The Mystery Of A 6-year-old Engine: What Caused This??

[@rustyengineer5060]

Just a guess on what might have happened to this engine. It may have had a core shift during casting. Machining the bore .020” oversize further reduced the wall thickness. Through time and heat a crack started to develop. When the coolant leakage was small it flashed off during combustion cycle (may have caused a misfire) but still ran okay. Eventually the crack grew large enough that when the hot engine was shut down, the still pressurized coolant system would start to flood the cylinder. Now every restart of the engine had varying degrees of hydrolock hammering the piston. It started to crack and then failed completely. The engine probably overheated because the owner was unaware of the coolant loss. It would be interesting to look at the valve seats in the failed cylinder and see if hydrolock caused any mushrooming. There may not be enough wall thickness to support a liner sleeve. You’ll find out when it’s bored out! Absolutely love your channel and the every day common sense you apply to your work. Keep it up!

[@CrawlingArizona]

Assembled pistons & rods.. Dex, I'd be interested in your idea to sell sets of used rods with new pistons already installed. with option to core exchange old rods. Love your channel! Keep up the great work. More videos of having fun off-road with you guys please.

[@bryanstrietelmeier2573]

Definitely

[@frankshelton5330]

I too was recently considering just a hone and pistons on a spare motor I have. I would do the swap as a service as well. Great idea.

[@timothyproksch2915]

Your fine your such a good story teller I’d set hear and listen to you explain shoveling cow crap . Your what’s called a natural. There’s slot of other people talking about the same thing but so far your the best

[@dirtbiketimemachine7167]

What he said 👆

[@jimmyjckjones]

I find most all of your videos interesting. Probably not the only one. ;)

[@papatomsthoughts]

Keep doing what you do. Each engine has its own challenges, so don't worry about doing same kind of engines. 😊😊😊😊😊

[@jeremyhanna3852]

I been Turing wrenches 20 yrs I bet it was run hot bad fan thermostat etc it cracked the block it sat around a while it leaked the coolant into cyclinder 2 threw crack they tried to start it and other cyclinders fired and exploded the piston in 2 end of motor

[@johnmiller2381]

Awesome channel. I second the fact that you’re a great story teller. Not saying you’re spinning yarns but you can verbally walk us through what you’re thinking. On a side note, your brother definitely adds to the videos. Thanks for the content and all you do.

[@dexjs]

Thanks for the tips!

[@ChevyHemi]

T4U Trick 4 You - welding cast experiment, The hole in the block lets say, if you weld the piece around the edge where you would stitch it naturally and weld around the edge where you would stitch it on the block then place the piece into place then stitch them together - so each has weld on them around the perimeter and you don't rush keeping it cold as possible then spot weld slowly into place like 22 gauge sheet metal, Hope that makes sense trying to keep it cold / tack welding slow / then final should be no stretch and hopefully no cracks, It did work for me and i hope you can use it but i still hate cast welding lol cheers love the info and comedy, good luck

[@shaneherman8906]

Keep em coming no matter what.

[@tsmith578]

Cast pistons often attend to do better because of cast forming gives them, Heat Treatment, that makes them a bit softer and more flexible , Hypereutectic ones are a higher silicone alloy, but they are more brittle, I guess you could say that they are a cross between forged and cast. It is often the same thing when it comes to piston rings, Moly rings are tough, but cast ones are still often a better choice in many engine combinations.

[@Thenorthforknwelder]

I got a wj and I think it needs a lifter.. or maybe a motor.. 392 swap?

[@v12alpine]

I think it ingested something laying in the manifold. Nut, bolt, chunk of the old motor, ect...

[@jesseduke694]

Maybey the cylinder cracked first allowing coolant to enter the cylinder hydrolocking the cylinder breaking the piston? Just a thought?

[@raynehardin9593]

Love your videos man I love Jeeps and learning more about them, I have a 96 5.2 zj, be cool to see some videos on a v8 🤘🏻🤘🏻🤘🏻🤘🏻

[@nickmcminn2137]

Hypereutectic has a higher silicon content which makes them lighter and less expanding than average cast aluminum or forged

[@cullengarrick9036]

The revised pistons are probably a similar weight to match what the crank is balanced to

[@98xj64]

Nickel rods are used to weld cast, last i bought was close to $400 a can or preheat and then weld, then reheat slightly every few minutes to control temperature drop. Wrap after multiple times with heat blanket. If done correctly, it will work

[@drewmurray2583]

Fram extra guard.... Orange Can Of Death 😅

[@TheVillainsProjects]

Would love to see you guys work on a Northstar V8 I know they're pretty notoriously bad haha

[@dalebailey1844]

Did the block crack and it hydro locked. I think I had one do that on my 2001 Cherokee. because I had antifreeze come out of the NUMBER 2 spark plug. But I just got another engine and never tore it apart. Just MAYBE.

[@jeremyhanna3852]

Super interesting video I bet when they pressed that piston pin in they cracked iy because they used a v block to hold it didn't get it on there right as opposed to that rounded holder just for 4.0 pistons like you have

[@brettthompson332]

All I can say is that I just had a motor in my own J+ep do this to And look the same as this! And one of my guess is that the oil was clean because it was just change !! after Not changing it for a really long long time . The motor run strong in tell i change the oil and drove home and the next day went to drive it and it started tic tick tic really loud ! so I started looking the Motor over did not find anything so I stopped looking and started the Hard drive test intel! just like what you got there !! But just like you I also keep old Jeep parts around .

[@jackjarmstrong14]

Dex, been watching you forever now… I’ve been having some issues with my 99 Cherokee 4.0 for 3 years now. But I’m in Colorado. Any chance I could DM you or message you to pick your brain? My rig is so modified that I’m having trouble finding a shop that will work on it. And I’m out of ideas now. Thanks! Love your content and always will!

[@carlt6932]

What is the problem with it. I've been a general mechanic for over 40 years. Maybe I can help.

[@CrawlingArizona]

My idea of cause, Think you're on to something with hydrolock. What do you think of this scenario?... Cylinders slightly over bored, thin cylinder wall between cylinders, crack in water passage / cylinder let coolant in then hydrolock from antifreeze. Was there any witness marks for damage on the cylinder head?

[@Pigtrapper]

They barely showed the head at the end. #2 definetly had something hit the head on, and around the valves. Could've been piston pieces. It was hard to tell

[@CrawlingArizona]

I need to go back and look for that part showing under the head, must have missed it.

[@ramyramirez8054]

the only thing i could think of is maybe ring land failure and it was driven hard enough when it happened for it to break apart, would be my best guess at the very least

[@manfredolson6889]

“Are you seriousin me?” 😂😂

[@Dmowery5036]

Wowzers! I think this is the best looking used engine I’ve seen.... until you took it apart. Lol.

[@jonlyons3376]

I like all your videos

[@jordenyoung-dixon9230]

Going to be rebuilding a 94 XJ engine, anything I should look out for?

[@A2ZREY]

maybe make a video of welding the block?

[@j.r.7907]

Maybe something got into the intake manifold when it was apart before and just sat there till they got at just the right temperature and angle or hit a pot hole and finally made it past the valve. Was there scaring on the backside of the valve?

[@dexjs]

That’s honestly what I’m thinking myself!

[@Mr383chevyboy]

Got any good places to order full 4.0 rebuild kits for a 2004 with power seal pistons

[@Wesley-uo3rn]

That FRAM filter unlife it. wix filter, Valvoline oil. 335k 96xj I've put 150k on the clock

[@halfcenturytruck]

What kind o' flashlights are you guys using here?

[@rudybishop9089]

and as far as the broken piston - wrist pin was ‘pounded’ in or over heated when installed.

[@craiglowy6745]

Hi dex are all 4.0 the same do you have a vid saying what is Difference between motors of the years I have an 06 motor and a 97 motor what’s the difference between years can I use the 97 into 06

[@dexjs]

Not yet!!

[@MN_XJ_Mike]

Probably just that fram oil filter that killed it

[@jamesherald5050]

If you’re going to weld cast you need to use nickel rods to do the job. But you need to clean it good to weld cast metal

[@98xj64]

Low oil flow wore piston casting apart unless spark plug touched

[@98xj64]

That fram oil filter is probably what went wrong 😅, needed a wix. Fram is junk from what I've seen and heard from other well known mechanics

[@98xj64]

Figured fram may been culprit, they are junk supposedly

[@frederickshipp8013]

​@@98xj64But the bearings were still OK, so that rules that out don't it. FRAM is junk, I'm one of those people who like to cut filters open and I cut open one of their top of the line filters the filter element had an area that wasn't even glued. I used to use Fram back in the 70s when they were made in the USA but I stopped using them decades ago.

[@98xj64]

@@frederickshipp8013 depends may have had most oil pressure but not sufficient enough or something partially blocking oil ports. I made that comment before he cut the one down that was on the engine 🤷, almost when the video first started, bad service in my hollow though. My next guess was sparkplug made contact but they didn't figure it was the culprit either

[@98xj64]

@@frederickshipp8013 maybe faulty machined piston that disintegrated, or connecting rod, caused it to wear one side premature until it dissolved

[@jeepguy04]

I have a 98 tj reman engine # 2 piston broke never ran hot or over rev y do I think it broke I had the Jeep for 2 yrs 12000 miles when it broke

[@76v8jeep]

Maybe that crack let water in cylinder and it hydro locked

[@brandondalton6396]

I would say it was just a faulty piston casting from the get go new parts these days suck

[@98xj64]

3100 and 3800 are bad for lower intake gaskets also, the GM motors

[@Pigtrapper]

Check the injectors. See if #2 is stuck open

[@TrailswithChad]

🤟🏼

[@dustyosborn3560]

Engine was running hot when cracked and water caused piston to explode

[@jacobwolfe9534]

I have a 96 Cherokee 4.0 it’s idling rough and dying and backfilling through the intake when I try to drive I already replace the crank sensor anybody know what’s going on with it?

[@nathanmccumber8965]

Clean out your throttle body. Idle positioning sensor

[@schmeatclips]

thats good antifreeze LOL

[@rudybishop9089]

Dex . . . . every now and then - listen to your F’ing brother !

[@rnagel2495]

First problem is that Fram oil fil🙄

[@vwclub3]

I'm at 14 min hydro lock is.my guess

[@christopherhilliard3681]

That oil looks thin I wonder if they left the break-in oil in it

[@christopherhilliard3681]

I wonder if that's the engine that the had the head off they may have dropped the chunk of aluminum in the engine if the mystery chunk will fit through either valves it would stand a chance of debris would do a number on any moving parts . It may have hung the valve open and when it dislodged it would smash a hole in the piston. A small nut will cost you an engine

[@brianandglendaharkin9457]

XJ TJ Rule 👍🏻🇦🇺🇺🇸🇨🇦

[@noberet]

Aliens. Extraterrestrials from Hardin County, TN.

[@BenHarrell69]

Or McNairy

[@noberet]

@@BenHarrell69 That would be domestic, not alien.

[@user-vk1ko9zw5y]

Moresa pistons

[@nitrous07me]

Don’t think it’s a jasper engine

[@KgiMedia601]

Moresa is made in mexico

[@ryanhubble9157]

First lol

[@JBdontcare]

A female

[@dexjs]

I laughed 😆