View Full Version : Yanmar 6LY 2AP 440HP High Oil Pressure

Al Ebstein
12-20-2007, 01:36 PM
"Port engine runs at 75psi while starboard runs at 115-125psi at WOT. It is either real or I have a sensor or gage problem on starboard engine. This engine was at 75psi before an oil change. Went to 120psi right after the oil change. Port engine at75psi before and after the oil change. Both engines run well, no temp problems no smoke they sound the same too.

Has anyone ever run into this before? and if so what was found t be the problem."

12-21-2007, 08:22 PM
take the senders and switch them from one engine to the other and see what it does. I have found that the senders that Yanmar use have been not all that accurate. Try that and see what happens.
Guages are usually good. Then not with out faults either. In most cases it is the senders.

12-21-2007, 10:50 PM
"first, verify that the pressure is real. switch sensors as advised, or use a mechanical O.P. guage. (my preference) most of the larger yanmars have an oil pressure regulator. it may be sticking. normally it would be located in the bottom of the oil cooler. large plug with spring and plunger above. definately get a service manual if you are going to do any maintainance or repairs yourself. the yanmar factory manuals are excellent and very easy to understand."