Higher than usual oil pressure

[Begester]

Hello Fellow boaters,

I'm getting ready for summer (finally decent enough weather in the Pacific NW) and took my 1989 SeaRay 220DA w/ 5.7l out for a test run last night. I did a minor tune up over the winter, which included changing the oil/filter as well as swapping the radiator cap and noticed that my oil pressure is up by about 15 psi. I am wondering if either the fresh oil w/ a different viscosity or the new radiator cap possibly creating higher pressure throughout my engine, could have anything to do with this. Has anyone seen similar on their boats?

My boat has 1000 hours and ran beautifully, aside from this, which I only recognized because I was keeping an eye on the gauge. I felt no power loss or lag at all. At idle, the pressure is right at 40 psi (gauge is right in the center.) Last year, at idle, the gauge was slightly lower and the pressure was dead center when I was at about 2700 rpm. I am fairly certain that higher oil pressure is better than lower oil pressure, but I'd rather find out and fix something now as opposed to having a problem when I'm out on the water.

Admittedly, I'm no expert with regard to the inner workings of internal combustion engines, so apologies if this is a dumb question.

Thanks for the help!

 

[boat1010]

Re: Higher than usual oil pressure

The radiator cap makes no difference. The oil viscosity and temp. do make a difference. So with that said if you changed oil viscosity to a thicker weight that will bring up the pressure. Not knowing if the motor was up to temp when you were checking the pressure but it doesn't seem out of context to have a little higher pressure after changing oil. I'm not sure what viscosity your motor calls for but would make sure you run the right viscosity. Other than that I think it is just fine. About the only things that can change the pressure are viscosity, temperature, and the oil pump. Some time the sending units go bad too. So if you have the same viscosity oil and it is still to high when you have the motor up to temp, I would just look at changing the sending unit. They are pretty cheep. Hope that helped.

 

[nola mike]

Re: Higher than usual oil pressure

fwiw, mine did the same thing when i changed the oil for the first time. i used the recommended straight weight sae 40--i suspect the PO had a multigrade in it.

 

[Begester]

Re: Higher than usual oil pressure

Thanks for the help. I believe it was a slightly thicker viscosity so that's probably it.
I also used Valvoline instead of Mercruiser oil so that could have a slight factor as well.

Thanks again!