I just changed the oil in the 99 Cherokee I bought last week. When I drained the oil into a pan I noticed there were bubbles (a good number, but not a lot) evenly distributed throughout. The oil otherwise didn't seem milky or too light-colored, but this is only my second time changing my own oil. Also, the engine was completely cold when I drained it.

I'm worried because I've also noticed coolant disappearing from the overflow tank (a good amount, almost a gallon now) and I haven't located the leak yet. The engine is running fine and not overheating. I definitely haven't seen any leaks onto my garage floor, though.

Does anyone have any thoughts? Could a gallon of coolant disappear into my oil without it being really lightened? What else can I check before going to a shop and dropping a bunch of $$$?

 

If there was a gallon of water in your oil it would be very milky looking and when you changed your oil you would have seen alot of water before the oil,if the engine was cold when you changed it. You can have bubbles from just changing the oil.
The best thing I can suggest is to either have someone pressure test your coolant system or buy the tool and do it yourself,if you are concerned it could be a leak,they are about $60,it will tell you if you have any leaks including a headgasket leak.

 

my headgasket was leaking and it was running fine but there was not any water in my oil .

 

does it smell sweet when it running? smell your exhaust and it will have a sweet smell (kinda like maple syrup) when it running. that would mean coolant is burning in the engine.

 

I'm going to have it pressure tested. Thanks for the responses guys. I was thinking that the water would have to drain out first but it definitely did not. I think it's still a possibility that I'm combusting the coolant though, so I'll check for a syrup smell. I'll have to drive it away from my house though, since I live right near an iHop.

 

I had the same issue and it was the headgasket that was leaking,I found it by doing a compression check and found two cylinders low.