29th Oct 2002, 08:18

Seems the common thread of these engines is a hit or miss thing. I've known guys who, with excellent maintenance, never got more than 70,000 miles out of their engine, and some that went through several new engines before that time. There have also been stories of people getting 200k+ miles out of these cars without so much as a new spark plug. I guess the HT4100 truly exemplifies the old Latin phrase "Caveat Emptor" -- Buyer Beware!

30th Oct 2002, 01:59

I can't give up my 82 Sedan DeVille! Yes it is big and people are surprised at how well I can maneuver that barge. I just replaced the high-pressure hose on the power steering unit. Now I am trying to find the dang cable that plugs into the circuit board and plugs into the CB unit. Of course it is not on any schematics because it was the AM/FM, Cassette, CB model. But I cannot sell her no matter what my wife says. Everytime it breaks something the usual conversation is "We need to sell that damn thing." As you said before I would rather put money into repairing it than a car payment. Next major expense is the paint job. Motor leaks at the main seal, but I just need to find a mechanic to replace that for me.

12th Aug 2003, 06:34

I have the ht4100 in my 82 coupe deville, and that thing is smoking like a mother. But I love the car, and I plan on rebuilding the engine. You just can't beat the way, the caddy floats down the highway. And theres plenty of room in the back seat, for you and the ladies,!!! HA HA.

16th Aug 2003, 10:29

For all you owners of RWD Cadillacs afflicted with an ailing 4100HT have you looked into swapping in an Olds 403 or other GM V-8? It should bolt up to your transmission as would a Buick or Pontiac as they all shared the same bellhousing pattern. You might even get lucky and have a 200-4R overdrive or TH350 with the dual pattern bellhousing that would allow a Chevy engine swap without changing transmissions.

Personally, I'm swapping a Cadillac 4.9 into a Lumina. :o)

28th Sep 2003, 17:54

I'm a proud owner of 1983 coupe with the ht 4100. I've never had any drastic problems with my Lac. Just keep it up to speed, change the oil,anti freeze spark plugs all filters, and check your vacume hoses that's important in this 4100, because if one hose is cracked or broke you'll lack power. Ways to boost it>a high octane boost+top shelf wires and plugs will enhance your acceleration. I bought mine with 74,000 miles for 1,600 dollars. I added a Rolls Royce grille which I found at the junk yard and paid only $25.00 for it! I put 15 inch gold and chrome 100 spoke rims with the 2 inch fat white wall>$800.00. I also spend a lot of time looking for parts in the junk yard, like chrome add ons. Now people stop me on the road once a week asking if me I want to sell my ride. I was offered 5,000 for it yesterday, but I can't part with my baby.

23rd Jul 2004, 12:16

I don't know about anyone else, but I had a 1987 Brougham, 60,000 miles on it with the Olds 307 in it and I will never again buy one with this engine. It was extremely underpowered and unreliable. But the car was red and in mint condition and regret selling it.

12th Sep 2004, 08:49

My son just bought an '82 Deville. I wish I had checked this site before now that it seems the 4100 engine is so trouble prone. His was replaced a few years ago. It runs quietly and smoothly, it seems like it has more than 125 h.p., but there is a ping or knock at times. We really need to get an owner's manual as I we don't even know the fuel requirements for this car. It's not registered yet so we have some time to do some research.

3rd Oct 2004, 17:10

Well I got a 1985 caddi fleetwood-brougham and it is powered by the ht 4100. she had original 57,000 miles when I got her, but she just doesn't have the get up and go I need. I am a young guy with a very heavy foot. when I first got her I could get in and power lock her and make it set the tires a fire, but now she runs sluggish and smokes when she is ran hard while idling at the lights or stop sign... is there any other engine that will go in wit out changing a lot of stuff?

16th Dec 2004, 10:08

I have an 87 Fleetwood D'Elegance with 225,000 miles on it. The tranny only has 19,000. However unfortunately it does have the HT4100 which was rebuilt somewhere in the 150,000's, but now it sucks down coolant and the oil smells like coolant and the area where the block meets the head is soaked. The car is horribly underpowered and the engine has rod knock when it heats up. The HT4100 was horrible, you can change the oil and the coolant all you want you'll just be wasting your time.

21st Feb 2005, 11:02

I have an 1985 fleetwood just wondering what engines are compatible with the 4100 please give any info you can.

25th Mar 2005, 21:35

After reading all of your comments, I'm kinda on the middle of the fence here. You see, I've been offered a 1982 Cadillac Coupe De Ville. Would you all advise to go for it, or just walk away now. If it makes any difference in your opinions, I live in Canada eh! So if you think our weather might effect the engine, please do say.

20th Nov 2006, 12:55

I own a 1982 Coupe Deville with the HT-4100. I've put 6k miles on it since I bought it three years ago (sat for 2.5 years), and it now has 110k miles. There is a slight knocking sound in the engine that can be heard more easily from under the car. I've been told it can be various different things. I was advised by a Mobil gas station service center not to purchase the car based on this knock. I bought it anyway (for $1,700) and it has been running great. All I read online is horrible stuff about this engine, and it scares me, but I drive it very easily, with a light foot, using the weight of the car to guide me along more than the gas pedal... and it's been an awesome car for me. Yeah, it's underpowered, but it rides so smooth and gives me all the leg and head room a 6'3" guy needs. I plan to find a late eighties Deville or Brougham once I get the money, any suggestions/comments about the 5.0 or 5.7 engines in these models?

5th Nov 2008, 16:19

I own a 1982 Coupe Deville. I bought the car from a guy that spent over $12,000 restoring it. Needless to say, I paid much much less. I have been concerned about the motor based on what I have read. The car runs and drives perfect so far. It does lack the power of many newer cars, but that is kind of what I like about it. When I drive it, I just kind of fall back into the era of when the car was new. Is it possible if you drive the car easy it will last, or are the 4100's destined to fail?