Cadillac HT4100 In Depth Problems and Reliability.

[S2500Dog]

Hey everyone,

Im a little bored tonight, so I wanted to know about the problems and reliability of the Cadillac HT4100 V8 made from 1982-1987. I know Cadillac made some nice cars during this decade but when it came to the Powertrain Dept, Cadillac always suffered extreme nightmares from their engines, transmissions, computers, and electronics. Share your thoughts on this engine and what Cadillac should have done to make this particular engine bulletproof and reliable for customers back in the day.

 

[Colt45ws]

I want to know who was smoking what when they put iron heads on a aluminum block.

 

[S2500Dog]

I don't know what the $!#% they were smoking back in the day, they should have just made the engine cast iron with cast iron heads. It would made things more reliable and dependable.

 

[mrsilv04]

Originally Posted By: Colt45ws
I want to know who was smoking what when they put iron heads on a aluminum block.


Could it have been the same people who thought of building a 350 diesel?

 

[Schmoe]

.....or the 4-6-8 engine?

 

[S2500Dog]

What up everybody ?

Nobody want to talk or discuss about the HT4100, V8-6-4, or Olds 350 Diesel? I hope all of you are not hating on the cadillac lol.

 

[Colt45ws]

Ive never put a hat on the Cadillac.

 

[S2500Dog]

The only Cadillac I would buy and drive on are the 1977-1979 models with the legendary 425 7.0L V8.

 

[PF52]

Originally Posted By: S2500Dog
What up everybody ?

Nobody want to talk or discuss about the HT4100, V8-6-4, or Olds 350 Diesel? I hope all of you are not hating on the cadillac lol.


I think no one is interested in beating a VERY old horse.

 

[Trav]

HT4100 the equivalent of a Vega engine in V8 form.Junk from the get go.After 1 yr of misery and failure they should have quit and thrown an 350ci iron engine in the RWD car and a 3800 V6 for the FWD cars,it would have been way better.

Now i think of it a Gen II or III 3800 drive train or late model N* would be a great swap for an Eldo or Seville from that era.

 

[S2500Dog]

Ok guys, How about your opinions and suggestions on the legendary Cadillac 325 7.0L V8 from 1977-1979 models?

 

[Trav]

Most old iron caddy engines were good but why do you ask about these old engines? The 425,429,472,500 ci motors were all good.

 

[Oldswagon]

The biggest problem I remember about the HT4100's were the head bolts pulling out of the soft aluminum block. These engines were unrealiable and underpowered. GM was too focused on saving weight and built a poor engine. The '86-'90 RWD Cadillacs actually swtiched to an Olds 307 V8 from the 4100. This engine was then superceded by the TBI 305 Chev and an optional TBI 350 Chev.

The 425s were reliable but burned lots of gas and weren't overly powerful (like most engines from this era). 425's only made between 180-190hp (FI made slighlty more power than the carb). They had lots of torque though, but in a heavy Caddy they were no tire burner.

 

[S2500Dog]

I asked about these engines because I heard mixed reviews on the 472/500/425 series and nightmares stories on the 368, V8-6-4, and Cadillac HT4100. However, the 4.5L and 4.9L went on to be durable motors lasting up to 500,000 miles with proper maintenance before a rebuilt was ever needed.

 

[Norm Olt]

They extended the warranty when the 1st problems started cropping up. The motor needed the anti-corrosion tabs (that were very common with GM engines in that era) added to the coolant as well.

Mom's '83 (I think?) shorter wheelbase Coupe deVille (the Tobaccolac) got 21+ around town and pushed 30 mpg on the freeway with the cruise control set at 80 mph. Never really was much of a "tire smoker", though.

This was one of GM's 1st cars with a "computer controlled" powertrain, although it was not too much of a computer: just a lot of electronic modules, which, BTW, worked pretty good! The idea was to increase gas mileage (which it did) without losing the plush Cadillac "RIDE". Frequent oil changes, transmission service, new coolant every couple of years. Fix anything that needed fixing. A couple good thousand mile road trips per year to keep things warmed up & working. No major mechanical problems with this car, although to be truthful it was being driven by a "little old lady" who happened to smoke a pack-a-day well into her '90's (MOM!) and only went to church sporadically...

Best part was these cars had the cooling & electrical systems, a/c, transmission, suspension, rear end, etc. of the much heavier and more powerful BIG, BIG BIG! V-8 engines. They were very hard to break with the 4.1 motor.

As far as the engine was concerned it was really a rolling test-bed for the transverse application (4.1, 4.5 & 4.9 varients) that were not replaced until the Northstar came along, much later.

My brother still has this car down in St. Pete where it is not so "vertically challenged" by any hills, or Ohio winters, salt on the roads (except sea salt), and so on... About 88K miles on her, original engine & transmission, a complete body & paint redo.

Chocolate metallic paint, deep dark chocolate leather interior and carpets are still perfect, new headliner, tires, shocks, bushings, etc. Car pretty much looks like it did when it came off the line. New SONY radio with CD (GASP!)!

Probably won't last for much more than another 25+ years!

Cheers!