Another oil leak

[Mike W.]

Seems there's a few of these out there right now, but I haven't seen my exact issue discussed.

03 QX4, 3.5 engine

It leaks if it's parked uphill from the back of the engine area. I've crawled under there but haven't been able to see anything, but further in the air with more light might help. It did not seem to leak on vacation this past summer when parked on level ground, nor is the underside coated in oil as it might be if it was leaking while driving, but I have seen engines that didn't leak while running but did when shut off. It's been parked where it's at for about a week, I'd guess about a 10% grade, more than a little bit, and it's got a spot below it about 7X10". Not small, not just a drop or two. It's apparent the pan has been resealed before, it's got silicon squeezed out all around it but does not appear to be the cause, unfortunately it's further back.

So. Sump, AKA in Nissan speak upper oil pan? Looks like an absolute b**** to R and R. Crank seal? Might it not be easier from looking at the manual to just pull the engine rather than do everything it says to just do the sump? Of course if I'm that far in I might just do the rings to try to cure the oil consumption. Ahh, mission creep. But it only seems to be a problem parked uphill.

Or is there something else that might be a whole lot easier if I'm lucky?

[rgk]

Upper pan, valve covers, oil cooler or rear main.

[brickbox]

I think you should be able to rule out the oil cooler and VCG pretty easily. Perhaps, get underneath and try to clean the area up with brake cleaner?
Then let the car sit for a day or so (if you can) to see if its leaks. Then run the engine where it is parked for about 10-15ish mins and see if it drips??

From what I've read/seen, if its leaks after the vehicle is shut off, that's indicative of the upper oil pan seal, If instead, it's leaking while the engine is running, it's indicative of the RMS.

[Mike W.]

VC gaskets were done just before I purchased it, but since not by me it doesn't rule it out completely, but I don't think so. Isn't the oil cooler towards the front? I haven't been under it much since I heard about it so I haven't really checked it yet. It does seem to leak mostly/only when shut off and parked uphill. Doesn't look like much difference in the amount of work required to either do the sump or the rear main but it does look like it might be easiest to just pull the engine. I mean the manual speaks of pulling the front diff, hoisting up the engine etc.

Maybe I just just learn not to park uphill when it's full of oil, which given how much it consumes shouldn't be difficult.