Hello all,
I have a 1988 740GL with a B230F. It is leaking oil, perhaps as much as 1/2 litre every couple of weeks. I cant find the leak. I am guessing its coming from the back of the engine somewhere, so it isnt obvious. I was told by someone that it might be a cam seal on the back of the head. When I looked I didnt seem to have a cam seal, the distributer was there instead. Any clue?

Yes there is a rear cam seal. It is really part of the distributor. Usually does not leak the amount you mention. If that is the source you will be able to feel the oil on the back of the engine as it runs down.
Before doing anything you must identify the source of the leak.
How do you know it is leaking? It could be burning, how many miles do drive in the 2 weeks?
Do you see oil on the ground when parked?
Have you looked carefully at the bottom of the engine for possible sources?
Sometimes it is necessary to clean the engine, drive it then check for the appearance of fresh oil.
It is very important to check your crankcase ventilation system, if clogged, excess crankcase pressure will force oil out through the seals. This is well covered in the FAQ section.

Possible leak areas:
Distributor
Valve cover gasket
Front seals (3 of them)
Rear main seal
Oil pan gasket
Oil drain plug

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David Hunter

Thanks for the help.

>How do you know it is leaking? Do you see oil on the ground when parked?
There is oil all over the ground under the car.

>It is very important to check your crankcase ventilation system, if clogged, >excess crankcase pressure will force oil out through the seals.
The PCV was cleaned when I first noticed the leak. Just finding where the leak is has been my problem.

There is no PVC valve so I suppose you mean the flame trap which does clog up. When checking the flame trap it is important to check it's vacume hose and brass nipple where it connects to the manifold, both will clog.

If the oil is dripping on the ground and you cannot see the source(s)from the top then you must go under and look around. If the leak is that bad you should be able to see where it is coming from.

--
David Hunter

Speaking from experience, those rear main seals will leak like that, but yours is likely a combination of bad seals that contribute to the overall oil loss. The best thing to do is steam clean the engine (or clean as much of the oil as possible) and drive it for a bit. I've heard of a flourescent additive that will glow under black light, telling you exactly where the fresh oil is coming from, but not sure if that's only available to mechanics.

The MOST important thing to consider if you're not doing the work yourself is to SHOP AROUND!! A few years ago (before I came across the workshop space that i have now) I tried to get my oil leaks on an 89 744GL solved, but the dealer wanted $2800! Instead, I took it to an indie guy who solved all the leaks for about $800 INcluding the RMS.

Cheers!