B.O. Oil Pressure

Oil cooler on my 7U sprung a leak. Decided to source a replacement rather than bypass it.

New oil & filters. Now on startup I get a little more than 20 pounds at idle, for about 10 minutes. Then the pressure drifts away. Thought it might be an obstruction at the pump pickup and checked that. New oil again, and as I was topping it up I noticed the oil on the dipstick seemed to be aerated.

I can’t see the forest for the trees. Any help identifying the cause?

Oil aeration is normally from pump cavitation. Worn pump or sucking air. Check at the connections where you changed the oil cooler. I have seen fuel systems that would not leak but suck air. Just as a test bypass the cooler and see if you get the same result. If you do you know it is not linked to the cooler and have to look at the motor side of things. A process of ruling things out. Good luck.

It never occurred to me that my D315 would suck (that's a joke son).

Going to follow your advice on the external plumbing before dropping the guard and pan. I should have been asking myself "what's been disturbed" first. Sucking air makes sense to me because of the time it takes for the pressure to start drifting away. Seems like if it were a pump problem there wouldn't ever be any pressure buildup, that cavitation would be immediate (but I often jump to the wrong conclusion). I guess agonizing over getting at the pump was throwing the blinders on.

Thank you.

If it wasn’t happening before you changed the cooler then the first place to start is where you have been working. Sometimes the problem may have been there but you only noticed because you have worked on the machine and have taken notice after fixing it. Keep us informed on what you find.

Chris.