Bill 993

My 1996 993 with 26K miles had it's first oil leak. The leak is at the top of the cylinder where it mates with the head. The photo is taken from under the Porsche showing the exhaust header and the head is towards the left and bottom end on the right. Both the rear cylinders (closest to rear bumper) are leaking the same way. The leak isn't bad enough to drip and has developed over the last 6-months. My Porsche burns a qt. of oil every 1,100 miles (hasn't changed in last 10K miles).

Any opinions? Serious? Thanks in advance for any help.

993,951,944

Bill:

Finding the correct location of a small oil leak can often
be difficult. Gravity and airflow will influence where
oil accumulates. The leak may not be from the cylinder
head, but of some other source less consequential.
Although, I would have it checked out.

Perhaps Steve W. could chime in with a few
diagnostic or repair suggestions.

My C4S with 72K miles has a leak that's similar in
appearance of which my mechanic indicated it was
quite common and not anything serious. It doesn't
drip, but the oil does contact the exhaust manifold
making a burning candle smell that only enhances
the driving experience. Like many other Rennlisters,
You could spin this leak into something positive:

"I love the smell of 993's in the morning"

chris walrod

It maybe something simple, like the crankcase breather cap etc.

You may want to get a 'bend-a-light' (small light on a flexible extension), some small mirrors on a telescoping stick and poke around on top of the engine. Maybe you'll see some wetness and give you a better idea whats leaking.. Sometimes you can peek through the fan with this type of flashlight and mirrors...

Steve Weiner-Rennsport Systems

Hi Bill:

David offers some good advice,.....cooling airflow tends to blow any small oil leaks everywhere making it tough to pinpoint the source.

Aside from valve covers and chain boxes, minor cylinder head leakage and case through-bolt O-rings are the most common sourse of oil seepage. I'd suggest that you get a can of carb cleaner and spray that off as well as possible to see where its coming from.

One can see most of the case through-bolts/nuts by removing the cooling fan and looking at the top of the engine case using a good light.

If the top of the engine is dry, I'd suggest retorquing the heads to start.

Lastly, is your engine undertray still in place?

Bill 993

Steve,

Thanks for the info. Yes, the engine shield has long been removed. Does having the leak on both sides of the engine (rear cylinders) give another strong clue?

Bill

Steve Weiner-Rennsport Systems

Hi Bill:

Not really,.....I think thats mostly coincidental although there is a through-bolt just above the 1 & 4 cylinders.

I would suggest that you pull the fan, clean everything up and see what goes on here. Please let me know what you find.

Bill 993

Steve,

Ok, your suggested plan of pulling the fan sounds good. I will likely watch the leak cloesly and wait for the 30K service (early Summer 04 timeframe) when the rotor caps, plugs, plug wires, and fan belts (another other stuff) are replaced. I will send you a report then.

On the other hand, if the leak gets much worst, then the 30K service may occur earlier...

Thanks again for your advise.

Bill