art

I replaced my rear seal, and it still seems to leak a bit after the engine shuts off. It took a while, but there is a drip down the back side of the oil pan. I'm quite sure it is not the oil pan gasket. It does not seem to leak while running, but I've only run on jackstands for 10 minutes at at time.

Does a new seal take some time to 'break in'?

Thanks,

Art

'86 na

John.

Usually not......however I would give it some time. Best practice when installing a new seal is to install the seal at a slightly different depth than original.....this gets the seal on a clean part of the crank, since the old seal has usually worn a groove (slight) in the surface. Considering the labor involved to re-replace, I would not worry about it unless the leak is excessive.

art

I should have mentioned that the crank was in good shape, so I don't think that is the problem.

Is there apotential leak path around the bearing cap?

thanks again,

Art

art

I've done more looking at this and it seems very strange. The leak does not seem to happen while the engine is running, but it leaks long after it is shut off. I am still not certain where the oil is coming from, but the area just below the seal but above the oil pan gap has oil collected on it before it drips down the back of the pan.

Anyone out there with experience?

Bryan

Since you're asking for people with experience I though I'd take a complete shot in the dark for you.

Try the following - as soon as you shut off your engine, pull out the dipstick. Then see if the leak happens. My theory is that you're crankcase is slightly pressurized after you shut off the car and the pressure is pushing oil past the seal. The crankcase gets pressurized while the engine is running of course, but there's the whole PCV system to deal with it. But after you shut off the car, there's no longer vacuum drawing out crankcase vapors and for whatever reason your crankcase is building up pressure. I'm not sure, but there's probably some sort of valve somewhere that prevents vapors escaping into the atmosphere with the car off, and/or (if you have a turbo) from boost pressure going into the crankcase. If this valve is getting sticky perhaps it's letting pressure build up.

Again, no experience with this particular aspect of the 944, so let us know what happens.

Bryan

rplencne

Maybe the gasket on the backside of the cam assembly ?

-Bob P.

art

I tried the venting idea, no dice. Good thought though!

It isn't coming from the cam end plate either. I'm going to wedge a piece of oil absorbing mat'l between the flywheel cover and oil pan to catch the oil.

I guess the reason I'm so obsessed with this is that it is the main reason I took the engine out. I did find plenty of other reasons once it was out, so that is some consolation. I also have a 914-6 that has a similar leak around the #8 bearing which can't be fixed unless the case is split. That engine has leaked since it was built(not by me) and it makes a major mess on the engine. Oh well.

Thanks for the input,

Art

art

I got up to look at the seal with a small borescope and found that it was leaking around the OD of the seal. I may try to devise something to press the seal in a little further or else drop the engine again.

Art