WI Tom

Ok so i just bought a '99 FRC and am having some oil pressure problems and I can't find anyone else that has had this issue.

When I first start the car up the gauge is reading around 40 psi at idle and 50+ on the gas which I believe is just fine. The problem is the longer i drive the lower the oil pressure reads. The day I bought it the pressure was fine when I first started it up and for the test drive, but on the hour and a half trip home it slowly went from the 40 psi at cold idle and 50+ at higher RPM to 13 while cruising and 7 at a red light which is very concerning.

From what 'I've read oil pressure problems can be from something as simple as an oil filter to clearances being high. So before I start blindly swapping parts if I could get any feedback from you guys it would be greatly appreciated.

I have an oil pump ordered for peace of mind just wondering if i can expect that to solve my problem. I'd really like to make it up to Brainard for the powercruise this weekend.

PREDATOR-Z

most likely it is not pump related, but bearing tolerances.

Justins00ss

iTrader: (18)

Could be pump related. The pressure relief valve in the pump could be starting to stick. I had that happen one day and it caused 0psi on start up. But I dont want to scare you. I just went through this with a 30k mile shortblock out of a corvette. I got the motor swapped into my camaro and got it running. Had about 45psi or so at start up and cold idle. Once I drove it a little bit and it warmed up it would drop down to 20psi UNDER A LOAD. After about 10 miles of driving it shot 2 connecting rods through the block. Not sure what caused it but the motor was dead quiet and then next thing I know it started clacking and BOOM!!! I would not drive it at all until you are sure your problem is fixed. Change out the oil and look for metal in it or in the filter.

KCS

iTrader: (20)

Need more details.

Rebuit engine? What oil? What pump? Verify oil pressure with a mechanical gauge yet?

thompson

iTrader: (4)

The only way to loose oil pressure is to have a lower volume (oil pump) or larger demand(leak). We rarely see any problems with pumps decreasing volume, in the time we have been building LS motors we have seen 1 plunger stick on the pump causing low oil pressure but have in many cases seen that there is significant bearing wear causing the oil pressure to drop as you get heat in the oil and begin to thin it out.
We wish you the best on the oil pump fixing the issue but if it does not work out give us a call and we can get you back on the road in no time and for less than you would think. Our ls short blocks start at $1619 and will resolve the oiling issues your are having if the pump does not.

Justins00ss

iTrader: (18)

Thats exactly what I was thinking. Most likely he has some worn rod/main bearings.

WI Tom

That's what I was afraid of. I left a message and texted the seller asking if he had any oil pressure problems and never got a response so I think I got screwed. I don't know if the engine has been rebuilt but I do know it is out of a 98 camaro. I havnt changed the oil yet because obviously I was going to do that with the pump. If it is tolerances could I go to a slightly thicker oil until I can afford a rebuild as a short term solution? I was thinking if it was tolerances and it was just from heating up it would eventually bottom out but it kept dropping the longer I drove, which lead me to think there was a bad seal somewhere. Pickup rube o-ring maybe?

Thanks for the responses. Hoping its not too major. Nothing worse than buying a car and it immediately turning into a paper weight.

thompson

iTrader: (4)

You can use a thicker oil but in my experience with bearing issues you typically experience bearing failure pretty quickly following oil pressure issues. Usually when you have a dramatic drop in oil pressure it is right on the edge of spinning a bearing. Let us know if we can help.

1-87 chevy

iTrader: (15)

sounds like a spun cam bearing

td1168

iTrader: (2)

Are you hearing any irregular engine noises? At 7 pounds you should be hearing something. First thing you should do is verify the pressure with a mechanical gauge and go from there.

1964_442

iTrader: (5)

same problem of the OP here...

40-45 psi @ cold start up and 18-20 @ hot idle

and going to start figuring out in this order... other brand oil/oil filter , mechanical gauge, oil pump with new o ring.... til then i will accept what i already knew ... cam bearings lol

vettenuts

iTrader: (4)

Have a co-worker going through a similar issue with an 2007 3/4 ton 6.0 Silverado. Had a mechanical gauge verify the low pressure. He plans to have it swapped out next week. If you already bought the pump, swap it out.

WI Tom

It does have an aftermarket cam. Not sure on size but it does have a lope. That change anything? I'm not very good with motors. If it is a spun cam bearing what am I looking at for a repair? A whole new shortblock?

1964_442

iTrader: (5)

if it has been cammed , there is the possibility to have a pinched or bad installed oil pump o ring, if they remove the lower timing sprocket or the pump itself.

if its not too bad maybe you can change your cam bearings only ? have read some shops have made it even with engine still in car ... dunno... i have the same question about cam bearings

1964_442

iTrader: (5)

btw I did about 3 cam installs myself with no oil press drop in any of these cars and theres a ton of cammed cars out there running healthy even with big sticks

LS1MCSS

iTrader: (18)

OP, you're getting good advise from Thompson. The motor is on the verge of spinning a bearing(rod or main). Start saving your pennies for a rebuild or a new shortblock.

KCS

iTrader: (20)

Typically the oil pressure will get lower and lower each time the engine runs if the bearings are trashed. If it's consistently the same pressure, then your bearings are probably fine and its something else. There's plenty of variables that could cause low pressure. Start with verifying the low pressure with a good qulaity mechanical gauge.

WI Tom

That's what makes the most sense to me.

wildcamaro

iTrader: (15)

If you have engine torn down disassemble the oil pump...I got an l33 for $300 bc of "low" oil pressure but I turned out to be a bad pump, the machines surface below the gerotor was wiped out causing the issue...a new pump and the engine was back up to 30-35 lbs all day

WI Tom

Well I have a little update for anyone following.

I put the car up on my dads lift and hooked up a matco oil gauge today. Basically the gauge inside the car, above 20 psi, is about 5-10 psi high, which I'm not sure is normal or not. Below 20 psi it is right on.

I started the car cold and had 36 psi on the mechanical and 43 inside. The longer it ran, the higher the coolant temp got(oil temp isn't working) and the lower oil pressure went. It pains me to say but I think anyone who said clearances is probably right as there seems to be a correlation between higher coolant temps and lower oil pressure.

Anyone still think I should still throw the oil pump in it and pray?