greenc5

Went for a drive today, about 90 degrees in Columbus. Noticed at an idle the oil pressure dropped to 14. oil temp and coolant temp both about 225. Oil level is full. 87,000 miles.

Had this problem last summer when it actually dropped as low as 12. changed to 10w30. Looks like that didn't help much.

Any suggestions would be greatly appreciated.

02Z06clark

Oil pump possibly ?

lucky131969

greenc5

That's what I'm afraid of, hoping someone would have some other ideas before I go there.

glkfam

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

greenc5

It might just be normal, i get good pressure at higher rpm's. mine is a 2000 by the way. It's due for a change, so I probably will go back to the 5w30 (mobile one). Thanks for the response.

dgrant3830

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.

greenc5

Appreciate the answers. Anyone have an idea of what it would cost to replace the oil pump?

ALLEGRO

Which filter brand do you have on her? could be a restrictive filter.

greenc5

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?

jrprich

Couldn't it be a bad oil pressure sending unit?
These are known to fail on C5s. Usually they report higher than normal pressure, but perhaps your is doing the opposite.

slothy

USING 10-30 IN MY CAR, so its not the oil

any ticking noises?

i would have a mechanic put a mechanical oil pressure tested on it and see if the sensor is reading bad or you have another issues like failing oil pump.

greenc5

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,,,,

Eric D

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!!

greenc5

Eric D,,,

I like the way you talk, both the "sounds fine" and the LS2/LS7...... That's a long range plan for now.

Thanks

buoniconti81

Gm stated that there manual said that anything above 9psi and below 65 psi... Its a funny thing? I had the same problem, it was my oil filter clogged.....

buoniconti81

Good time to run some sea foam through the car, and change that oil/filter...

Eric D

Clogged with what?

rebelheart

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!

red2001z06

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.