Oil Pressure Problems

By: Grid Michal

QuestionI changed the oil on my twin 454 Crusaders, and on my first trip out on the water, the oil pressure on both engines was only at 30 psi, when it normally is 45 psi. I used the same weight oil I always have, but I purchased the Penzoil brand this year. Is it at all possible that the oil could be the cause? I did change the oil filters and had a bit of an issue when the gasket on one of the filters didn’t seat properly and I had oil spraying out of the filter for a few minutes. I did correct that issue but am concerned about the oil pressure. I should add the boat is a 1982 35-foot Viking Convertible and the engines were new in 2004. Any thoughts?

AnswerMy thoughts are several, as both engines are involved.

First, you have nine seasons on the engines, or roughly 900 hours, which puts you two-thirds of the way into the lives of the engines. I’d expect to see a reduction in oil pressure readings, but not specifically 15 psi on both engines.

Are you certain about the viscosity? It should be 20W50 as a normal oil (vs. synthetic).

Did you run the engines long enough after changing the oil to let the viscosity build?

I keep coming back to a change in viscosity from previous seasons.


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