omc 5.8L 1989 oil pressure

[a1a2a3a4]

I have an omc 5.8L 1989. Recently I had my intake cooling water blocked and engine reached 230 (normal running temperature 140). I removed the blockage and replaced the impeller. Temperature is back to normal.
I noticed that the engine oil pressure starts at 50psi (cold idling), then keeps it the same on high revs (about 3000-4000) but if I turn it back to idle after 20minutes drive on high revs the oil pressure will get down to 18PSI or even 12 psi. There is no pressure drop on high revs but on idling hot it seems to me to low. IS this normal????

 

[Bondo]

Re: omc 5.8L 1989 oil pressure

IS this normal????

Yes...

 

[dakine]

Re: omc 5.8L 1989 oil pressure

My 351 w has about 30 psi hot.
12 psi at idle is below spec.
What weight oil are you using?

 

[Aloysius]

Re: omc 5.8L 1989 oil pressure

Sounds fine to me, especially if it has always done that. You worry when oil pressure CHANGES.

 

[Howard Sterndrive]

Re: omc 5.8L 1989 oil pressure

as much as I hate to ask this:
what weight of oil are you running?

 

[a1a2a3a4]

Re: omc 5.8L 1989 oil pressure

Hi

I have owned this boat for 3 seasons. The last two seasons I used straight 30W oil. Before I am not sure what kind of oil was used but I believe they used 15W-40W.

Are there any test or symptoms that I should notice to prevent any damage??

Hansel

 

[Howard Sterndrive]

Re: omc 5.8L 1989 oil pressure

check pressure with a buordon tube gauge to verify accuracy of sender.

could run 40wt
try a different brand of oil filter

otherwise, wouldn't worry about it too much

 

[a1a2a3a4]

Re: omc 5.8L 1989 oil pressure

ok thanks. If some one else have any other idea`s or opinion please let me know.

 

[dakine]

Re: omc 5.8L 1989 oil pressure

It will be fine....until it isn't.
The old rule of thumb is ten psi of oil pressure for every 1000 rpms.
While yours is lower then I like..... the motor may run like this forever.
If there is a problem you will soon notice a rod sticking through the side of your block.