View Full Version : Oil pressure droping

12-13-2008, 01:59 PM
I've got a 02 SS I bought with most of the mods already done it's got a forged 347 from tsp w 5.3 heads and it's got a ported LS6 oil pump. When I start the car it holds about 60 psi and it slowly drops and after about 15 mins its down to 0 psi. I figure it's pumping all the oil out of the pan and the oil's not making it back to the pan. Anyone ever seen this problem before?


12-13-2008, 03:01 PM
How many quarts did you put in it?

If it was at least four, you would have oil all over the place if it wasn't making it back to the pan.

Sounds like your oil pump install is bad (o ring).

It is a common error/problem.

12-13-2008, 03:05 PM
how much oil and what thickness. bad o-ring would bleed pressure from the beginning I would think. To me it sounds like wrong oil or a bad pump. As the oil warms and thins, the pressure drops.
What oil is in the car and how much?

12-13-2008, 03:41 PM
Dont drive it until you figure it out.

12-13-2008, 03:56 PM
10w40 mobil 1 5quarts

12-13-2008, 06:47 PM
i did run some mobil 1 15w50 for a while a friend talked me into that

12-13-2008, 07:18 PM
Hows the sending unit have u replace that? Oh dose it start to tick or knock when the oil pressure goes down?

12-13-2008, 09:00 PM
I haven't replaced the sending unit, it does start to knock a little when the oil pres gets to 0psi.

12-13-2008, 10:05 PM
I haven't replaced the sending unit, it does start to knock a little when the oil pres gets to 0psi.

Ohh... Dam Are you 100% sure there is nothing in the pan or the pickup is loose? What about the cam retainer I know if that is loose you will loose oil pressure. The only other thing is bearings. Oh what about the barbel by pass thing it may have come out.

12-13-2008, 11:11 PM
if its fine cold then drops off as the motor warms up i would suggest a pressure relief spring. i have had those exact same symptoms on another car i had. replace the pump.

12-14-2008, 04:20 AM
I had a Pump fail on me, tore the whole Engine up..:(

12-14-2008, 10:24 AM
I had a new pump from the dealership crap out after 1500 miles. The relief valve was stuck. I pulled the pump apart and the bottom of the relief valve had a bur around it. What a bunch of crap. Tear the front of the engine down and get a good look at things (cam retainer, pump, pump o ring, and the little freeze plug in the front) If nothing then I'd take the rear cover off and check the barbell out. Good luck with it.

12-14-2008, 02:23 PM
I agree with everyone else; don't drive or even start it anymore until the problem is fixed. It could be something as simple as the oil pump o-ring or something more serious. Either way, you will have to tear it down for an inspection.

12-14-2008, 02:30 PM
Bad o-ring wont have good pressure when cold....

I personally would be swapping to a new oil pump and start back up with 20w50 in it and see what happens. Check for bearing material in the oil when you drain it

12-14-2008, 02:34 PM
I vote bearing cam or main. I had a 5.3 do the same thing new pump fixed it for like 1 day right back to the same thing. My repair in the end pull the bastard out and install a 6.0

12-14-2008, 03:00 PM
I haven't replaced the sending unit, it does start to knock a little when the oil pres gets to 0psi.

I'd say its too late. You shouldn't let it run with 0 oil pressure. Thats got spun bearing written all over it. If it's started to knock, its only going to get worse and you have a bottom end knock now. I would have tore the front cover off and replaced the pump when you had the chance. Sounds like you will be doing a rebuild now.

12-14-2008, 05:39 PM
it doesnt knock at all when it has anything above 0 psi im gona order a oil pump after christmas and try that. what pump would yall recomend?

12-14-2008, 05:56 PM
I have a melling 295, no problems for me.

12-14-2008, 06:41 PM
295 here also