View Full Version : Major Oil Leak

04-02-2007, 04:23 PM
"This major oil leak has happened twice with my Yanmar 4JH-HTE (6500 hrs) and I'm trying to determine the source of the problem. We purchased the boat in October and motored many hours before this problem started.

In November the boatyard changed the oil, including a new Yanmar oil filter. Following that service, within minutes of running the engine, the oil was all over the engine compartment, with none left in the engine. The filter was still attached, and nothing looked wrong, but the problem was identified as a defective Yanmar filter, specifically with the 0-ring. The filter was replaced, and we have had no additional problems until now. Obviously, during the winter months very few hours were put on the engine. However, we had taken several weekend trips without a problem.

The boat is back at the boatyard for the pre-season maintenance, and while running the engine at the dock, the same thing happened again. I am really concerned that the problem needs to be appropriately identified so that permanent engine problems aren't created.

Has anyone experienced this problem or have some suggestions?"

05-01-2007, 09:05 AM
have the oil filter bypass valve checked. could be building exess pressure in filter.