I've noticed recently that my oil pressure at idle has dropped of somewhat. It's been unusually hot the last few days and today the needle dropped into the red.

It's fine over 1200 rpm and displays what I am used to seeing at various rpm except idle, so I don't think it's an instrumentation issue.

Is my oil pump failing or do I need to step up to a 20/50 grade oil for the summer months. I'm currently running Royal Purple 10/40.

Thanks,
Jon

 

I would get a cheap pressure guage to verrify the oil pressure. If the two guages agree then step up the oil thickness. Pumps rarely go bad and its usually bearing clearance that causes pressure drop.

 

My old 305 Z with 150k miles runs well but the oil pressure
is usually around 30-40 lbs no matter what.
Same deal with my old GTO 400 with 175k !!!!!!!!

As long as you have oil pressure your pump is good.
High mileage motors are worn with big tolerances so
therefore low oil pressure. If the motor ain't knockin'
and your not doing 6500 rpm shiftin' your good to go!

My suggestion.............Use straight weight 30 or 40 weight oil.
Don't waste your money on that fancy stuff !

 

Verify the reading first with a mechanical guage, as posted above. The factory sender and/or guage are known problems with these cars. If it really is low, try a little heavier oil (try a 15-40 if you're using a 10-30 now) and see if that helps.

 

My '91 has 121k on it and in the past year my oil pressure gauge was registering almost redline in the summer (idle, little improvement on acceleration). Come to find out it was the gauge which got replaced this spring...glad to see that this isn't too uncommon...

 

What Air Adam said. Also, a few additional points.
Oil pump is a gear type pump. As it wears, it will not maintain pressure as well at lower speeds.
If test proves pressure to be low, carefully inspect oil after draining for any trace of metal.
Stick with a good quality multi viscosity oil. Single viscosity oils thin with heat and will cause a drop in pressure with high temps.

 

Thanks for all the replies. The engine and the pump are relatively new. I haven't been able to mechanically test the oil pressure and compare with the dash gauge yet. I'm hoping to find time to drain and inspect the oil this afternoon.

Thanks again,
Jon