can anyone tell me if the 1985 el dorado biarritz' came standard w/an aluminum engine, or ..?? thanks for your time!
rebecca

Hi Rebecca, welcome to the board. The 85 Eldorado came standard with a 4100 aluminum V8. The 8th digit of your VIN number should be the number 8.

Hi! and thanks for your response... I was afraid of that. I have never really heard a good thing said about those engines..but then again, in my 80 Eldo ..or was it my 81??(I don't remember which one), but one of my prior Eldo's had the "4-6-8" engine...and it was the best running car I ever had!! (shoulda kept it)..Do you know if that engine was aluminum??..just curious! and there had to be some good "aluminum", right? maybe? any opinion?
thanks again! rebecca

Your older Eldo had a 368 cu. in. V8 and it was an ALL iron block and heads. And yes they were great engines!

The aluminum engines aren't really that bad, as long as you got a good one and it was maintained. The early ones were just a little sluggish.
The old Cadillac 8-6-4 engine was cast iron. The idea worked good on paper. It may actually come back in one form or another.

The 368cid 8-6-4 engine seems to work great for some, and not so great for others. In my search for Caddies, I avoided the 368, not because some of them were multi-displacement, but because I wanted at least a 425 to work with. The 249cid HT4100 can be pretty solid IF and only if it's been maintained well, like regular coolant changes and coolant additive use. The 4100 isn't powerful though, especially for ~3600 pound cars.