oil leak

[zhead240]

could this be caused by fan clutch leak? i did a search and tested fan with cardboard and it stopped fan, thus not siezed. when rev engine there's not a whirlwind of noise or wind. i'm thinking fan clutch is ok. i noticed last fall just before i put in storage that there was specks of oil on underside of hood but not there everytime i drove it. i put cardboard under car during storage and no leaks. doesn't use oil.( although hard to tell because i change oil once a year before i put it away and drive under 2000 miles pure season.) never have to add oil. i can't recall if this gunge was on the motor when i bought it or if it's gradually accumulated over the last 3 summers. tiv

[Arne]

Since the pulley is not coated, that would seem to eliminate the fan clutch as a possibility.

[MikeW]

Could be a slow timing chain cover gasket leak. I'd clean it all up really good with some de-greaser or a pressure washer and then keep a close eye on it. It will be easier to determine where it's coming from the sooner you catch it.

[d240zx2]

You could also find some kind of oil-compatable dye that would show where it's leaking....

[DeesZ]

I'd lay odds on it being an oil leak from the fuel pump (no, not fuel leak). Mine did (does) the same thing at the same place, and it took a while before I could track it down. Look at all of the crud build-up under and on the bottom of the fuel pump. Suggestion: clean up that area very well, and especially the bottom side of the fuel pump, until it's spotless. Drive it for a few miles and after you park it, run your finger on the bottom side of the fuel pump in the area under where the lever passes through..... I'll betcha you get about one drop of motor oil on your finger.

I have not swapped out the fuel pump yet on mine and I get a drop after a bit of driving. I guess that the pivot pin area or somewhere around there inside is leaking and working its way through to the little weep hole/vent on the pump. This leak was discussed a while back somewhere in the archives and I do not recall anyone suggesting what a fix (other than another pump) would be. Please let us know what you find! If it's the same problem, then there are two of us looking for a fix (short of replacement).

[enzo250GTO]

G'day from down under,

It looks like you are using a mechanical fuel pump. I think that if the diaphram has a hole in it ( old and worn ) the pump can lose engine oil through the breather hole. Higher revs more oil. Hope this helps. Regards David.

[fuzze]

Seem a common problem , I have the same leak at the weep hole .

Can the diaphram just be changed out or do you need a new pump all together ?

thanxz

Chris

[beandip]

One of our club members bought a diaphragm from our Sponsor Nissan dealer just a couple of weeks ago. If you have a OEM pump , with the series of screws all around the top , these can be rebuilt by a new diaphragm. Gary

[DeesZ]

Hi, Gary.... I thought about the diaphragm replacement as a solution, but discounted it because all of the 'problems' with the oil seep seem to be between the diaphragm and the head. In other words, I was thinking that the problem/leak was 'before' the diaphragm.... does that make sense? Maybe I'm looking at the situation wrong or backwards. Was an oil leak solved with a new diaphragm by your club member?

[Arne]

The diaphragm is for the pumping action. The pump attaches to the head and is sealed there by a pair of gaskets on either side of the insulator. Might simply need new gaskets.

Gary, thanks for posting about the diaphragm. I didn't know it was still available. I will have to get me one just to have, since I still have the original pump.