I have a 671 marine diesel that has always been dependable. I had a business partner that was handling the maintenance and, well was not doing it well. Enough said I am now learning oodles about the intricate maint of a 671.
I had a late fall contract where I was towing a sidescan for about 6-7hrs a day at an average of 4 knots. On the return voyage (from the survey site at approx 8 knots) she would smoke like hell. I understand that the 671 does not like low rpms especially for extended periods. What I noticed was an absence of wet-stacking and the trademark spots that are usually spattered around the deck. This condition happened a couple of years before when a contract required me to operate at idle for nearly 24 hrs straight.
What I did notice, in addition to the smoke, (white) was black goo oozing out of the exhaust at a clamp joint. Of course it was running on to the fixed manifold and burning off. Additionally I have noticed oil stains around the air box covers.
My questions are 1. is this normal because of the low RPMs and the result of a failed seal at the exhaust joint; 2. Is this the result of a potentially larger problem brewing...or already brewed.
I have included a couple of photos to highlight where the goo was oozing from, a photo of the engine and a photo of the blower as I was told the blower gasket could be blown which would cause the air-box leak. On the blower photo you can see a oil stain in the lower left hand corner of the photo. The air-box photo is not that great but you can see some staining.
Any experience or insight would be greatly appreciated
671 Detroit Oil Leaks
Re: 671 Detroit Oil Leaks
