I've had my 99' for a week now and i noticed today that the oil pressure sits at 20psi during idle and was wondering if this is normal?

 

Not uncommon and should be safe. IIRC, GM calls for 8psi minimum at idle. The old rule of thumb is 10psi for each 1,000 rpm.

 

thanks, thats a relief. the reason i was worried was because i did some work on a 02' sonoma and noticed that the pressure sat at 40psi during idle.could this show that my oil pump is starting to fail?

 

Not necessarily. Factory oil gauges vary in accuracy so the way to be certain is to attach a manual gauge with a t-fitting at the sending unit port and compare both gauge readings. If there is a large difference in the two, you will most likely decide to replace the oil pressure sensor or just let things be.

 

I could be signs that your oil pump is getting weak, or possible some sort of small obstruction on your oil pick up screen. How much mileage does it have? I agree with Rriddle, you should be fine as long as it doesn't drop down below 10psi. I would try changing the oil, dump a few cheap quarts of oil through it and let them drain out then close up the drain plug and do your normal oil change then see what your pressure is.. if it is stil labout the same maybe go to a 10w30 or 10w40 and that should help alot.

 

I own three chevy trucks, 02 blazer, 99 sub, 93 1500. with 10w30 they all idle at 20-25 psi when fully hot, that is after about 30 mins driving. Remember, when warming up, just because temp gauge says full temp the oil temp is lagging behind a bit. When cold they idle about 40psi. i bought the blazer new and it has done that forever. it may have lost about 5 psi but it has 180K miles on it.

 

the blazer just hit 150k and i dont think the oil pressure ever goes much over 40psi even at WOT. also, the valvetrain clacks really bad in the morning sometimes.

 

Yah each engine has a little different pressure and even among the same engines you will see some difference due to the cheap gauges they use and the boat of other variables like oil weight, type, use of oil stablizers, and even how full it is. Ive noticed on mine at the bottom of the full hash marks is about 5psi lower pressure than the top of the hash marks. My dads 4.8 is like 45 cold and 20 hot where my 4.3 is 65 cold and 25 hot. If you were at like 5 psi you would probably start noticing some noise since the oil wouldnt probably make it all around the engine too well.

 

From the sounds of it, you have nothing to worry about jcon82.

 

Thanks for the help, I'll just put some 10-30 in it when i change the oil and let it be.