I enjoyed my time driving and tuning on my car this summer, but right now the car is down and out for a while. I've had a pesky oil leak around the rear main that I can seem to resolve. I've change out rear main seal and oil pan gasket with negative results. I think I might have scarred up my crank around the seal trying to get the old one out. I'm getting to the point that I can't work under a car anymore because of buldging discs in my neck---probably caused by too much working underneath my car.

Then my head gasket gave out for some unknown reason and I hate the unknown. There is nothing that jumps out at me to why the gasket gave out-which hopefully means that nothing is wrong and I just had bad luck with this gasket. I ordered a new Nismo gasket for 150$ two weeks ago and still haven't seen it yet. I am going to take the head back to the machine shop that did the work on it to check for flatness. Good new looking at the head is that I didn't see anything that looked like damage from detonation.

So my list for this winter is getting bigger, but the list has too many items that I am redoing-which sucks. I am going to have to find a helper so i don't over do my neck issues. I told my son to try and find an older high school kid that is a motorhead and wants to make some money over the winter. I figure under direct supervision I can get some help with the hard labor stuff and maybe we can teach each other some stuff. Too bad my son isn't into the cars like me, but that's okay he is a straight A student and an athlete so his time is limited.

Well I probably cried enough:cry:--time to come up with a plan.

Didn't you also replace the side seals on the oil leak?

Yes I did

I thought so. Can't believe it still leaks

I had a problem on an engine that leaked. After driving it hard enough, I blew off the oil filter gasket and poured out all my oil. Turns out the oil leak was caused by too much pressure. The oil pressure relief valve was stuck closed, giving much higher oil pressure. After fixing that pressure was normal, and it quit leaking.

Just a thought, have you checked your oil pressure with a gauge?

--Justin

Oil pressure relief valve????? I'm curious but also stumped- can you elaborate on this please?

Justin, just did a search- thanks for the idea. I had checked my PVC system for excessive pressure, but never crossed my mind about the bypass valve. Of course that would mean that oil has been bypassing my filter-YIKES !

I hope your right though and I won't have to pull the

Motor to screw with that rear seal again

I've had a motor (Ford 289) where I had more problems than it was worth and finally just gave up on it and replaced it. You might just want to keep your eye open for a good used motor. The Z motors are very plentiful and inexpensive. They are very bullet proof motors too. I found the motor that is in my car for $300. Perfect compression, no leaks, runs like a champ.

Actually when the bypass is stuck shut, it supplies full pressure through the filter and through the entire engine. In my case, it was on my VW beetle and the pressure relief valve was at the last crank bearing. I was told that with the Bug engine, excessive pressure could score the main bearings, due to the way they are drilled through the crank. Like others have said, the Z engines are very durable. Hopefully it's something simple.

-Justin

Update: I just looked in my 260z manual and there are two oil pressure regulating circuits.

1) At the filter there is a bypass for when the filter is plugged, I believe this also bypasses the filter when the oil is cold.

2) In the oil pump itself, there is a non-adjustable oil pressure regulator valve, this is what is supposed to regulate the oil pressure. In the Engine Lube section, it details the operation of it.

Hope this helps - Justin

Edited October 24, 201113 yr by buysell