There is a small amount of oil in the antifreeze overflow. I had a guy tell me that it is probably a head gasket. It doesn't miss at all so I was thinking of cleaning out the overflow and watching it for awhile and see if it is persistant. Maybe put some bars leak in it? I have had it work the other way around (antifreeze in the oil) but I don't have experience with this problem. Thanks for your help!

Ryan

 

Do not, repeat DO NOT put Bars Leak in ANYTHING! That usually causes more problems down the road then it fixes!

First, look at your dipstick and oil cap. Does it look like it's milky in color? Are you loosing coolant or oil?
If your 3.1 is the 3100 series engine, those are WELL known for having lower intake gaskets go bad every 80,000-120,000 miles if you stick with the original nylon LIM gaskets). So it may NOT be head gaskets, it might be LIM gaskets. You would have to do more diagnostics to determine.

 

No milky color in the oil. We just bought it last night and it ran for about 2 hrs straight with nothing in the oil. It just has some oil in the antifreeze overflow. Tonight I am going to clean it out and watch it closer. It is a nice looking car...just don't want to cause any additional damage to it. Thanks!

Ryan

 

x2 on that one anything of that nature will just cause problems down the road you can always do a compression check that will help confirm or deny the head gasket as a problem

 

Perhaps it's just residue from old/dirty anti-freeze.

But, if it really is oil, it has to come from somewhere. Usually you get coolant in the oil (not oil in the coolant). Keep an eye on it.

BTW - Is it a 3100 v6 (if it is, it will have 3100 imprinted on the top of the upper intake plenum)?

 

in 99 the only options were the 3100 or the 3800

 

Good to know. I know GM had a 3.1 and 3.4 that were different then the 3100 and 3400. Just not sure what years they used them.

 

I don't think we had to worry about the 3.1 any time after 94.

The 3100 was the base model for all Monte Carlos and Luminas from 95-99

The 3.4 DOHC was in 95-97 Monte Z34s.

The 3400 Became the new base engine in 2000.

 

Thanks for your help. I cleaned out the overflow tank last night and there was actually very little oil in there. It looked alot worse then it actually was.