V8-6-4 - Cadillac's Worst Engine Blunder?

[@drivingmyoldcar1974]

Back in 1997, I drove a 1980 hearse built on a Cadillac v864 chassis from Maryland to California. It was also equipped with a 40-gallon gas tank. The 8-6-4 worked flawlessly. At highway speeds with the AC running, it got ~26 mpg.

[@jwelchon2416]

GM and Chrysler are using cylinder deactivation today and it's just as disastrous. It actually caused premature engine wear because of the uneven heat.

[@matthewlibanio8227]

My 2008 Avalanche has 520,000kms and is working just fine. Maintenance is key. Change oil regularly and it's totally amazing and reliable. Get cheap on maintenance and well you are going to literally pay for it.

[@keithbaker1951]

Don't forget about Hondas cylinder deactivation.. Honda accords burning oil out the tailpipe at 20k miles 😂

[@jared5021]

This is true on the Chrysler Hemi and the GM LS V8 engines. I had a 2012 Sierra that failed just out of warrantee. Truck was 5n years old and had 84K on the clock. Supposedly the technology works better on over head cam engines.

[@MamesJatthew29]

It’s actually true with ALL manufacturer engines with an MDS system. Prematurely wears the cam lobes. It’s just more common on GM/Chrysler OHV’s, than with the OHC setups of others. It all boils down to how you drive and maintain your rig. The way to beat it, at least for the long term, is (here comes the obvious)being religiously on time (and even beforehand, if driven harder/towing/etc) with your oil changes and using high quality full synthetic oil w/ equally high quality oil filters. Can even go a step further and have a shop perform a cam replacement with an MDS delete, if you’re already experiencing problems. I had bought my 2016 Ram 1500 4x4 with the 5.7 new and have had zero issues so far, with 112k on it, thanks to going above and beyond the maintenance schedule, in respect to fluid changes and basic maintenance.

[@jamesbosworth4191]

@@keithbaker1951 I see many Japanese and even Japanoid small cars blowing blue smoke, despite being late-model cars.

[@davidbroughall3782]

I was a teenager in a Chev Olds Cadillac showroom when the salesman was talking about this to my father. Very glad he ended up buying a Chevette. He drove it into the ground, but it lasted more than 10 years.

[@NorthernChev]

Can you imagine being the salesman, talking to an interested customer about a potential Cadillac sale, and end up walking out with a Chevette sale? Ohhhhh, that poor salesman.

[@davidbroughall3782]

To be fair, I don't think my father was seriously considering the Caddy. He was quite frugal. But the salesman put his whole heart into selling the caddy so my dad decided to be polite and let him finish talking.@@NorthernChev

[@ozzierabbit587]

Your father apparently was among the few who were happy to own a Chevette!

[@jamesbosworth4191]

@@ozzierabbit587 The Chevette was a big sales success for Chevrolet. Exciting car? No. Nice car? No. Fast car? NO. Hot seller? YES.

[@MrDan708]

It wasn't the only time GM concocted a novel idea, then bungled the execution.

[@milfordcivic6755]

See: Vega, Citation, Cimarron, DexCool, 3.6 timing chain, Northstar engine.

[@kylemlm]

I remembered this well with my parents and grandparents, they called this the "cheerleading" motor. 4 6 8 ...who do we appreciate. My dad bought two 82 Mercedes SD & D models 3.0 diesel next year. Talk departure of vehicles, but Oldman complain about Caddy all the time and it was in the shop all of time. I remember driving west Texas and Mercedes lack no power but it never gave us any issues.

[@bobbbobb4663]

My father’s 1981 Eldorado diesel experience turned him into a Mercedes man from 1983 onward.

[@kylemlm]

@@bobbbobb4663My Oldman did the same....

[@bobhill3941]

I always love when you upload, it's always a nice suprise. I've loved your channel for years. Adam from rare classic cars does a great review on the V8-6-4 too.

[@Sevenfeet0]

My first Cadillac was a 1980 Coupe DeVille with the 368 V8 that my mother bought for me used while I was in college. But I remember reading about the V8-6-4 car in high school and saw it at the dealership (my mother drove a 1979 Seville at the time). I would counter that the V8-6-4 engine was just one of the engine issues of the era. The Olds Diesel engine debuted in 1978 and was a performance and reliability dog for a variety of reasons. Still, fixes were made and Cadillac even made it standard on the Seville in 1980. I remember reading in a car magazine in 1980 that the V8-6-4 cylinder deactivation scheme went from the drawing board to production in 11 months, which means it was impossible to do any kind of real testing. The customers were the testing and the results speak for themselves. The early years of the HT4100 were just as bad as the V8-6-4 if not worse. To fix the V8-6-4, you just had to disable the system in a few minutes at the dealer. The HT4100's problems often required replacing the entire engine. And finally, there's the Buick 4.1L V6 that was on offer at the time. Is there anything more of a "we're hedging our bets" engine than this one? Why have a large V6 engine with the same displacement and rated MPG as the new "High Tech" 4.1L V8 Cadillac was touting? Somebody knew this new engine might not end well.

[@recoveringnewyorker2243]

I was a junior mechanic at my local Cadillac dealership in 1981. I remember this well. I wrote about this very subject in book one of my 4 book exposé series “All in a DAZE work” (The decline, and fall of the American work ethic.)

[@BlackDogOfLyos]

Do you happen to remember what the name of the solenoids that controlled the 864 were called?

[@eddiestanley135]

At least this one just had slow electronics and a shudder in six cylinder mode. Easily disconnected and at least it did not commit suicide via lifter/cam obliteration.

[@troynov1965]

I worked at a GM dealership from early to mid 80s , One of my friends was a mechanic there as well and did the engine rebuilds. He said the only thing those and that god awful GM Diesel engines was good for was a boat anchor.

[@mikee2923]

Actually the engine blocks from the Oldsmobile diesel are quite desirable. It’s a heavy duty Olds 350 block.

[@bobbbobb4663]

@@mikee2923DX block. Pre DX is the boat anchor

[@jamesbosworth4191]

@@mikee2923 When used as a gasoline engine, yes, but as the diesel it was intended to be used as, only the final version was any good. The others were horrible.

[@bigcrowfly]

Today companies including Mazda, Honda, GM, Ford, Mopar, VW, all revised this technology, all with bad results. So much that there is an industry selling various mechanisms to turn it off.

[@johnwhitneykokalis9990]

I'm not so sure about that. The technology is flawless in my Cadillac ats 3.6 and my 2023 Canyon 2.7, 4 cylinder. And almost every engine in GMs engine line up.

[@gregorymalchuk272]

​@@johnwhitneykokalis9990How many cylinders can it turn off?

[@fleetwin1]

As bad as this design was, at least it could be deactivated, so the engine ran normally. That being said, I feel that some of the later engines were much bigger blunders indeed....

[@kencornwell]

I had one and it was disconnected and I loved that car very much. What a sweet ride. The built in CB Radio was very cool. Listen to the radio and when the CB came on the radio would cut out. Fun driving on the interstate. All around great car.

[@xpired5729]

How did you disconnect it ?

[@kencornwell]

@@xpired5729 Luckily it was already disconnected. I think they did that to all of them not long after they bought them. I am sure it is not hard though.

[@xpired5729]

@@kencornwell I’ll do some research thank you

[@komradkolonel]

I know a mechanic that worked at a Buick/Cadillac dealership during that time and he said they replaced those engines all the time. They would get crates of them in every week. He said the cylinder heads along with the pistons warped and cracked and sometimes the blocks did too. Then the Cadillac brass sent them a memo to deactivate the system that shut the pistons down. Without that the engine worked fairly well.

[@TeeroyHammermill]

V8-6-4 had a low failure rate. The HT4100 was the one with frequent failures.

[@whitsundaydreaming]

The worst was yet to come… HT.

[@rudiknaus4139]

@@whitsundaydreaming and followed by the early horrible NorthStar 🙈🏁

[@The_R-n-I_Guy]

If the government hadn't rushed American car makers to such drastic increase in fuel mileage. Cadillac could've perfected this engine and not tarnished their reputation. I understand why the government did this. But they really should've given American car manufacturers time to get things right. With their demands. They ruined American cars forever

[@jamesbosworth4191]

I think instead they should have forced the oil companies to go back to drilling HERE in THIS country, as they are doing now, with the threat of Nationalizing them if they refuse. That would have solved our Dependence On Foreign Oil problem.

[@ChrisWhalenCPA]

I was so happy to see one of your videos.

[@JCVACCARO]

Yes. This is a great engine once you disable it by disconnecting a few wires. I'd take it any day over the Hook and Tow 4100.

[@Coodeville]

I know a bunch of guys who did this. Theyre still going strong today

[@1_BlackDog_23]

All it is a simple pull of a fuse lol

[@marko7843]

No fuses, just a single-wire plug on the side of the transmission. I actually added a flat chrome toggle switch on each side of the radio: 1 held the antenna in whatever position it was in, and the other held the engine in eight cylinder mode. Useful for compression coming down Donner Pass...

[@t.l.robinson2162]

You do not have to disconnect wires to deactivate cylinder displacement. Just lock it into 8 cylinder mode through the mileage display on the dashboard.

[@TexasScout]

I can remember in the early 80s, I was in the Chevrolet dealership in Refugio Texas picking up some thing for my truck and there was a cowboy yelling at the service advisor, “God dammit if I want to buy a new Cadillac in Dallas and driving to Corpus Christi and 95 miles an hour I wanna be able to do it!” Is Andrew was toasted had to be towed in to the nearest GM dealership.

[@pcno2832]

It doesn't sound like much of a disaster, at least it didn't have to be. They got it working right after 1 year and even before that, customers could still get their cars running right by deactivating it. They probably should have kept the V-8-6-4, but deactivated the rough 6 cylinder mode, making it a V-8-4. The real disaster was the 4100, which was rushed into production and gave customers much more grief than the V-8-6-4. A V-8-4 in all of their RWD (and 2 ton FWD) models would have given them time to get the 4100 right for the '85 FWD C-bodies, which were light enough for an engine that small.

[@Paramount531]

I had occasion to ride in a new V8-6-4 Seville. My overall impression was that my 1974 Pinto provided a smoother and more satisfying driving experience, and wasn't as fugly as that bustleback Seville. Sure, they have these systems in modern cars, but they lead to premature oil consumption, broken pushrods and ultimate early failure of the engines. Some years later I bought a used 85 Sedan deVille with the Hook and Tow 4100, it was underpowered but it was overall a smooth running engine. Mine suffered an oil pump failure but I had it shut down so fast that no damage occurred, I repaired it with an updated pump for the 4.5 engine. It was a fun car for a while, then I sent it down the road before the big repair bills would come due.

[@trainnerd3029]

Always a great video! I remember these commercials as a kid… I was a sophomore

[@OLDS98]

Thank you for this video. Cadillac had a host of issues in the 1980's and this engine was one of them. There was the Cimarron, the great downsizing debacle of 1985 and 1986. It took them years to come back from all that madness. They are working their way back right now. The market changed a lot during this time too. I wonder how people would feel comparing this engine to the Northstar V8. The 4100 got upgraded to 4.5 and 4.9 liters and that was a good engine once they upgraded it. Thank you for posting this video.

[@mikee2923]

Cadillac basically stole the Northstar engine from Oldsmobile. It was nothing more than a larger displacement version of Oldsmobile’s Aurora V8 from the early 90s. Cadillac also pilfered FWD from Oldsmobile’s 1966 Toronado for the 1967 El Dorado. I still believe this is why Oldsmobile was able to produce their 455 in 1968 while Pontiac and Buick had to wait until 1970 for theirs.

[@jamesbosworth4191]

@@mikee2923 I thought the Aurora's V8 was a small-bore version of the Cad's Northstar engine.

[@johneldorado]

Cylinder deactivation is STILL a mess for GM. Go ask modern owners that didn't get this deactivated on their full size SUV's, it has wiped out their engine. All to save a few dollars a month of fuel. There's been a class action lawsuit over it. CAFE was one of the worst policy decisions ever for US automakers and for consumers.

[@joshuagibson2520]

Cafe and also cash for clunkers.

[@cjespers]

Like someone said, it might be bad, but the 4100 was really really bad. Thanks for the video.

[@michaelcoonce6694]

The engine was fine. The problem was the computer systems

[@Portuguese-linguica]

Cylinder deactivation has caused nothing but trouble.

[@michaelbaumgardner2530]

Always wondered what the deal was on the 864...Great Video As Always.

[@danam0228]

I always wondered if that engine was a constant headache and very short lived. Good to know that they did address the issue(s)

[@patrickmcgoldrick8234]

Yea, it was a better move,with replacing it with the HT 4100,a legendary power plant,that you could get 50,000 plus if you took care of it.

[@ohguy1991]

@@patrickmcgoldrick8234 I hope that was sarcasm

[@patrickmcgoldrick8234]

@@ohguy1991 It was.

[@jamesbosworth4191]

@@ohguy1991 It was.

[@bruschmidt9943]

I drove a gorgeous new Fleetwood Brougham at the dealership in 1980-81. The salesman proudly explained the efficiencies of the V8-6-4 engine. During the drive, it stayed in "8" about 90% of the time. For a few seconds in went to "4" & never saw the "6" happen?

[@patrickmcgoldrick8234]

The engine was great,the 6.0 should have given the 4.1 injection system it probably would've great drivability, decent fuel mileage would have been decent,and the big plus the engine would have lasted a long time unlike the aluminum cast iron liner HT4100.

[@Mr6384]

I’ve actually started to look around for one that still works!

[@rayrussell6258]

Not just V8-6-4 is in the running for worst, the NorthStar engine with poor head sealing is at least as bad as that earlier mistake. Ford looked into V8-6-4, a design that actually came from a third-party company, but rejected it before ever bringing it to pre-production. We saw the problems. So that third-party Company pitching it to Ford took it to GM, and the rest is history.

[@rustbeltrobclassic2512]

Cadillac never recovered from that engine, because the 4.1 was trash and while the 4.9 was reliable, it wasn't that powerful.. so the north* was released and that was worse..

[@robertdiehl9003]

Biggest mistake my father bought was a 1983 Cady 4-6-8 in 1987....

[@MrJayrock620]

If Cadillac had the time it could’ve been a flagship engine, but they had a firm deadline to meet the new CAFE standards within. Honestly I think they would’ve been better to go with the 350’s or 305’s they already had at hand from other divisions and upgraded them to fuel injection to give them a one up over the lower brands.

[@johneldorado]

They should have just paid the gas guzzler tax. Would have been cheaper and would have kept loyal customers. Who knows how many people when import and never looked back. The European makes like Mercedes just paid the gas guzzler tax rather than rube goldberg engines.

[@mikee2923]

Cadillac basically did begin using other division’s engines for a while. They couldn’t do it right away. It was still fresh in the public eye the lawsuits from the late 1970s when GM began the corporate engine experiment and got sued for using lesser division’s engines in premium division’s cars. While GM prevailed in the lawsuits they lost in the court of public opinion.

[@jamesbosworth4191]

@@mikee2923 I think they lost at least one of those lawsuit's, if my memory is correct. They had to start including a disclaimer that a GM car might have an engine made by a different division.

[@workingcountry1776]

Ironically 40 years later they still have reliability issues with displacement on demand. It simply doesn't work right even now

[@jamesbosworth4191]

Because it is forcing the engine to run in a way that is bad for it.

[@nucleargrizzly1776]

My friend's dad bought one brand new. It was fantastic for about two weeks. Never worked after that.

[@ozzierabbit587]

Have to wonder what GM was thinking when they introduced this.

[@howebrad4601]

Most of the problems domestic manufacturers had in the late 70s and early 80s were caused by rushing incomplete changes to market to meet fed fuel economy or pollution requirements

[@jamesbosworth4191]

I second you.

[@gregfielder4763]

GM made a lot of mistakes in the late’70’s and’80’s trying to meet CAFE standards. Just another example of government overreach.

[@dmandman9]

It’s an example of incompetence as well. Lincoln was able to accomplish it successfully without disastrous results. They simply used a 302 and fuel injection in their Town car.

[@mikee2923]

I agree. Government overreach is basically responsible for the slow motion collapse of the American automotive industry. They started losing market share in the early 70s when government basically regulated muscle cars out of existence. Corporate greed also played a part. The CAFE standards became so onerous that they forced domestic automakers to produce Japanese style cars they had no real experience making. Why would anyone buy American when Japan had perfected the small FWD car? Americans really want a big and safe V8 powered automobile which explains why pick up trucks are by far the best selling vehicles today. The final nail in the American automotive industry will be the current electric cars our government is trying to mandate. When this scheme fails, the car companies will go bankrupt from investing in technology that clearly the majority of Americans do not want. The infrastructure clearly isn’t there for this to happen. The domestic automakers already know they’ve been dubbed to big to fail and the government will bail them out with our tax dollars once again. That is until we can no longer afford to do so. With $31 trillion debt, that day is fast approaching.

[@phebelle04]

Volkswagen sold cars with fuel injection in 1968. The regulations forced Detroit to get off their asses and do some engineering. The fact that they weren’t very good at it is not the fault of regulators.

[@dmandman9]

@@phebelle04 it wasn’t just the electronics. They went cheap on things they’d previously excelled at. For instance, GM had a transmission with a good reputation; turbo 350. But they decided to put the weaker turbo 200 which was meant for compacts in full sized cars with predictably disastrous results. Meanwhile, the Japanese such as Toyota and Honda were on the upswing. Again EVERY car sold in the USA had to meet the same regulations. But we tried to do it on the cheap. If the v8-6-4 had been the only mishap, that wouldn’t have been so bad. But they promptly followed it with the disastrous HT4100. They should and could have done better.

[@mikee2923]

@@phebelle04 If you remember correctly GM had mechanical fuel injection in the mid and late 50s. Chevy and Pontiac both offered it but it was costly and not a very big seller. The American automobile manufacturers were doing quite well until the federal government stuck their nose into something they know absolutely nothing about. Mandating emissions and fuel mileage standards is not the business of the federal government. A lot of people seem to forget the government’s responsibility is to protect the freedoms granted to the citizens by the constitution. It is not their job to protect us from one another. We ignore this to our own peril.

[@leewatts5956]

I love this channel. Please someone tell me the name of the intro music. I really like it.

[@tirebiter1680]

The V8-6-4 had the unique ability to turn off 2 or 4 of its cylinders. It could also turn off 8 cylinders, when you wanted it to keep going. Cadillacs were famous for their high Quality, Then they made the V8-6-4 and that diesel.

[@neilhartigan7456]

I had a 1981 Cadillac Deville to disable the 864 you unplugged it from the back of your transmission.

[@Paulie1232]

American car companies have been first in a lot of technology 😳

[@steveosgood9182]

my dad had a 1981 Caddy with the V8-6-4. Awful engine. Here we are 40 years later, and the newer AFM, cylinder deactivation is still a problem. . Sure, you will see posts by owners who have no problems with theirs, but the % of owners with problems is off the charts. One mechanic commented that he made a good living just repairing the AFM engines, and I believe him.

[@markkramer487]

I was right in the middle of this debacle as auto repair shop owner and a livery cars owner. We shut down the the modules on V8 6 4 so the problems stopped and still got high miles out of it but it was a underpowered pig compared to 425 cu earlier. The 501 was another pig that had numerous fraulties. The HT 4100 WAS THE WORST we just waited for it to breakdown at about 120 thousand miles and replaced it with the Olds 350 witch gave us high mile results. Always had Lincolns too that's why the Lincolns took over the livery buisness!

[@jamesbosworth4191]

You got 120,000 miles out of an HT4100??? And what was wrong with the 500 cube engine, besides the high oil consumption?

[@tonychavez2083]

it was very novel at the time, only high rollers had these cars in our town.. back when cadillac was something still very special.

[@billybotts9521]

They should have kept that engine and ditched that HT4100. I loved my 1981 Coupeville.

[@coarsegrind]

My father had one of these. 864 was disabled but was still an absolute dog.

[@VTCharley13]

I know it was the malaise era, but 140 hp and 265 lb ft out of 368 cubic inches seems especially pathetic.

[@jamesbosworth4191]

@@VTCharley13 No other way at the time to get it to pass the 50,000 EPA smog certification. If you don't pass that, you can't sell your cars, unless you want to try to sell them as racing cars that are not street legal. Just think, a Cadillac racing car!

[@TeeroyHammermill]

@coarsegrind: Car and Driver tested an 81 Sedan Deville V864 and got 0-60 in 11.6. Not bad for 1981.

[@scottsteeves]

I remember working on these things, what a nightmare.

[@BruceLee-xn3nn]

Yeah my 90 year old grandpa had 12 of them at one time. People would sell them to him for practically nothing

[@TeeroyHammermill]

What was so nighmarish about it? It's just an old V8

[@jamesbosworth4191]

@@TeeroyHammermill Trying to get it to run smoothly.

[@kyleharris8150]

My first car was an olds delta with a caddy 500 under the hood, loved that boat.

[@the23rdbryan]

Great idea that was simply ahead of its time.

[@michaelpfaff6009]

We had a 1981 Fleetwood Brougham with the V8-6-4. We had a toggle switch put in that activated or deactivated the V8-6-4 mode. In town driving it was always in the V8 mode only. On the freeway the V8-6-4 was turned on. I think that it should have been a V8-4 only. The V6 mode had that slight vibration that was always present. Otherwise, it ran fine for 10 years.

[@warmstrong5612]

Ah, the old Cadillac V8-6-4-0.

[@spooderdoggy]

0, zero! 😆😂😂

[@t.l.robinson2162]

I will take this engine over the HT4100 any day.

[@stevek8]

I love your thumbnail. I had a 77 Cutlass. Have you done a video on it? I looked about a year ago and didn't find one.

[@zillsburyy1]

cadillac turning into a sports car is their biggest blunder

[@brandonpetchnick1182]

I love every episode you produce. What are your thoughts on the Pontiac formula 400

[@jl456]

Where’s the fuel filter at on these engines?

[@milfordcivic6755]

GM still has a severe issue with the cylinder deactivation on the 2021-2023 Silverado wiping out cam lobes.

[@johnwhitneykokalis9990]

I beg to differ. Had a 2019 with deactivation in a 5.3 with no issues and my best friend who ownes a GMC dealership says it was the 8 speed tyranny that has issues not the deactivation issue.

[@jonmcneil222]

I like the information. And the way you go into when and where it started. And you're a facts are on point. But that let you know that the tech they don't spend time to perfect it like they supposed to. Then we the people who buy these vehicles have the problems fixing the problem might not be out of pocket but the time you spent stressing back and forth to the dealership you will not get back 😔

[@johnwhitneykokalis9990]

Most people, especially foreign car lovers, bash GM for things like this, but at least GM was trying to innovate new ways to jump through government hoops so people could still drive a large luxury car. I blame the computer engineers who told GM that the technology was fool proof and lied, big time. But look where we are today thanks to GM for taking risks. I am sure japan mimicked our technology and consumer reports gave Japan the credit for it being around.

[@vintagehaynesflute]

They took the risk but we customers paid the price

[@jamesbosworth4191]

Those magazines are constantly telling people that the Japanese invented this or that, when in reality, hardly anything was invented by them. It is easy to improve on what already exists, but very hard to invent something that never existed before.

[@thomasconnolly7452]

My father had that in. SDV. We called it the 7-5-3 because it shook like it was running on odd cylinders. I don't recall how they fixed it but he replaced it with a new 84 CDV than ran great.

[@r.aidenbach5667]

Yes, it performed OK as long as you disconnected the 6 & 4..... then it was similar to the 1980. Too bad what came after was even more disastrous ! The HT4100 & HT4500 It's a miracle the Cadillac brand survived that nightmare !

[@quentinsheckles3548]

I've heard of the HEMI v8's multiple displacement system in 06, and active fuel management with gm's 5.3l v8, but not an engine like that before.

[@austinfrazier7325]

MDS is not good overall even today. I have a 2019 Honda Pilot with the 3.5 J35 V6. It’s called VCM. I disabled it with a $90 module. -On these engines the oil passages for this system in the heads is narrow and will get gummed up over time. -Honda uses expensive fluid filled motor mounts to cushion the vibration of the cylinders turning on/off. These mounts fail at a much quicker and higher rate with VCM enabled. -The VCM system is known to kill the 6spd auto transmission. Something about the computer logic and the constant locking of the converter. These issues took years to discover and document and cost people a lot of money. This video is wrong. Stay away from MDS systems or make sure you disable them.

[@ferdiejpacheco5613]

All it required was a 30 minute disconnect at the dealer. I did it immediately with my Moms 81 Seville.

[@jamesbosworth4191]

But many shops, both at dealers and regular garages, were afraid to do so, feeling that the EPA would consider it to be "tampering with the vehicles emissions control system" and fine them $50,000.00.

[@snappers_antique_firearms]

I didnt know they ever did this back then. I have a 2007 cadillac escalade that has a l92 6.2 v8. Mine was extremely early and has a very rare version of the l92. It has Cylinder deactivation Installed on the engine. It is not active but its there. For what i read it was planned that it would be used and at the last min it was dropped. So the very early l92s have Cylinder deactivation but its not Active in the computer. I used to own a performance shop and i have hptuners. i have been wanting it see if i turn it on in the computer if it will work.

[@dj33036]

As if this wasn't bad enough, they followed with the H.T. 4100. Cadillac is still recovering to this day.

[@B81Mack]

It didn't end there, GM insisted on using displacement on demand engines in half-ton pickup trucks very recently. Still a problematic hunk of junk design.

[@John-h6y8t]

The new engines with DOD or AFM cylinder on demand systems are still failures. Lifters fail and eat the cams. $7,000-$10,000 repair if it can be fixed. If not, then a new engine is required. I wouldnt just deactivate the systems used today. I would replace the lifters and heads right after i bought them. Might as well do a cam since you have to take heads off to replace the lifters. It voids the warranty, but the warranty issues will be gone and you'll be left with a great running V8.

[@arevee9429]

Was the V8-6-4 worse than the 4.1 liter? All that was needed if it failed was to disconnect it (cylinder deactivation) and then the engine returned to a normal, reliable V8 based on a proven engine family. The 4.1 wasn't particularly reliable and it was a dog. The V6 was certainly not "Cadillac smooth" or powerful. And the 350 diesel doesn't even warrant a comment.

[@TS1964]

My dad had V8,6,4 all I remember is it was slow! His next car was the Buick Park Avenue ... come to think of it, he never bought another Caddy after that.

[@Piggypongtheavgeek]

What about the HT4100 engine. I remember Camshafts, head gaskets. Just problems anytime one came in the shop

[@justsumguy2u]

It wasn't really so much programming as it was lack of computer technology at the time. Put simply, engine computers of the day were too slow to react to driver input. This is why many late 70's--early 80's turbo 4's and turbo Buick V6's blew up (no, not the Grand National engine, before that). When spark knock happened, the computers were too slow to retard the timing, allowing detonation and engine damage

[@mikee2923]

Did Buick ever address the fatal flaw with their 3.8/4.1 V6? They had an oiling system that pumped the oil to the top of the engine first and the crankshaft and connecting rods last. It was a reason for me to never own a Grand National. I remember they were top speed limited from the factory at something around 112 MPH. Thinking due to that issue? The V8 f bodies weren’t top speed limited. I was able to bury the 140 MPH speedometer in my 89 Formula 350 with ease. Not a big Chevy fan but at least they stayed together.

[@justsumguy2u]

@@mikee2923 The problem was that the oil galleries in the engine were undersized (a problem they inherited from Buick V8's)---if I'm not mistaken, they enlarged them in the mid-late 80's

[@mikee2923]

@@justsumguy2u Thanks for the info. I knew it was some kind of oiling issue. But I still wonder why they limited top speed in the Grand National turbo 6 but let the Chevy V8 unlimited. Had to be some kind of warranty worry. Maybe because the TPI didn’t rev high enough to stress the bottom end of the small block. The F bodies were only 2 bolt main blocks while the Vettes were 4 bolt blocks. The cast bottom end of the 2 bolt small blocks were hardly bulletproof.

[@TeeroyHammermill]

@@mikee2923 : The 3800 fixed all those problems circa 1987.

[@mikee2923]

@@TeeroyHammermill The 3800 was the FWD version of the Buick 3.8, correct? I seem to remember that the only RWD car it was put in was the 89 turbo Trans Am pace car. I remember it being something about a redesign of the Buick V6. If you know the details, please provide them.

[@rodneybrand8521]

That thing was a nightmare ..hated to work on them..luckily some couldn't be fixed ..just replaced..at least it could've been deactivated if done soon enough ..

[@vintagehaynesflute]

I bought a 1982 Cadillac Fleetwood with the V8-6-4 engine. After a trip a week to the dealer he finally turned the system off after a year. I swore off Cadillac until 1995 when I bought a Sedan de Ville with the Northstar engine. Three replacement engines later I dumped it and got a Mercedes E300 diesel and never looked back. If someone gave me a modern Cadillac I’d take it and sell it and put it towards another Mercedes. To me Cadillac ceased to exist after the 1976 model year!

[@DavidHall-ge6nn]

I had the even more disastrous diesel, and a friend got the HT4100 in '82, despite my cautionary tales of woe. Neither of us ever bought another Cadillac.

[@patrickmcgoldrick8234]

Many others followed your footsteps,and never bought another Cadillac,and anything from GM The sad part is American cars in the early eighties were just not that good,and some people bought a Toyota,or Datsun,or another Japanese male,and never looked back.

[@patrickmcgoldrick8234]

I ment to say make.

[@jamesbosworth4191]

@@patrickmcgoldrick8234 The ones that were not "Cutting Edge" and "Innovative" and "Years Ahead" were fine.

[@patrickmcgoldrick8234]

@@jamesbosworth4191 Or nobody sweats the details like GM, during the Roger Smith years.(During the early eighties).

[@pjcornell9691]

I recall as a boy many neighbors bought these 4,6 8s brand new. It would hunt too much between 4,6 and 8. In short order under warranty the dealers would convert the cars back to fulltime V8s... Now my C8 has a V8/4.

[@86twin]

Probably would have been better off with just fuel injection.

[@201950201950]

Northstar

[@alliejr]

Sadly, Cadillac’s botched implementation has poisoned that efficiency feature to this day. Many manufacturers now implement this technology from GM to Mazda to BMW to Honda but few advertise it because of its undeserved bad reputation.

[@geoffreyharris7822]

No the HT4100!

[@marko7843]

Actually, there were exactly a DOZEN ePROM updates - I drove #13 for over a decade. How ironic it is that the "modern" deactivation systems have great computers but mechanical problems buried deep in the engine... As long as they were still using OHV engines they shouldn't have messed with the lifters, they should have stuck with the Eaton solenoids perched on top of the rockers! I never had one bit of trouble with the solenoid system or the latest computer. However, the engineers overlooked 2 totally separate things that hurt mileage & performance, even while they were brilliant enough to create an ACTUAL On-Board Diagnostic system 15 years before OBD2, accessible through the friggin' climate control buttons - something I don't know of any other manufacturer ever doing... 1. While a back-pressure-controlled EGR valve was a clever improvement on regular engines of the day, it was a brainless idea on an engine that CUTS its exhaust flow at cruise! The floor jets below the throttle body would carbon up & require drilling out, but far worse (on a long-stroke engine hobbled by a 2.41:1 axle ratio) was the EGR going away at the same time you were loading 4 cylinders more heavily. Combine those two results and you could not run as much spark advance as you needed to... 2. These cars had the first cruise control integrated with the computer. Later on, Chrysler was smart enough to use this advantage to actually drop a gear in the transmission if necessary to hold the car back going down hills! Unfortunately, Cadillac did NOT use this advantage to hold fewer cylinders while the Cruise was controlling the throttle. The engine still gave the throttle response, and cylinder activation, that a human foot would want. Oh, to answer the question asked, the HT4100 was Cadillac's worst engine disaster... the 350 Diesel was Oldsmobile's.

[@aspecreviews]

I agree. Solenoids to force the valves open and keep them open are a MUCH batter design than collapsible lifters that will eventually make terrible noises and just collapse prematurely.

[@marko7843]

@@aspecreviews Thanks. And just to be clear, the valves are left closed for deactivation, the cylinders acting as air-springs. The original system rotates a novel rocker-arm nut to release the fulcrum and let the arm move up and down while the valve is held closed by its spring.

[@aspecreviews]

@@marko7843 very neat! Honda does a similar thing with VCM, and it causes the engine to burn oil. The vacuum in the cylinders causes oil to seep by the piston rings.

[@stacygrenier7932]

Favorite car

[@Thankyou_3]

😂 I personally think Honda made the worst cylinder activation engines. Especially, their Turbo engines are the worst for oil dilution issues.

[@walterbatman7949]

The HT 4100 worse yet

[@chrisreed26]

As someone that was alive and bought one new during this time I can tell you it was NOT called or pronounced V8-6-4 but it was called or said 4-6-8. No dealer said it how you said it! Just an FYI. I bought a new one back then! Mine was halfway decent. We traded every two years so it was not a problem.

[@TeeroyHammermill]

It was called V8-6-4 Fuel Injection. All the TV ads and literature said this.

[@doolallyproductions7234]

Man 500 cubic inches so much torque and power

[@westhavenor9513]

Mostly torque, power was pretty much smothered by then

[@jamesbosworth4191]

@@westhavenor9513 The first few years of the 500 had 400 horsepower!

[@Adam-nv9zo]

Cylinder deactivation is bad, mkay.

[@jaspal666]

Man, love the content. But, slide a few bucks for a chap to read the copy.

[@g2skinny]

I’m a mechanic and replace more 2005 and up ls engines with afm more than anything else probably 4 to 1 this was the first dumb idea gm had back then been a long time ago

[@scottymoondogjakubin4766]

Wouldn't closing the valves hamper the remaining active cylinders especially still not cutting the fuel off to variable cylinders ? Amazing it eeked out almost 20 mpg

[@T-bird_Johnny]

First video I've seen on this channel that i dislike and strongly disagree with. Ask any reputable engine builder, cylinder deactivation is terrible for an engine. All these years later and gm still cant get it right the aftermarket sells tons of cylinder deactivation delete kits. It was a terrible idea forced out by the authoritarian government overreach enacting ever more strict regulations to please the climate cultists.

[@joshuagibson2520]

I didn't notice that it was said anywhere in the video that it was a good idea. Nor did the host seem to voice support for it.

[@T-bird_Johnny]

​@@joshuagibson2520 @7:40 the host claims had Cadillac spent more time developing the system it could've been a success, the purpose of my original comment was to point out the incorrect nature of that statement since GM, Cadillac's parent company, is still attempting to use cylinder deactivation to this day and it does not work properly. I've heard of Silverados that will blow up on the drive home from the dealership due to malfunctioning cylinder deactivation systems.😅

[@jamesbosworth4191]

Not the climate cultists, the gas mileage freaks.

[@marko7843]

@@jamesbosworth4191 Same crowd...

[@jamesbosworth4191]

@@marko7843 Back then, there was no such thing as Global Warming. We still were expecting a 2nd Ice Age. Eventually.

[@Narrowgaugefilms]

It seems to be begging to have an overdrive transmission instead: spin it slower Vs. fewer cylinders at the same speed.

[@nunyabidniz2868]

GM is *still* experimenting on their customers w/ the cylinder deactivaton in the LS-2 on onward [I say "experimenting" because it is known to be faulty & grenade the engines in fairly low miles, well before the 500K the engines should be expected to last...]

[@adamf663]

Even if the engine worked perfectly, you can't get decent fuel economy when it is in a 5000+ lb. barge.

[@jimsharp5044]

FIL had a 81 V864. He got maybe a 1 MPG difference between V8 mode and V4 mode

[@TeeroyHammermill]

That's why they dropped it from most models for 1982. EPA rated 15mpg not good enough for CAFE.

[@pjimmbojimmbo1990]

the 4.1 was Cadillac's Biggest Engine Blunder, by a long lead

[@dillonvossen1144]

great content, as always - however, the exceedingly laboured cadence of the delivery was a no-go, you can do better!

[@rm742]

The 4100s wasn't any better u had to push it up hill and when u blew a head gasket the engine was gone.

[@johnball8758]

It would take you all day to explain all of GMs blunders.I haven't bought an American branded vehicle since 1984.I will never forget the service manager telling me they did not know how to fix my Oldsmobile.Never again!!