Anyone have HOT oil pressure observations?

So, I took the boat to the lake yesterday to check everything out, before we leave on Saturday, and was horsing the boat up the hill.

Not a huge grade, probably 4-5% for ~2-3 miles. 45-55mph, 3rd locked out and turning ~2400 rpm.
Temps:
Ambient 92F
Water 200-210
Trans 175-180
Pyro 800-1000
Oil Pressure (at~2400rpm) >60psi

Now the biggie: At idle after the hill, the oil pressure was ~12psi. Once I got back into the city and driving around, oil pressure cam back up to it's normal hot ~16-18psi. i.e. the oil cooled down.

I am running Valvoline 15W40 w/ a stratopore filter and was changed about 1k ago.

I recall reading in the DC manual that anything over 10psi at idle and over 30 psi at 2500rpm is acceptable.

I am assuming this is normal oi thinning due to temperature.

Anyone else see this?

TIA

Tony

 

I'm using a Autometer Phantom mechanical gauge and even after a fairly hard run I see 20-22 psi. The truck has 14K on it.

Cold (45-50F), I see 90 psi at cruise (1000 rpm), dropping to 65-70 psi at operating temperature at cruise.

Dale