Oil leak

[Jim c]

Hi I just install a early modal A4 supposedly remanufactured ,getting ready to start it for the first-time I reached under the engine and found 1/2 inch of fresh oil in the bilge !! Now can anybody tell me (not being a Mechanic ) the easiest way to detect where the the leak is without the engine runing ?which are the most likely place to look first before pulling the engine out . Thank you Jim

[jcwright]

Hello Jim.

Here is a thread that includes a very helpful summary by Jeff on likely sources of oil leaks. See especially post #3:

https://www.moyermarineforum.com/forums/showthread.php?t=10075

That said, I see that you just installed the engine. If the engine was tilted forward during installation, oil may have leaked past the 'slinger seal'; this would not necessarily indicate anything is wrong with your rebuild. Here is an MMI FAQ about this:

"There are only three sources for a continuing oil leak appearing below the flywheel housing: (listed somewhat in order of likelihood)

1) Overfilling the crank case. There is no conventional seal in front of the crankshaft, and if the crankcase is overfilled by much more than a quart or so, some oil can splash out of the front of the engine, just behind the flywheel, especially when sailing in choppy water.

2) A leaky gasket between the flywheel housing and the front of the block. Such a leak would be very unusual except possibly immediately after an overhaul.

3) Clogged drain holes in the “slinger seal” in front of the crankshaft.

The slinger seal consists of a collar machined around the front of the crankshaft where it extends out through the flywheel housing, just behind the flywheel. The outside edge of this collar is sharpened to a dull edge which lines up with the inside diameter of the hole in the flywheel housing. When oil tries to leave the crankcase, it encounters the crankcase side of this collar, and gets “slung” outward (hence the the name “slinger seal”) into a groove cut into the inside diameter of the hole in the flywheel housing.

There are small drain holes (approximately 5) in the bottom of the groove around the inside of the hole in the flywheel housing, which allows the oil to flow back into the crankcase after it is flung outward into the groove by the edge of the sharpened collar on the crankshaft.

Every now and then, those holes get clogged with crud and oil cannot flow back into the crankcase as fast as it is being flung out by the slinging collar. – Updated: November 4, 2003"

[Jim c]

Allright Thank you JC great place to start,Right off the bat i can eliminate a few thing from the list ,no oil in the engine when install ,only about 3 1/2 quart in engine ,engine never ran .Now the valve lifter cover a good place to look,Thank again JC

[jcwright]

Hello again Jim.

Thanks for the update. My valve cover did leak a bit after a rebuild, partly because I did not use any sealant. However 1/2" of oil in the bilge would be a lot to get past the galley plate even if the engine were running.

Let us know what you discover.

Best regards,

Jack

[Dave Neptune]

Lots of oil

Jim, if you just installed, how long did it take to get that 1/2" of oil? Have you run the engine?

One possibility if the engine has not been run is that the oil was dumped out of the engine while installing through the front bearing as there IS NO SEAL there.

Did the oil level on the dipstick drop or did it possibly rise? Make sure there is no water under the oil in the pan.

Dave Neptune