So my E32 750il has developed a fuel leak. All the gas leaked out into my drive way over the course of about 4 days:shifty. So I get the gas can put three gallons in to drive it to my mechanic. Wont start just cranks. So I do the standard fluid check and all that good stuff, The oil was milky:mad so of course I figure that I have a blown head gasket. However, the last time I drove it it ran fine. No smoke/steam and no knocking of any kind. I am also quite certain that none else drove it, What could it be? Any idea?


Thank you guys so much!

When was the last time you drove it?

It's possible that just before you shut it down the last time you drove it, the head gasket blew without you knowing it. Now, you've got a major problem on your hands.....dig deep.

Sorry.

jake

you need to do a compression test and share the results.
i can give you a much better diagnosis then.

On thursday it is being taken down for a compression test.

Any one?

That is not enough info. Milky can also be an oil from a car which is only used for short distances and the system never gets really to operating temperature.
What do you mean by milky anyway? White? Chocolate cream?

Have you checked the cause of the sudden fuel drain? Any rodents there which chewed on the hoses? In some areas martens and other rodents like to chew ignition wires and cables. Did you check that?
Do you get sparks? Do you get voltage on both ignition coils? Do you have fuel coming out from the fuel hoses from both fuel pumps? Is the fuel pump pressure high enough that the sparts come from the ignition?
What is the battery voltage and the cranking voltage?
Many questions unanswered. Check all these things step by step, tell us the result and then we will guide you.

The oil is like this brown/cream colored. Very similar to coffee with milk.
I really hope it isn't the head gasket, that would suck.

It really does sound like a blown head gasket. Been there but with my mustan
g. (built a motor without mls gaskets, and they blew under power)

Do a leakdown test, you will be able to pinpoint *exactly* where/if you are losing compression.

Hmm, what exactly is a leak down test?

A leak down or "cylinder leakage" test is similar to a compression test in that it tells you how well your engine’s cylinders are sealing. But instead of measuring pressure, it measures pressure loss.

A leak down test requires the removal of all the spark plugs. The crankshaft is then turned so that each piston is at top dead center (both valves closed) when each cylinder is tested. Most people start with cylinder number one and follow the engine’s firing order.

A threaded coupling attached to a leakage gauge is screwed into a spark plug hole. Compressed air (80 to 90 psi) is then fed into the cylinder.

An engine in great condition should generally show only 5 to 10% leakage. An engine that’s still in pretty good condition may show up to 20% leakage. But more than 30% leakage indicates trouble.

The neat thing about a leakage test (as opposed to a compression test) is that it’s faster and easier to figure out where the pressure is going. If you hear air coming out of the tailpipe, it indicates a leaky exhaust valve. Air coming out of the throttle body or carburetor would point to a leaky intake valve. Air coming out of the breather vent or PCV valve fitting would tell you the rings and/or cylinders are worn.

A leakage test can also be used in conjunction with a compression test to diagnose other kinds of problems.

A cylinder that has poor compression, but minimal leakage, usually has a valvetrain problem such as a worn cam lobe, broken valve spring, collapsed lifter, bent push rod, etc.

If all the cylinders have low compression, but show minimal leakage, the most likely cause is incorrect valve timing. The timing belt or chain may be off a notch or two.

If compression is good and leakage is minimal, but a cylinder is misfiring or shows up weak in a power balance test, it indicates a fuel delivery (bad injector) or ignition problem (fouled spark plug or bad plug wire).


http://en.wikipedia.org/wiki/Leak-down_tester

The fuel leak turned out to be from a fuel pump. One the mechanic gets it running he is gonna test the engine.