Low Oil pressure issues. Oil pump?
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 23
Likes: 0
Low Oil pressure issues. Oil pump?
Having some low oil pressure issues with my c6 Grandsport. When I start the car it stays at 4-6 for a sec then rises to 40. If I start the motor and pat the gas a little bit it rises immediately. Once warm oil pressure drops to 16psi. But while I’m driving it’s normal, around 35-40. Oil pressure raises to 50-60 high rpm. Oil filter is a Mobil one. It’s the correct one. Put a thicker oil in, no change in idle oil pressure when warm. Thinking it’s either a issue with the oil pump or cam bearings at this point. Any insight?
Safety Car
Joined: May 2006
Posts: 3,696
Likes: 493
From: Potomac MD
That does seem a little low. How long have you had car if a long time is this an issue that has suddenly come up or a gradual decline. What is pressure when oil is at 200 degrees not sure GS has it but you can toggle through the speedo chart there and it should give oil temp. Is the 16 psi at idle I presume? The reason I ask on the history is if it was say 30 psi 2 years ago at idle and now 16 then I would say you have an issue. Has car been modified at all. Sounds like at a minimum you need a new pump (assuming the decline over time is true) so take old pump and disassemble hopefully they can find something if not pull the pan and take a bearing cap off. Unfortunately none of this is an easy job. You can try a pump first and if it does not change immediately within the test period stop do not pass Go do not collect $200 and then motor needs work. Another thing you might look at is did one of your DOD seals go bad and oil is going out one of those holes. The LS7 does not have DOD holes but I think the LS3 does have displacement on demand holes under the valley tray.
Team Owner
Joined: Jun 2005
Posts: 46,295
Likes: 2,596
From: Northern, VA
St. Jude Donor '15
"In honor of jpee"
good post above but still need more info. how long have you owned the car? from new? what is mileage on car? have you checked for any codes? any leaks? manual or auto trans?
not only has the car been modified, but what work has been done to the engine/trans on the car, or any other replacement parts in/on the engine? non-stock parts? any tune to the car/trans?
Personally, I don't know if LS3 does have DOD holes since it's not a DOD engine. I also don't think having thicker oil in there is a good idea unless you live in hot climes with the car.
not only has the car been modified, but what work has been done to the engine/trans on the car, or any other replacement parts in/on the engine? non-stock parts? any tune to the car/trans?
Personally, I don't know if LS3 does have DOD holes since it's not a DOD engine. I also don't think having thicker oil in there is a good idea unless you live in hot climes with the car.
Burning Brakes
Joined: Aug 2014
Posts: 1,240
Likes: 258
From: Tampa FL
As a test:
You might check oil pressure with direct reading guage from local parts store. (Autozone loner tools)
Easyer and cheaper would be replacing oil sending unit. Top rear of engine under intake maf.
Rather than oil pump replace. I also think not, for thicker oil !
You might check oil pressure with direct reading guage from local parts store. (Autozone loner tools)
Easyer and cheaper would be replacing oil sending unit. Top rear of engine under intake maf.
Rather than oil pump replace. I also think not, for thicker oil !
Racer
Joined: Dec 2013
Posts: 258
Likes: 5
From: Columbia SC
Yes do this first before you go ripping into the engine, may be as simple as the sending unit going out.
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 23
Likes: 0
I’ve owned the car for around 6k miles. Had the oil changed recently and that’s when the issue came about. Only has 57k on it and it’s a wet sump auto car. I’m going to check the pressure with a mech gauge today. Once at 200-230 it carries between 15-18psi at idle. Cold it isles at 40psi. I’ll post a video of the idle in a sec it I can.
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Safety Car
Joined: Jun 2017
Posts: 4,786
Likes: 425
From: North Georgia, USA
Add overfilled oil to thhhe list fpossible causes. Oil foam doesn't build pressure like liquid oil. Overfill it to the point where the crankshaft whips it into a foam and you'll have low pressure issues.