Well, hell. Leaking oil after head gasket

Well, if you celebrate your successes you have to acknowledge your losses, too.

My XJ40 with the used replacement engine is back in, and you can see from my post yesterday that she started right up. That’s the success.

The loss. I have an oil leak. Emanating from the head gasket, at the back of the block. I’d hoped it was only the valve cover gasket which also had a leak, but after solving that issue, there is still a significant leak there. It’s not the half moons, it’s not the cover plate. It’s the head gasket.

The cause? I don’t know.
I used acetone to clean up the both surfaces before mating. I used spare blank bolts to line up the gasket. I cleaned and blew out the holes. I cleaned the bolt threads. I torqued to 45# plus 90 degrees.
I still have a oil leak and now it looks like I have to do the whole thing AGAIN?
I’m tempted to try to tighten an extra 90 degrees and see if that works but there is pretty much no chance it won’t keep leaking, is there?

Try 30 degrees: if no joy, head will need to come off.


Update to the saga…
One detail I did not mention before was that I had another disturbing development after the headgasket job - the #5 had a odd “pulsing” of the sparkplug that could be felt by touching where it contacts the valve cover. And upon inspection, the plug was damp with water. UGH.

Per Paul’s suggestion, I removed the valve cover and made a 25-30 degree tightening of the bolts. Cleaned the cover up and remounted it, careful not to spill any oil. Then restarted.

No pulsing, no water. But after a few minutes, I had the smoking of oil at the back emanating from the cats. I thought it was oil dripping on the cats, but realized it wasn’t oil burning but exhaust.
I had one of the replaced copper nuts on the headers that wasn’t tight enough. Tightened it up.

Now no smoke and running great! Best of all, I think my head gasket job is a success.

Does anyone want to by the replacement head gasket and 14 new head bolts I just paid $300 for a job I don’t need to do now? :wink:


Keep’em in stock: they wont get cheaper, and you might need them!

This I know to be true. I’ll just put them in the box with all the other odd and ends from the other engine for the next owner.