Oil pressure

The Beav · July 1, 2003

What's the 'normal' operating oil pressure on a 99 Blazer? I'm running about 40 under most conditions and this seems low as my 01 Z71 runs about 65 under the same conditions.

Rotorwrench · July 1, 2003

The old rule I allways heard was 10 PSI for every 1000 RPMs. How many miles do you have on the 99?

The Beav · July 1, 2003

@ 71,500 and even at 75 mph I'm running @ 40psi

Rotorwrench · July 1, 2003

If you're not getting the 10 PSI per 1000 RPM you could have one of several problems. Weak oil pump, oil pump pickup screen blocked, oil pressure sending unit bad, or something internal that is loosing the pressure. The easiest and cheapest thing to try is the sending unit. Unless it's really bugging you, I wouldn't worry about trying to fix anything inside the engine unless you loose more pressure.

bigtruck21 · July 3, 2003

@ 71,500 and even at 75 mph I'm running @ 40psi

You are at or under 4,000rpms at 75 mph right? If so you are fine. I'd assume you are around 2250 rpms for that speed. Two other s-10 blazers a 99 and a 00 have around the same pressure. They have boosted it on the bigger engines, but don't need to on the smaller ones because they aren't as much of a workhorse.