Oil in coolant
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Most likely it is not oil in the coolant, Its the Dex Cool GM put in there for coolant. It has a brown mud look to it and it is very common on a car that needs a coolant flush. You will never get it all out either. In my project 96 I flushed the engine while it was out with a hose and the radiator and I replaced all the stock hoses and changed the coolant twice and I would still get some of the old brown stuff in the over flow.
The biggest problem it will cause will be sediment in the radiator. I have seen radiator half full of the mud. With the radiators that full over heating becomes a problem.
Its been pretty common for people to think its oil in the coolant but your 3800 has no pressurized passages through the heads or intake like an over head Cam engine would. The only way to get oil into the coolant would be a crack in the block/heads or intake. That would allow oil into the coolant when the engine was cold but it would also allow coolant into the oil when hot. This would render a engine not savable in a matter of hours. If your oil is clean or even black your good. If your oil is a brown milkshake you are screwed.
As long as your oil is still oil just flush your coolant and watch the heat. If the engine is running out of spec hot either keep flushing or replace the radiator.
The biggest problem it will cause will be sediment in the radiator. I have seen radiator half full of the mud. With the radiators that full over heating becomes a problem.
Its been pretty common for people to think its oil in the coolant but your 3800 has no pressurized passages through the heads or intake like an over head Cam engine would. The only way to get oil into the coolant would be a crack in the block/heads or intake. That would allow oil into the coolant when the engine was cold but it would also allow coolant into the oil when hot. This would render a engine not savable in a matter of hours. If your oil is clean or even black your good. If your oil is a brown milkshake you are screwed.
As long as your oil is still oil just flush your coolant and watch the heat. If the engine is running out of spec hot either keep flushing or replace the radiator.
How can I tell if its DEX-cool and not oil. I just purchased a 1998 Chevy Camaro and upon inspection the mechanic is telling me it looks like oil in my coolant. What can I do to be sure before i invest un-needed money into something that may not be the issue. sorry i know this is an old post.
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What is he saying it needs? Do you have coolant in the oil also?
If your coolant system will hold pressure there are no leaks, you can borrow a pressure tester from a chain parts store. Like I said above oil in the coolant is a overhead cam thing. A 3800 would have to get extremely hot (over heated to the point the motor froze up) or extremely cold (cold enough to crack cast iron) Search Youtube on how to pressure test your coolant system. If you system does leak pressure I would still bet it is more likely a intake gasket, hose or water pump issue. If it is a very slow leak like it takes hours to bleed down I would still consider the car drivable it just a warning of something coming.
So newer mechanic that work on overhead cams do see oil in the coolant a lot. Most of the time it means a bad head gasket. But those cars all have 50-60 PSI of oil pressure passing between the block and the cylinder head. GM non-overhead cams just have oil flowing from the top of the engine to the bottom of the engine due to gravity. NO Pressure. Most of time while the engine is running you have up to 16 PSI of coolant pressure. So for a head gasket to cause oil in the coolant the non-pressurized oil that is just falling back to the oil pan would have to push past 16 PSI of cooling with no coolant entered the oil chamber. If you truly have oil in your coolant your motor is not worth trying to fix. Just finding what cast iron part has a crack in it would be a complete tear down of the motor.
You should note I have been telling people on this site for years if not a decade that the oil in the coolant is always a misdiagnoses common on all the 90-early 2000. I have yet to have someone come back and say I was wrong. Also just about every camaro I have looked that is not well maintained (coolant flushes every 5 years) Looks like it has oil in the coolant. Coolant in the oil causes a chocolate milk shake looking film on top or mixed in the oil. If you have any of that you have a whole difference set of issues that need addressed ASAP .
If your coolant system will hold pressure there are no leaks, you can borrow a pressure tester from a chain parts store. Like I said above oil in the coolant is a overhead cam thing. A 3800 would have to get extremely hot (over heated to the point the motor froze up) or extremely cold (cold enough to crack cast iron) Search Youtube on how to pressure test your coolant system. If you system does leak pressure I would still bet it is more likely a intake gasket, hose or water pump issue. If it is a very slow leak like it takes hours to bleed down I would still consider the car drivable it just a warning of something coming.
So newer mechanic that work on overhead cams do see oil in the coolant a lot. Most of the time it means a bad head gasket. But those cars all have 50-60 PSI of oil pressure passing between the block and the cylinder head. GM non-overhead cams just have oil flowing from the top of the engine to the bottom of the engine due to gravity. NO Pressure. Most of time while the engine is running you have up to 16 PSI of coolant pressure. So for a head gasket to cause oil in the coolant the non-pressurized oil that is just falling back to the oil pan would have to push past 16 PSI of cooling with no coolant entered the oil chamber. If you truly have oil in your coolant your motor is not worth trying to fix. Just finding what cast iron part has a crack in it would be a complete tear down of the motor.
You should note I have been telling people on this site for years if not a decade that the oil in the coolant is always a misdiagnoses common on all the 90-early 2000. I have yet to have someone come back and say I was wrong. Also just about every camaro I have looked that is not well maintained (coolant flushes every 5 years) Looks like it has oil in the coolant. Coolant in the oil causes a chocolate milk shake looking film on top or mixed in the oil. If you have any of that you have a whole difference set of issues that need addressed ASAP .
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