Is it really as bad of a motor as everyone says it is? Seems to be a strong motor. Not fast but runs pretty smooth. I just got the car about a week ago and it seems fine. It has 79,000 on it.

 

at the beginning, they were infamous. 20 years later, the bad ones have all died.
however, if the coolant is not changed every two years or less, and add the supplement, expect something to go wrong.

you just got the car .. go to our FAQ and read about coolant and headgaskets, change coolant yesterday.


also check these out

The BEST car Cadillac ever made is the ..
https://www.cadillacforum.com/m_9438/tm.htm

MY Cadillac has more miles than yours thread ..
https://www.cadillacforum.com/m_12353/tm.htm

Average age of our Cadillac owners
https://www.cadillacforum.com/m_931/tm.htm

Why you should change to coolant the day you buy the Cadillac
https://www.cadillacforum.com/m_7193/tm.htm
https://www.cadillacforum.com/m_7388/tm.htm

CODES .. We need CODES to help you.
https://www.cadillacforum.com/m_18197/tm.htm
https://www.cadillacforum.com/m_17425/tm.htm
https://www.cadillacforum.com/m_11904/tm.htm

Cadillac FAQ MENU
https://www.cadillacforum.com/m_6733/tm.htm

Cadillac Technical FAQ section
https://www.cadillacforum.com/forumid_64/tt.htm

Cadillac Allante FAQ
https://www.cadillacforum.com/forumid_83/tt.htm

The Cadillac Allante Pub - Allante not needed.
https://www.cadillacforum.com/m_21055/tm.htm

Allantesource.com Allante PROCEDURES MENU
https://www.cadillacforum.com/m_18287/tm.htm

Hobby Corner
https://www.cadillacforum.com/forumid_60/tt.htm

Cadillac History
https://www.cadillacforum.com/m_6356/tm.htm


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What is this supplement youare talking about? Thanks for the help.

 

Well I found out what it is.

 

you car has or had a sticker on the radiator referring to the GM "supplement"
but the one on the link is the same stuff and made by the same company.

glad you found it

 

I just got an 86 Deville. The motor is having lots of problems with knocking.I think the crank shaft or somethingis going out. I would like to do a motor swap!Are there any good ones out there for this car???

 

Any good ones? lots and lots, on cars made after .. 1985 .. I believe ...

But if you want better, look for an Allante 4100, 1987 / 1988, more hp, and more reliable.
The Allante 4100 is identical on the outside, high performance in the inside.




.

 

sounds like what i needed to know thanks bro!

 

To add one final note, the vast majority of 1982 & 1983 4100's did not make 60,000 miles without severe bearing knock or complete engine failure. Complete engine failure was known to occur in as few as 30,000 miles.

Cadillac replaced hundreds of thousands of these engines under warranty; so many, in fact, that it was common to see bad HT4100's stacked like cordwood in service departments across North America.

What we see surviving and on the road, are most likely the warranty engines of 1984 to 1988.
The Allante 4100, being 1st made in 1987 was not afflicted with the malady.

 

Where would be the best place to find a good Allante motor?