91_Formula

iTrader: (1)

I recently bought a 1991 Formula with an L98 and it has aprox 47,000 miles on it. When I got it the oil pressure was higher than I expected.

Cold idle (~800 rpm) is approx 60 psi
Warm idle (~600 rpm) is 30 psi

Cold 2000 rpm 60+ psi
Operating temp 2000 rpm 50+ psi

All of these readings are off of the stock gauges. I thought the previous owner may have put in thicker than recommended oil. So I changed it out and replaced it with 5w30 Mobil 1 synthetic. The pressure is the same. To the best of my knowledge the engine is stock and never been worked on.

Are these pressures normal? (not that I am complaining at all.)

Thanks

five7kid

iTrader: (14)

Maybe slightly higher.

Your gage may be reading higher than actual. That's pretty common. Hook up a mechanical gage and compare.

91_Formula

iTrader: (1)

Thanks, I'll give that a try. Any idea as to what readings I should see?

xlwhellraiser

iTrader: (1)

I don't think you need to worry about anything. Actually your car holds great pressure. Now, low pressure is something you need to be worried about.

I drove vettes with L98's that had pressure go over 80. Nothing wrong with that.

The way I look at it is, look at the guage. Look where it says 60. Is that area red? Red like 260degrees is, or like below 8volts charge is, or 6K red line?? Nope, so nothing is telling you that you should worry about it.

Mine runs like you are describing, brand new motor with 20K on it with 5W30. I am very pleased, one of the very few reasons a 305 is still hanging there.