Flybynight

Hello, first time post. I've been searching the forumn for advice...figured I'd ask. I have a 2000 XJ with a 0331 head. The rear-main seal is leaking a bit. Recently I noticed what appeared to be a bit of coolant (milky tan) in the oil spot under the normal rear main leak. This only developes after the truck is sitting for a few days. At all other shorter times the oil spot appears to be normal oil. There is no milky residue under the oil cap, dipstick, or in the radiator. Temp is always stable at 210 and oil pressure is normal. I have not done a pressure test. I'm assuming the head gasket is blown or the head is cracked. Should I even bother digging any further or just replace the head with a Clearwater and not have to think about it again? The coolant coming from the leaking rear main doesn't sound right. My coolant has been staying at a constant level. Any advice is appreciated.

extrashaky

If the head is coming off to replace the gasket anyway, I would just replace it with a Clearwater head and be done with the stupid thing. The 0331 head is a curse. What would really suck is to replace that gasket, put that head back on and have to pull it off again in a few thousand miles because the thing decided to crack after all.

Firestorm500

Are you sure that's not condensation getting into the oil drip?

bigbadon

If your not losing coolant or overheating then head is not cracked.

Crazy 8s

That is actually not true. The head can certainly be cracked and not losing coolant or overheating. The same for a blown head gasket, which can be blown while not losing coolant or overheating.

I blew a head gasket in a straight 6 and it lost most compression but did not overheat or lose coolant. It failed in between coolant passages, and a crack can exist in between coolant passages.

bigbadon

He has not stated any symptoms that indicate a cracked head.

Flybynight

Thank you all very much for the replies. I'm going to keep a close eye on the coolant level. I'm going to change the rear main seal so I will get a good look inside the pain for signs of coolant. Also, going to remove the rocker cover and inspect for a crack. For those of you who have seen the head crack, is it obvious?

bigbadon

It cracks between 3&4. Google 0331 images to see it. It can crack on combustion side too and that can cause overheating. You can test coolant for hydrocarbons with a kit sold at auto part stores. A oil sample sent to Blackstone labs can test for coolant in oil. I still think you may be over reacting.

Firestorm500

Yeah, me too. Unless you're just bored and looking for something to do, if it was my Jeep I'd leave everything alone for now and just drive it.

I've learned to accept that a 15 year old (or older) vehicle isn't going to be perfect. I take care of the safety, reliability, and performance things but a little drip now and then doesn't bother me.