: Wow, this stinks

05-12-05, 06:18 PM
I get this awful smell through the inside ac vents of my 96 Deville Concours when it is bringing in outside air, like burnt oil. Also when I turn off the engine in the garage it smells bad. I took the car to the mechanic and he says I need new seals and the engine has to be taken out to do it. It also costs around $2000 to repair. They also said this isn't unusual. Is there anything I can do to solve the smell problem? I can deal with an oil leak but the smell is awful. I do have 127000 miles on the Cadillac but I have had many other vehicles with more miles than that and none of them have these high priced repair bills. Any help would be appreciated.

05-12-05, 10:07 PM
Exactly what "seals" are leaking? Where is the oil coming from?

05-12-05, 10:35 PM
Supposedly the oil is leaking from the seals between the main parts of the block. I have had 3 mechanics including a dealer look at it. The dealer said $2800 because they had to remove the engine, the independent Caddy repair shop said $2000 and they had to remove the engine and my regular mechanic that doesn't do Northstar said he couldn't tell where the oil was coming from after putting a dye in it. I looked and could only see it was oily several places but I didn't know exactly where I should be looking.

05-12-05, 11:23 PM
There is a good possibility that the case-half seals on your engine are leaking, as you've been told. If that is the cause of your problem, the quotes you're getting are in the ballpark.

There is also a possibility that alot of your oil leak could be coming from the oil pan bolts. Here's the deal - the lower engine case is aluminum, and can become porous over time. If it does, oil can seep through the case into the oil pan bolt holes. Once it gets to the bolts, it runs down them to the oil pan lip, spreads out, and spills over in sheets down the sides of the oil pan. From there, it can drip down on to the crossover exhaust pipe that runs under the oil pan and make the smoke you're smelling.

Before you put out the money for the case-half repair, you may want to ask your mechanic to pull a couple of the pan bolts and see if they are coated with oil. They should not be. If they are, the bolts and holes should be cleaned with brake cleaner, coated with thread sealer, and reinstalled. Then check the rest of the pan bolts.

I've read that case-porosity was a problem that led GM to adopt a pressure-casting method for the 2000 and later lower-case halves.

I was able to reduce the oil leak on my 93 by about 2/3 by sealing the pan bolts. I do have 1 spot where the case-half is leaking, but it was not the major culprit for me.

Good luck with your problem.

05-13-05, 07:17 PM
Thanks for the info. I think I read something about the porosity issue. I will take a look and see if they are oily. When the bolts are removed and re-installed one at a time are stripped threads likely in the aluminum? I have heard this is also a big issue.

05-14-05, 10:32 AM
That shouldn't be a problem.