Cadillac HT4100 Engine Assembly - Service Roundtable Laserdisc 

Yeah and for the opening act they gave the world the Vega 4 in the 70s. Lol

LOL you have no idea what you're talking about, just sensationalist gibberish.

I am sure glad you have a sense of humor!

It was a pos,headgasket and camshaft failures

You are insane

What??! This is a HAND-BUILT MASTERPIECE! 🤯

@@allentoyokawa9068 The camshafts in them were too soft.My dad has replaced one because of headgasket problems

You’re the only one with the original 4100 trust me 😂

​@@LowEnd31st no one gonna trust you. My 83 Brougham still running strong 41 years later. Now what

Main bearing are absolutely not supposed to be a "Wear Item" - if they need replacing that often someone has seriously fked up.

I’ve known of more than a few 200-300k + 4.9’s I’ve never seen that many on a 4.1, but my 85 Brougham has ~130k and to my surprise has given me very little trouble. We’ll see if that last…

I have a 30k mile 83 fleetwood brougham de elegance with 4.1 and runs perfectly in 2024

Left out headgasket and camshaft failures

Oh, yes, you forgot the porous block castings which let coolant "bleed" right through the block lol...... don't forget your coolant pellets when changing the coolant to keep them nicely blocked (and clog the water passages it DID need in the process)

@@joe6096 yeah, we called them Cadillac aspirins

I cut my teeth in the mid 90s after most of the bugs had been worked out of this design and Cadillac started all over again with a new one. Doing main bearing service or even an intake on the 4.5/4.9 engines was a treat compared to all the headaches that came in on the Northstar Sevilles/Eldorados. Ugh I'm glad those days are over

Same here started at a Pontiac Cadillac dealership. Cut teeth, hands, fingers, arms and assorted other body parts!😁 Parts department had a half dozen or so long blocks in stock! Now that is quality 😅

A good quality RTV such as grey greay or ultra black.. has excellent sealing properties.. better than gaskets... A lot of modern engines.. have their timing chain covers oil pans. Sealed Solely with RTV.. when applied properly. It seals much better than rubber or cork gaskets

@@johnfloyd2551Yup

It was one of the worst engines ever made. It was rushed into production in 1982 when Cadillac’s 6.0 liter V8-6-4 cylinder deactivation system ended up being a catastrophic failure in 1981. The HT4100 wasn’t meant to debut until 1985 in the much smaller downsized line of cars. But it was hastily placed into large, heavy full-size Cadillacs to meet government mpg CAFE standards. The various metals used in the engine were not compatible and caused the head gaskets to leaks and fail, head bolts would tear out of the soft aluminum threads in the engine blocks, oil pump failures and the engine was just too small and underpowered for the large cars they were being placed in.

@@jayson657 y does this not surprise me lol good ol gm it's like VW but american

Your right ex Cadillac mechanic here also

The Olds 350 diesel can be made reliable fairly easy and is simple to work on. Headstuds and a water separator and suddenly you have a 30MPG cool highway cruiser or daily

@@V8Power5300 This might be correct, but as a stock design it was terrible.

Adam brought me here.

Followed by a Chevy V8 in 91

There’s a good chance it’s been replaced or rebuilt already, even though the 87 version is allegedly “fixed” (it wasn’t). Problem is it’s getting hard to find replacements.

A lot of it carries over directly. Really the only major differences are the timing cover and thermostat housing adapter. The 4.9 seems to use proper gaskets in place of RTV slathered over everything, as well.

i mean they still cant get it right with the ls. they have problems with camshafts aswell. I've sceen one taken out of a 2012 or 14 i cant remember which and the lifter and 3 lobes were just completely fuckered

no

You're thinking of the '81 Cadillac. Clip a single wire and it goes back to being a dead-reliable cast iron 368 like the '80 version. It was the '82-85 HT4100 that was the disaster.

No this hunk of junk was hastily rush into production to replace the failed V8-6-4.

It’s just a shame Cadillac took until 1990-92 to finally put fuel injected small block Chevys in their full-sized cars. If they would have just done that in ‘82- while the other GM V8’s were still carbureted they probably wouldn’t have tarnished their reputation very much. Lincoln got away with it with the Ford 302.

@@jayson657They did in the 1993-1996’s as well on the Fleetwoods. I had a 1993 Cadillac Fleetwood with a TBI 350 Chevy engine. The same engine you would find in a pickup. GM should have used common engines across all their brands like Ford did. The 4100 was a result of bean counters rushing engineers into coming up with this engine. Maybe if GM shared engines, they could have saved money that way and concentrated on building a reliable engine. They should have just but a Chevy 305 with the 350 as an option in all their full size cars. I had an 80’s Caprice several years ago and while gutless, it was reliable as can be.

Unlike the diesel debacle (which was bean counter related), the HT4100 was an expensive engine to design and produce. Tighter tolerances, new design methods, exclusive assembly line, lots of aluminum. It was engineering that dropped the ball on this one. But Cad was in a real jam at the time. The Chevy stuff is out (not-compatible with Eldo/Seville FWD). And the big B/C cars were going to be dead after MY85. They also couldn't go back to a carb, being the poster child for advanced tech and focusing on it as a market differentiator. They had just released the industry first DEFI system in '80, with onboard diagnostics, digital climate control, trip computer, and other goodies you couldn't get from Buick, Olds or the imports. Best of all, the system was both reliable and well received. The whole impetus of the decision to pull forward the 4100 was that NHTSA could not come to terms with an MPG figure on the '81 V864 system that Cad was banking on to get them to '85. That's why it only continued on in the commercial chassis which was exempt. Cad did offer the Buick 4.1 V6 (carbed) in parallel with the HT4100, but there were few takers.

La Quinta California.