The HT4100 engine - bad in all years?

[J.C.]

Hi, Guys,
I'm thinking I want to by an '85 Fleetwood Brougham Coupe but I've heard the HT4100 engines are a disaster and nothing but trouble.  Were those engines bad in all years, or did Cadillac have it straightened around by '85?  All responses appreciated!!
John

[D.Smith]

Hi, Guys,
I've heard the HT4100 engines are a disaster and nothing but trouble.  Were those engines bad in all years?

Yes. 

Beautiful cars!   But the HT4100 will let you down. 

Unless you are going to transplant a 5.0 or 5.7 liter engine in one, don't pay more for an HT4100 equipped car than you are willing to walk away from.

[35-709]

Unless you are going to transplant a 5.0 or 5.7 liter engine in one, don't pay more for an HT4100 equipped car than you are willing to walk away from.

And that's the bottom line.

[G Pennington]

Didn't they come out with a 4.5 liter version in 1988?  Was it any better (durability-wise) than the 1982-87 HT4100?

[V63]

He’s probably wanting a RWD full size fleetwood brougham coupe...1985 was the last year of the aluminum 4.1 in those. The transverse FWD version aluminum motors had different block casting and were not interchangeable. The transverse FWD 4.5 version was indeed a better motor, just can’t swap it with a RWD 4.1.

[Eric DeVirgilis CLC# 8621]

The trouble with the 4100 engine is that there's every possibility the engine will be damaged beyond repair should major disassembly be needed. You can soak bolts until the cows come home but they will not budge - that is, until something cracks apart - instantly transforming the engine into a boat anchor and replacement is your only option. Replacement once cost me over $3,000 in a 1983 Fleetwood Brougham back in 2006; same job could well run over $5,000 today. OR you can walk away from all that and just stick with model years with known reliable engines in the first place.

Secondly, HT4100's performance is simply dreadful - especially in the full size RWD models. These cars struggle to keep up with traffic on even modest grades and acceleration is barely adequate, if you can call it that. 4 speed metric transmission in the 4100 years is no better either.

As beautiful as the full size 82-85 RWD Cadillacs were otherwise, their good qualities are overwhelmed by the bad. 

[Barry M Wheeler #2189]

I have heard that there was an "improved" engine in 1985 after so and so serial #s. I have them for Eldorado/Sevilles but not for the full-sized cars, or even if they did so for them. This is not to say that they were improved like the 4.5 was improved, but if you are really wild about the Fleetwood coupe, someone might chime in on this "possibility."

[Eric DeVirgilis CLC# 8621]

HT4100 was marginally improved over the years but main bearings were always weak in these cars. Even main bearings in 4.5/4.9 became noisy over time but they'd still run and replacement was not difficult (nor super expensive) in FWD cars. Not so in RWD models.

Even something as simple & straightforward like a water pump is a major headache on an HT4100 at this age.

[Scot Minesinger]

The 4100 was just terrible every year.  Do not buy a 4.1 powered Cadillac.

[Cape Cod Fleetwood]

My '87 FWD 'Commonwealth Edition' SDV was one of the prettiest cars I ever owned. Red, black 1/4 cloth top, opera lights, Rolls Royce grill, pin striped, digital dash, leather interior, wire wheels, it was gorgeous. And previously owned by a local radio personality. Loved that car! Then the anti freeze flooded the engine...

Somehow, by the Grace of God, Ritchie Olsen got Cadillac to pay for the repair after it was towed to his dealership from New Hampshire.

I'll keep that car a wonderful memory, and not another purchase. YMMV.

\m/
Laurie