C5CORVETTE1

Hi guys, I did a search and Im still not sure. I have a 97 a4 c5 vette with 28k miles. The oil pressure is only at 30 psi on cold start up then it drops to 13-18 psi after warm up at idle. Should I be concerned about this and has anyone else had this low of oil pressure? Thanks for any help. James.

Mike94ZLT1

Yes. I would be concerned. 97 and 98 LS1's had issues with the pressure relief valve sticking open and causing low pressure. You should have 40-55 at cold idle, and 30-40 at hot idle. That is the norm, however the service manual states that you need 7psi at idle. Does the pressure come up with RPMs?

jch1

where is the pressure release valve, and how do you tell if its sticking open

vsocks1

I believe the pressure release is in the oil pump.

C5CORVETTE1

yes the pressure rises but not very fast. Under normal driving my oil pressure is only around 24psi. How would I fix the pressure relief valve ? Is it something that can be done while in the car or does the motor have to be pulled? Thanks again for all the help.

Mike94ZLT1

It can be done with the engine in the car, but you have to replace the oil pump. 24 while driving is low, although 10 psi per 1000 rpm is considered safe. However, I would fix it as soon as possible, as it may fail completely and then you have a big problem. How mechanically inclined are you?

Camjamsdad

I'd check the pressure with an external pressure gauge to make sure you really have low pressure. If those numbers are real I would be concerned. There are other things that can cause low pressure and none are good. I just saw you had 28,000 miles. That should rule out spun/worn bearings and stuff.

Different brands of oil filters can cause some variance but not as low as you are showing.

I hit 99,000 miles today and changed my oil. I have 44 at idle and 55-60 at speed.

vsocks1

I have a QTP high performance oil pump that sells for $180 that I can sell you for $90 shipped.

C5CORVETTE1

Im pretty mechanically inclined and have a hoist. Whats all involved in doing the job or do you have a link that shows how to do it?

Vsocks, I will let you know on the pump. Is that pump commonly used when changing out the stock oil pump? Is it a upgraded pump? Thanks again to all that has responded.

Mike94ZLT1

I think a stock LS6 pump will fit the bill just fine, last I checked you can pick one up from Gene for about $60, but $90 for a QTP pump is a GREAT deal, I would jump on that. www.LS1howto.com will go over the oil pump replacement, basically you have to do everything you would normally do to change a cam, except the whole camshaft part. At this point you would literally be a few bolts away from a new cam, so.... You know where I'm going with this

http://www.ls1howto.com/index.php?article=1

Ignore the part about the heads, unless you want to change them too.

C5CORVETTE1

Mike, Thanks for all your help. I just just changed the oil and it was pretty dark and the oil pressure went right up. Its holding 32lbs at 600rpms & 33lbs at 700rpms. temp is 165-170*. The oil filter was a techron brand, which I think is a wal-mart brand, and I switched it over to a delco brand. Hope this solves the problem. I will keep you all posted after I take her for a drive and get her up to temp. Thanks again to everyone's input.

vsocks1

Yes the QTP is an upgraded higher volume/pressure pump. Let me know as I will be putting it in the for sale section real soon!

C5CORVETTE1

I will let you know. Thanks.