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"Check oil" Light

Posted: Thu Sep 06, 2018 10:55 pm
by Msitayem
Hi all, I recently picked up a 2011 Caprice 9C1 that had an LS3 swapped into it. When I got it it was throwing a few codes but I got them all figured out. One of the codes was P0521, so I replaced the oil pressure sensor and haven't had the CEL pop back up.

But after Driving the car around a bit today, I noticed when braking the check oil light comes on, but it'll go away the second I touch the gas.

Has anybody experienced a similar issue?

Thanks in advance!

Oh and I removed the oil pressure sensor and checked to see if there was anything that could be causing an issue there, and did notice that there's a noticeable piece of the valley pan gasket visible in that port.

Re: "Check oil" Light

Posted: Fri Sep 07, 2018 1:10 am
by elc32955
I've never laid hands on an LS3, but I'm pretty sure it has a dipstick for measuring oil level like the L77 has. Have you checked the level for correct initial set and/or excessive oil consumption with the stick? Nothing obvious (smoke, drips, etc...) out of the tailpipes right?

The other thing if the engine's been swapped is any harness issues that you're aware of? Dinged insulation that might be on the sensor line grounding out perhaps, touching just barely enough that varying the car motion might cause a make/break on the wire? Yeah, I'm grasping at straws but if the car was a 9C1 in patrol service, strange things can happen to wire bundles....

Anyway, just my .02 worth. Tons of more knowledgeable folks here then me!

Thanks
Eric

Re: "Check oil" Light

Posted: Fri Sep 07, 2018 6:01 am
by Msitayem
I have checked the oil and it seems a little high. I'm honestly not sure on the wiring but I'll follow everything tomorrow. Thanks for the tip!

Re: "Check oil" Light

Posted: Fri Sep 07, 2018 8:57 am
by Mooseman
That gasket should be replaced. You are probably losing pressure that way. At idle, the pump probably can't keep up with the leak but able to bring it back up at higher RPM but is probably still lower than it should be. It's leaking into the valley so that's why you're not seeing an oil loss.

Re: "Check oil" Light

Posted: Tue Sep 11, 2018 11:00 pm
by Msitayem
So i've changed the oil, put a mechanical pressure gauge on and i was seeing 20psi at cold idle. I put the stock sender back on, let the car warm up and plugged in a bluetooth obd2 scanner, and was monitoring everything using torque pro.


at idle i was seeing 4-10psi, and under light load it was at 20 psi. Getting on it a little bit i saw as high as 37 psi.


Here's my assumption, and i'll confirm this weekend when i drop the oil pan:

The guys i bought the car from saw the p0521, assumed it was a bad oil pump, swapped it out but pinched the O-Ring, this caused an actual low oil pressure issue, and here I am trying to figure it all out.

If anybody has any other suggestions they'd be much appreciated :)

Re: "Check oil" Light

Posted: Tue Sep 11, 2018 11:35 pm
by Mooseman
Another thought. If the pump was replaced with a regular LS pump, it will be low. I did that mistake on another vehicle and when the oil is older, the pressure is too low and triggers the code. The pump is supposed to be a high pressure and volume for DOD engines.

I still think it's the seal. If the PO didn't remove the valley cover during the swap, then that's why the problem never got fixed.

Re: "Check oil" Light

Posted: Wed Sep 12, 2018 12:53 pm
by Msitayem
Car has an LS3 swap, so no DOD.

I've decided the easiest method of fixing the oil pressure issue is to take it into a shop, and have them replace the oil pump.


Since they're already in there, I figured, why not swap the Cam as well :)

Re: "Check oil" Light

Posted: Wed Sep 12, 2018 4:36 pm
by CrashTestDummy
IIRC, there's also an issue with some LS engines, and I think it is the LS3, where one of the oil pump pickup bolts can work loose, causing oil pressure issues. Seems to be an issue on the Truck line. So replacing the pump should get that issue fixed, if it is the problem.

Re: "Check oil" Light

Posted: Wed Sep 12, 2018 9:28 pm
by Msitayem
CrashTestDummy wrote:IIRC, there's also an issue with some LS engines, and I think it is the LS3, where one of the oil pump pickup bolts can work loose, causing oil pressure issues. Seems to be an issue on the Truck line. So replacing the pump should get that issue fixed, if it is the problem.

Welp. Just my luck, I looked at the oil I drained yesterday. There was copper flakes in it, so looks like motor is going into surgery soon.

Gonna have the block rebuilt

Re: "Check oil" Light

Posted: Fri Sep 14, 2018 9:21 am
by CrashTestDummy
Well now you have an opportunity to verify the engine and hopefully clear up all the other issues that this system seemed to have lurking for you. ;)