View Full Version : 2qm15 low oil pressure when warm

Lloyd Heim
09-15-2008, 07:40 PM
After running my 2qm15 for an hour the oil pressure is 8# at 800 rpm and 16# at 2000 rpm. When engine is cold it is 43# at 800 rpm and 48# at 2000 rpm. The engine is not running hot. I'm using Shell Rotella T 15W-40 oil.
Checked the pressure with a mechanical gauge in parallel with the electrical gauge and they read within 1 # of each other through the entire range. The oil is fine.

The engine is a 1979 and never did have great pressure even when it was new but it was over twice what it is now when warm. I did pull the oil pump about twelve years ago and they said it checked out ok. I also put a new spring and ball assembly in the pressure regulator at that time also. Did not change the readings. The engine has about 900 hours on it. Never had a problem with smoke. The pressure when warm goes down a little each year.

09-21-2008, 02:25 PM
"Max oil press on this engine is 50 #
Try using 15W40 in Esso or a good diesel lube oil other than Shell. The regulator also has shims, check what the Yanmar workshop manual states for adjustments."