I have a 95 Maxima and it has been leaking oil. I have isolated it to one thing ... or so I think. The leak is coming from the right side of the motor and drips onto the rear exhaust manifold, down the powersteering up then gets oil everywhere else. I have cleaned it off and found that the leak is above the powersteering pump, and seemingly below the head.

My Uncle is a Nissan Master Tech but lives in another state. I have talked to him about the leak and he has advised me of places to check. I have checked those places and found them to be dry. I told him that I had reason to believe it was coming from the knock sensor. He told me that there are a o-rings located behind the inner timing cover that are fed direct oil pressure. Often it fills the areas and seeps past the covers and the leak is often mis diagnoised because it spreads around outter areas with seals like the knock sensor. He seems confident that this is where my oil leak is coming from.

So that said I have 3 questions.
Has anyone ever experienced this before? My Uncle says its common in higher mileage Max's and that mine is, so I am inclined to believe someone here has.
Has anyone done this repair before (with motor in car)? It shows 18 hours in book time!!!!
Is there something else I can check? I may just be trying to avoid the obvious ... but I really dont want to do this job.

Oh I should mention that the car will leak onto the driveway over night. I believe it just takes it that long to make it down the block. It also leaks heavily when oil pressure is up.

Below is a diagram of the o rings (circled in red) and it kinda gives you an idea of the "possible" work ahead!

 

Why would you believe it's the KS? The KS is nowhere near oil

It's not that difficult to remove the outer cover in the car, and it's not all too much more work to remove the inner. You don't even have to remove the upper pan, though the proper way is to do so.

If you search, you'll find prior discussions on leaking rear cover o-rings.

 

Yeah really. Maybe you were thinking of the camshaft position sensor thats located on the timing cover.

 

my cousin had that exact problem. he had it fixed. it was the orings behind the TCC. While at it, since the block was torn apart and out of the car, he changed all gaskets and the TCC itself, as well as the cam gears, and water pump. True it is massive labor. for everything he had done it came to 26 hours. he paid a little over 2,000, nissan wanted 3500.

::EDIT:: the rear valve cover is also a known leaker, right beside the TC

 

I was definitely thinking valve cover myself. I also agree pmohr and 96nismoSE, there is no oil near the KS, although the CPS is a likely suspect. Just my .02 for just having done the outer cover and updated timing chain guide. . .

 

I'm in the rear valve cover leak club and I have oil in the places you've described.

 

Forget I ever said the KS it was a moment! I have considered strongly the rear valve cover but after cleaning it all off and letting it leak I found that there is nothing coming from that high up!

 

Pmohr have you done this yourself, in a home garage? I am mechanically inclined and have built motors in the garage and all, but this looks so tedious that I dont feel like leaving my other cars outside at night while I work on this. (high theft cars + South Fla = Calls to Allstate) Any idea on how long it should take and what did you use to hold that cams in time to remove sprockets?

 

have you try the uv liquid and a uv light to locate the leak??? my .02

 

I have not ... I no longer work in the automotive service industry so I dont have access to these things. I really think I just being lazy to do the work for the o rings. I guess I can call one of my old techs and barrow the light.

 

I've taken outer covers off in a32's & a33b's 5 times that I can recall, there might be others. It's a ***** but it's not THAT bad, I've never removed the upper pan to do it and I'm pretty sure I never had a problem, I say pretty sure because of the really really sketchy kid who I am pretty sure was just trying to rip me off, he never brought it back to get it fixed or confirm where the leak was. But anyways, if you do it I have one peice of advice:

Remove the passanger motor mount and the horizontal bolts for the front and rear motor mounts before you do anything else, this will let you raise the engine up and down to get at stuff, it will make the powersteering pump and some of the outer cover bolts SOOOO much easier.

Don't bother replacing the chains or anything, they never wear, but you MUST MUST MUST (I can't stress this enough) Use a BRAND NEW nissan tensioner for the timing chain, fill the crap out of it with oil and then push it back in just once and insert the pin (You'll have to do some practice tries and keep taking it apart and refilling it with oil until you get the technique down for pushing the plunger back in with all the oil in there. Once you do that and the pin is in, reassemble your timing chains to their respective marks, pull the pin, and FORGET IT. Have confidence in your work. Don't bother trying to turn the engine over to "Make sure it's right" It won't do you ANY good and just lets that much more oil bleed out of the tensioner and risk jumping timing a little more. Remember: Set the chains, pull the pin, and reassemble the motor.

Have fun, and if I were you I would make damn sure it's the cover and not the rear valve cover, allthough if it's getting into the engine valley it's probably the timing cover imho.

 

I'd plan for 2 days minimum. Also, there are flat spots on the cams themselves for holding them so you can loosen the cam gears, this is why you need to remove the valve covers for this job, there is a pretty good pic of this in the FSM located on Pmohr's website boredmder.com Also, no need to worry about holding the cams in time, you will redo that all anyways and you can move the cams a significant amount in either direction before the valves will tough the pistons, and even then you would have to be a real knucklehead to damage them. Assuming you put it at TDC before you start you won't have any problems with the cams turning a little while removing the cam gears.

 

^^^

Nice little fly by

Along with the tensioner i would replace the water pump(or at least the seals for the WP) and the front main seal(the half moon looking thing)

 

Thanks guys!!! I can never get this kinda help on other forums.

I will be checking the leak one last time for confirmation. If it is that then let the work begin!