Your advice on the HT 4100 needed/appreciated
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HT4100 4.1, 4.5, 4.9 Discussion, Your advice on the HT 4100 needed/appreciated in Cadillac Engine Technical Discussion; I found a clean mid-80's Cadillac I am considering for a "fun" purchase. The car would be used primarily for ...
  1. #1
    caddymark is offline Cadillac Owners Fanatic
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    Your advice on the HT 4100 needed/appreciated

    I found a clean mid-80's Cadillac I am considering for a "fun" purchase. The car would be used primarily for weekend travel and some weekday use for short errands, etc. I like the older Cadillacs of the 80's, but I have read about the HT 4100 engine. I'm afraid to consider this car (it is exceptionally clean, with 60K on the original engine). What would you do? If I buy it, what precautions should I take? If you think I should not buy, are there cars in this period (late 70's, 80's, early 90's) you might recommend? Thanks!

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    Faded Crest's Avatar
    Faded Crest is offline Cadillac Owners Connoisseur
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    Re: Your advice on the HT 4100 needed/appreciated

    What year and model is the car? If it is an '85 front-wheel drive model, stay away. Not only did it have the less-than-desireable 4100, but the transmissions were terrible in 1985 front wheel drive models. They originally used plastic parts in the transmissions. However, most '85 trannys have probably been replaced by now.

    That being said, if you drive a 4100 lightly, keep the oil change and checked, keep it running cool, and use the factory-recommended coolant supplement pellets, you might be allright.

    I would not consider a 4100 for a daily driver, and especially not in a hot climate. But if the car has just 60k, it's probably okay as a fun/weekend car.

    If it is a small body Sedan de Ville you are looking at, the '88s with the 4.5 would be the way to go. Also if you want a small Eldo or Seville, '88-'91 is the way to go. If it is a big Brougham, years '80 and '86 and up are much better. But if you like the big mid '80s Eldo or Seville, you have little choice but the 4100.

    I have had a lot of experience with 4100s. I owned a used car lot from '94 to '01, and we sold dozens of them, and a ton of people blew them up. I know that there are conflicting opinions about this, but I believe slick 50 helps a 4100, too. After we started putting slick 50 in them as a shot in the dark, we had much fewer reported problems with the bottom end knock they are so notorious for.

    With all the other choices for vintage Cadillacs, the 4100 cars have really fallen off in price. You should be able to buy it cheap, regardless.

    Good luck.

  4. #3
    caddymark is offline Cadillac Owners Fanatic
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    Re: Your advice on the HT 4100 needed/appreciated

    Thanks for your great advice. The car is an 85 Seville slantback.
    I like those cars and also the mid 80's Eldorado. I also like the 89-91 Eldorados. Are these cars solid? Do they drive/ride as a Caddy should?
    Not interested in the large DeVilles (pre-85). Oh, yes, also interested in the 92 Eldorado (not Northstar). Thanks so much!

  5. #4
    Faded Crest's Avatar
    Faded Crest is offline Cadillac Owners Connoisseur
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    Re: Your advice on the HT 4100 needed/appreciated

    I also like the slant back Sevilles. If it's low mileage, it is probably still pretty tight. I'd like to have one. Just remember to keep that oil changed and coolant serviced. I've had a couple of those and always enjoyed them. '88-91 Eldorados are good cars, just a little small for my taste. '92 Eldorados are getting hard to find in good shape. '93s also had the 4.9 in the standard Eldo coupe, not the ETC.

    Good luck,
    Marc

  6. #5
    Faded Crest's Avatar
    Faded Crest is offline Cadillac Owners Connoisseur
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    Re: Your advice on the HT 4100 needed/appreciated

    I should clarify on my comment about bad transmissions... They appeared in Devilles and Front-wheel drive fleetwood models. The Eldos and Sevilles' transmissions did not have that problem.

  7. #6
    sk92 is offline Cadillac Owners Member
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    Re: Your advice on the HT 4100 needed/appreciated

    I'm driving a '92 Eldo with 201450 miles on it. It has held up well and is only now first showing signs of a coolant leak from the head. I have replaced the water pump 4 times.

  8. #7
    Tommy Deville's Avatar
    Tommy Deville is offline Cadillac Owners Enthusiast
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    Re: Your advice on the HT 4100 needed/appreciated

    Quote Originally Posted by sk92 View Post
    I'm driving a '92 Eldo with 201450 miles on it. It has held up well and is only now first showing signs of a coolant leak from the head. I have replaced the water pump 4 times.

    Ahhhhh the end is ni.

  9. #8
    awadecki is offline Cadillac Owners Enthusiast
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    Re: Your advice on the HT 4100 needed/appreciated

    caddymark:

    If the price is right, I'd buy the Seville, especially if it has the ribbed aluminum (later 85) rocker covers. Cadillac improved the 4.1 for the 85 model year, but some vehicles got through with 84 engines (like that in my 85 Deville). That being said, I have an 85 Deville for a daily driver, and it's stone cold reliable. I have, though, replaced the fuel pump (preventively--old one was getting weak) and alternator.

    However, if the price is not cheap, my best advice would be to find a 1980 or 1981 Seville as these cars had the 6.0L Cadillac V-8. This will provide you with more power and durability. The 1981 models had a cylinder deactivation feature that commonly failed, but those running around with it still working will be fine.

    1989-1991 Eldorados/Sevilles are solid cars. For the most power, purchase a 1990 or 1991 model. 1989s had 155hp, 1990s had 180hp, 1991s had 200hp.

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