Cold Engine, high oil pressure

[diveman05]

Good morning everyone, we recently purchased an 89 four winns 205 sundowner with a 5.0 ho omc, model #502APRMED. Only put about 3-4 hours of actual engine run time on it since we've gotten it, we like to launch go to our spot and start relaxing and drinking :joyous:

Anyway the temp gauge never reads over 100, except when the impeller broke and it got up to 160, this was kind of my test if the temp gauge actually worked.

Oil pressure seems high to me, always near 80psi, probably closer to 60 when idle and slow and 70 when on plane. I looked in the manual and couldn't find the recc. oil pressure so maybe its fine.

My thought is thermostat stuck open, keeping engine cold thus keeping the oil thick and pressure up. (marina said to and used SAE30 on it)

Replacing the thermostat according to the book looks pretty easy, they say to remove the hoses take out the two bolts, pull apart, clean, and replace rubber o ring, thermostat, and the gasket.

Am i missing anything here, any other points of view that i may be blindly overlooking?

Thanks!

 

[Boomyal]

Re: Cold Engine, high oil pressure

All makes sense. Cold engine, thick oil= high oil pressure. Is that 5.0 a ford or a chevy motor? My 5.0 Ford does run up around 60 lbs.

If it does not get past 100?, I doubt it even has a thermostat in it although some thermostats are fail open. You will get excessive cylinder wear running anywhere near that cold. If you never run in salt water, I would run a 180? stat! I don't care what the manual or other posters say. 140-160? is still too cold for ideal. Factories used cooler stats because they did not know where the boat would be used. Salt tends to plate out in the engine when you run it in the, otherwise, ideal range of 180-190?.

 

[diveman05]

Re: Cold Engine, high oil pressure

All makes sense. Cold engine, thick oil= high oil pressure. Is that 5.0 a ford or a chevy motor? My 5.0 Ford does run up around 60 lbs.

If it does not get past 100?, I doubt it even has a thermostat in it although some thermostats are fail open. You will get excessive cylinder wear running anywhere near that cold. If you never run in salt water, I would run a 180? stat! I don't care what the manual or other posters say. 140-160? is still too cold for ideal. Factories used cooler stats because they did not know where the boat would be used. Salt tends to plate out in the engine when you run it in the, otherwise, ideal range of 180-190?.

Boomyal, thanks for the reply, its the Ford motor. I was thinking the same thing about no thermostat as it never warms up. Oil pressure i think i'll get the stat changed and then see if it goes down some, if not maybe do a gauge and sender test to make sure both of those are running properly and take it from there.