,200 on high spec internals. Barra engine.hg8be

[@sourdojack]

I've seen dozens of these engines with wasted piston rings, usually just on one bank (if you catch it early). They all had one thing in common, oil leaked in the harness and oxygen sensors from the camshaft sensors. I suspect the oil throws off the O2 sensor readings and causes a bank to run lean. I would love for someone to prove or disprove this theory.

[@jeremysmith1777]

We do miss Safety Tote. It's been a hot minute since he's been needed.

[@litz13]

Eric - This is a GL Mercedes. If you can afford the car, you don't repair the engine, you just buy a new engine.

[@worldofai-games1036]

Even better, you buy another Mercedes… I’ve seen people trade in 5 year old Mercedes.

[@thomasdeir6212]

What a beast of an engine!

[@jaredburns6652]

Week 4 1999 ford ranger 3.0. And thanks for letting me buy the piston nuggets off the 3.5 ecoboost

[@christopherweise438]

All that tubing makes it look like an HVAC system.

[@emilschw8924]

Ironic way of producing cold air or hot air for cabin comfort...

[@kd5byb]

Yeah, that leaf tree'd me off too. It leafed me no doubt that someone didn't give a fig about this engine. It probably was pineing away for someone to give it the pear minimum of proper care, if not become the apple of their owner's eye! I'd not yet watched to the end, perhaps the damage isn't so bad that you couldn't make it cherry again? (sorry, couldn't resist)

[@rdeiriar]

From the data that i've seen, engines up to S/N 30266191 have silitec cylinders like this one. Later engines have arc-spray iron coated cylinders so in theory they should resist scoring better.

[@rdeiriar]

The changeover date was March 2015. And thanks again Eric, all the best for the holidays!!

[@davidg3944]

Any word on how the iron coating holds up? With aluminum about three times the thermal expansion/contraction of iron and steel, the ~300F temp swing the bores see from winter cold startup to hard running could put some serious shear forces into the interface.

[@lawrenceralph7481]

​@@rdeiriar...naturally mine is a '14...

[@kafklatsch3198]

@lawrenceralph7481 it was 5 years and many millions of them produced with the silitec before the change... so it was proven.. these failures are not the norm...

[@QMan1234red]

Watching Chino Moreno tear down a motor is always tue best part of my day

[@markpinther9296]

Those chains around 38:00 would make a great clock with moving parts. Question: what is the cause of bore score on those engines? Is it timing thing?

[@jsh6952]

Bore score is caused by fueling issues. Either overfueling that washes off the oil film or running lean and too hot, causing the piston to expand and rub.

[@racerx00]

Great editing as always. Thanks for another great tear down.

[@williamneedham7747]

Love the water pump skit it really made me laugh Brett is a star 😂 the most exciting thing I found from this teardown was that Blue has a twin Brother 😁 and as you know everyone loves the Blues brothers 🤣🤣🤣 love your videos Eric keep up the great work all the best Matt N 🇬🇧

[@stevebollinger3463]

Also a little brother. He uses a blue-handled screwdriver to pop that tube off the top end of the engine.

[@matthewghali2987]

the emotional journey you took me on with that water pump cannot be forgiven!

[@froddy32623]

This channel is the ultimate 🫵 to automotive designers from the people who ACTUALLY WORK ON THEM.

[@63bbray]

Cylinder walls look the the walls of an old Chevy Vega!

[@paulwells4203]

Geez that Brett, he's a caution lol. Your videos are enjoyable. With the Mercedes twin turbo V-8 I kept thinking thats a lot of technology and complexity for around 400hp. Maybe its to meet emission regulations. Keep up the good work, I like your laid back attitude.