Oil in Bilge Again!

M

Mister Crabs

New Member
Mar 22, 2009
25
Round Rock, Texas
Boat Info
2007 250 SLX
Engines
6.2 MPI
Ok, here's the deal.... My boat has been to the dealer twice for the same problem. Oil is leaking into the bilge while underway. I can't find the source of the leak, and the dealer can't find the source either! The dealer pulled the engine and replaced the timing chain cover and gasket, and after one time on the water for about 1 hour, the leak is back! I'm beginning to wonder if my fuel tank may have a slow leak, but I am not smelling gas. It does not appear to be gear oil. It looks like motor oil in the water in the bilge. I thought it might be coming from the rear seal, but dealer said they could not see the leak there. Anyone have a similar problem? I guess it's back to the dealer! Mercruiser was nice to cover the issue under warranty!:huh:
 
Mister Crabs said:
Ok, here's the deal.... My boat has been to the dealer twice for the same problem. Oil is leaking into the bilge while underway. I can't find the source of the leak, and the dealer can't find the source either! The dealer pulled the engine and replaced the timing chain cover and gasket, and after one time on the water for about 1 hour, the leak is back! I'm beginning to wonder if my fuel tank may have a slow leak, but I am not smelling gas. It does not appear to be gear oil. It looks like motor oil in the water in the bilge. I thought it might be coming from the rear seal, but dealer said they could not see the leak there. Anyone have a similar problem? I guess it's back to the dealer! Mercruiser was nice to cover the issue under warranty!:huh:
Click to expand...

Oil pan gasget?? :huh:
 
Oil sender leaking? Oil filter block adapter/lines leaking? This is extremely hard to diagnose over a forum - we could probably have numerous posts of guesses. Did your mechanic replace the timing cover because that's where the leak was coming from, or were they just guessing?

The first thing to do is to de-grease the ENTIRE engine block and bilge REALLY well (Todd, if you're reading this, can you show him a picture of what I mean?:smt001). Then you'll have to check the front/sides/back of the engine every so often to try and track down where the leak is coming from. You can secure paper towels in certain areas to help. Buy a decent sized mirror-on-a-stick - that and a good flashlight will be your best friends.

Are you positive that it is engine oil from the engine? The drive trim pump can use engine oil, too. Check your levels to see which is low (if it's leaking enough).
 
If they pulled the engine to fix the leak they should have been able to tell then that the leak was at the timing chain cover. I had to have my engine pulled a few years ago for the exact same problem. Make sure they really put a new cover on since they are not supposed to be re-used. The new ones are composite as opposed to the steel ones they used to use. I wouldn't be surprised to see the leak in the exact same place again.

Dave
 
Here is a little tip for those hard to find leaks.

Do as Dennis says and get the motor realy clean.

Then sprinkle talcum powder all around the places where you think the leak may be.

There are not many places a SBC can leak oil. Valve covers, Distributor mounting gasket, pressure sender, oil pressure switch, crank shaft seal in timing cover, timing cover, rear crank seal, oil pan gasket, dip stick tube "O" ring, sump plug.

So, just spread the talc around all those places and take her for a run. The leak will discolour the talc. :thumbsup:
 
If the 6.2 oil filter has been relocated, you might also want to check the hoses connecting the filter mount to the original mounting point. We had a leak on one of those this spring.

Henry
 
Why didn't anywone suggest a UV dye? Most car dealerships will put in a UV dye and run it for a while then look at the engine with a UV light, any leak will fluoresce.
 
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