First I think I would change back to 5w-30 synthetic. Then here is the pressures right out of the manual for a 1997. Possibly they may be different for different years. maybe someone could chime in for your year. I also just needed to install a new oil pressure sensor from Autozone, it was a Brass Borg-Warner one and noticed my pressure were slightly different then when the original GM sensor was in.
6.0 psig at 1000 RPM
18.0 psig at 2000 RPM
24.0 psig at 4000 RPM
Even with my super high-mileage '99, the oil pressure in hot temps and with the engine hot, only got down to 19 psi. As stated, minimum is 6 psi. The dealer or mechanic can do a mechanical oil pressure test to verify. Your's getting down to 11-12, I'd be concerned. You might want to pull and replace the oil filter and cutting open the removed filter to check for metal bits trapped within. If you find none, that would obviously be a good thing and good for the peace of mind.
Sorry for not staying up with my own post. Can't tell you what brand the filter is, had it done at the local oil change place. It is Mobil One oil. The problem has occurred over a couple of oil changes. The first was done by a local guy who did some other work on the car. I am about due for another change. What filter would you suggest?
Thanks again guys, already did the sending unit replacement. Getting good pressure with rpm, 30's - 40's at normal driving speed. About how much to have someone replace the oil pump? ballpark,,,,
Chances are a new oil pump would give about the same pressures. With 88K miles, hot weather your idle pressure sound fine as long as it comes up to a higher value off idle. One way to get higher oil pressure is to drop in a new LS2 or LS7! That would be my choice over just and oil pump!!
That amount of oil pressure is normal and should be no problem at all.Electronic oil pressure gauges arent all that accurate.LOL, if you are planning on a replacement,quit worrying and drive her til she blows!
mine c5z is a 2001 and the normal was around 35psi at idle and it has
80k on it. Just did a cam and mellon oil pump now its more around 45-50 at idle. Sounds a little low for me but thats just my .02 cents.