Hey guys I'm working on my buddies xj for him. It's a 1987 with a 4.0. It runs good but it has milky residue on the dipstick as well as condensation and some residue on the oil cap. But when I drained the oil I found no evidence of coolant or residue. I've never done a head gasket so please help me out and tell me if it might be something else cause coolant residue on the dipstick. Thanks guys!

 

What exactly are the symptoms or issues that you're working on it in the first place for?

 

Do a compression test on all cylinders, could just be condensation on the dipstick but it very well could be a leaking gasket. Also check the exhaust when it's running, if there appears to be more water vapor than there should be that will give you more info.

 

Does it have coolant loss for no apparent reason?

 

There were no symptoms really besides that after shutoff steam would roll out of the exhaust. It ran and idled the same. He was loosing about a gallon of coolant every two weeks.

 

Yes and no. The radiator has a leak that is quite obvious so I don't know how much is getting into the cylinders

 

I pulled the valve cover and found nothing that would indicate a big leak in gasket. There wasn't even a drop of coolant. Anyone have any ideas of what else could be an issue?????? I'm doing a compression test tomorrow

 

Cast iron heads dont crack gaskets for the most part. If you find that the head gasket isnt cracked I would look real close at the head. I did a head gaskets on a Chevy and found the head was cracked so every intake stroke. It would suck water in.
Run a compression test.

 

Run it without the rad cap on and look for bubbles, or even exhaust fumes.

 

Fix all coolant leaks first, starting with the radiator.

I can assure an earlier poster that cast iron heads do crack and head gaskets will blow between the head and the block.

 

Could I run a compression test with the oil already out or should I top it back off? I really don't think it's a blown head gasket because my only real clue would be the cream on the end of the dipstick which from what I read is common in short trips and in cold moist environments. I'm leaning more towards condensation but I'm still gonna run a compression test.

 

If you still have the used oil, pour it back in and run the compression test.

 

Yea, I'd rather do a compression test on an engine that is at least warm. One reason being the end gaps of the rings is smaller. You could even do a second set ot numbers after adding a couple tablespoons of oil to the cyls, a "wet" test. A low one comes up wet, rings, no improvement, valves. (not for moisture, just because you are there)


Has it been sitting? Some amount of moisture might be normal....might check the CCV system. The rear tube to the manifold, and the CCV orifice should be clean and clear. The front 1/2 inch tube to the air box needs to be free as well. I'd bet some of those after-market filter deals some run just get mucked/plugged up inside where you can't see it. Don't really know though.