Two years and about 16,000 miles ago I had a rebuilt head installed on my 90 XJ40. Now it looks like my right rear is leaking oil at the head.

The other possibility is the rear plate on the head. Apparently it is a one piece plate with a split gasket arrangement. Oil behind one part and coolant behind another. I tightened up the top 4 bolts but due to the placement of the EGR piping, I can't even touch the bottom two bolts.

From underneath it looks like it is leaking at the head but because it is a slant (to the right) if it were leaking out of the rear plate, it would roll down the slant.

If it is the head I am guessing that there is no re-torque like on the BMW forums. I would need to loosen and re-torque and that would be a messy thing.

I wonder if the mechanic took the bolts to torque and then plus 90 degrees and did he do it in the correct order? I hate when I don't do my own work!

The leak isn't that much but it does roll onto the hot exhaust pipe and smells.

I had posted this on tech help and didn't get any answers. Maybe it was the wrong place to post.

90 XJ40

1990 XJ40

 

Reading quite carefully what is going on I am thinking the cam cover gasket and especially the 2 "D" rubber seals at the rear.

The slant of the engine is decieving as my AJ16 had me stumped for a while and it was the gasket at the very corner of the low side rear edge.

The head gaskets mainly were an issue on the 3.6ltr engines and an update gasket came along with the 4ltr engines.

The head bolt issue is a real worry, coz if he has not done it properly you will need to get "messy" as you said. I thought that the head bolts on these engines were meant to be replaced after each use, BUT, I may be wrong.

 

You are correct about the cam cover leak being deceiving.

Normally that cam cover and "D" seals are the culprit but not this time. I rubbed my finger around the entire range and tt was dry all around the entire gasket(s) range. Just to be sure I installed a new set.

The head bolts are not stretch bolts and can be used again. But unlike the BMW forum where people re-torque the heads for oil seeping, the concensus is that it won't work on an AJ engine. The reason is the torque to the number and then go 90 degrees. The 90 degrees would leave you at an unknown torque figure and if I would go forth from the current position of the bolts, I could break something. So yep....I would need to unscrew the head bolts to start over and that would be messy.

I'm still thinking that the cover plate at the rear of the head may be the culprit. There are 6 bolts on that cover plate, four bolts are easy access but the bottom two are knuckle breakers. I removed the EGR pipe from the EGR valve and did get enough clearance to snug up the two bottom bolts. It still drips oil, I get an oil burning smell but maybe not as much. If it is the gasket on the cover plate I will need to remove the entire EGR pipe. I'm trying to figure out if I need to remove the throttle body to remove the EGR pipe from that side of the engine.

I want to find this leak because I am tired of putting down and sweeping up oil drier.

 

OK, at least you have done some good diagnosis, and that is important.

Cant help with the EGR pipe, as we dont have that stuff here, lucky I believe.

Someone will pop up with suggestions, but I reckon it will be a bugga of a job, BUT required.

 

Remove the throttle body and other hoses and such will give you a lot of room to work.You will have to get a large open end wrench for the coupler (you dont have much range when turning I cut the wrench in half and made it easier)