oil pressure question...

[hotmerc]

my 5.0 merc is a 1987 vintage. at first start up the oil pressure runs about 50 psi. after warmup it seems to drop. at a cruise it will run between 25 - 35 psi and i'm running sae 30 oil. i was told that low oil pressure in an older motor is common, being that the oil will thin out, as long as the gauge doesn't read 0! is there any truth to this?

 

[snapperbait]

Re: oil pressure question...

As long as you have at least 10psi for every 1000rpms, your ok....<br /><br />example: running 3500rpm, the engine needs a minimum of 35psi oil pressure..

 

[rodbolt]

Re: oil pressure question...

Hello<br /> that oil pressure sounds ok to me. I think the oil pump pressre relief is set about 35-40 psi.<br /> I think the spec is about 15 psi at 2000 rpm minimum. oil pressure gauges are like temp gauges. I think they are overated. buy the low pressure/ high temp audible alarm kit. <br /> good luck and happy boating