LS3 Oil Pump relief valve (No oil pressure)

[4packet]

Car is currently in Holland awaiting transport back to the UK.

Attended a trackday at Zandvoort. 90degF ambient which is the hottest the car has ever experienced. Did a couple of sessions. 2nd session the water peaked at 230degF and oil at 268degF(pre cooler). Samberg rad, single stock oil cooler with 99 bumper. Had the air con on also.

When the water temp peaked I ran 2 laps to cool it down before coming in. At low revs in top gear the oil pressure alarm (Spa gauge) pinged at 7 or 8 psi. I lightly blipped the throttle and instantly saw 40psi. When parking in the garage I could hear the alarm again and saw 7/8 psi. Switched off, then keyed on 5mins later and noted the water temp had risen to 226degF. Fired it up to circulate the water and the oil pressure read zero so switched off. Plugged in efilive and restarted which confirmed both GM and Spa sensors were reading zero oil pressure. No change to engine running or noise btw.

Left to cool some more and pulled the oil filter off. On crank only (pulled fuse on the RLTC) there was no oil flow so called it a day.

On return have found the below info on the net. Seems likely given my experience. Since putting the car on the road I have occasionally noticed a low blip in oil pressure at low rpm. Typically when coming off load, but oil pressure returns when revs are increased or clutch is pressed. Anyone got any experience of this or suggestions. My current plan is to fit a new stock GM pump and check for any contamination in the oil.



http://www.camaro5.com/forums/showthread.php?t=72458

PIP4158C: Low Oil Pressure Due To Seized Oil Pressure Relief Valve - (Dec 29, 2009)


Subject: Low Oil Pump Pressure due to Seized Oil Pressure Relief Valve

Models: 2008-2009 Buick Lacrosse, Allure (Canada Only)
2007-2010 Cadillac CTS-V, Escalade
2007-2010 Chevrolet Avalanche, Corvette, Silverado, Suburban, Tahoe
2007-2008 Chevrolet Monte Carlo SS
2007-2009 Chevrolet Impala SS, Trail Blazer
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2010 Chevrolet Camaro
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2009-2010 GMC Canyon
2008-2010 Hummer H2
2008-2010 H3 Alpha
2008 Pontiac Grand Prix GXP
2008-2010 Pontiac G8 GT
2007-2009 Saab 97x
with the Following Aluminum V8 Engine RPOs:
L76, L77, L92, L94, L99, L9H, LC9, LH6, LH8, LH9, LS2, LS3, LS4, LS7, LS9, LSA, LZ1

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:

Some customers may complain of low oil pressure, no oil pressure, and/or engine noise, which may be the result of a sticking oil pump pressure relief valve. In some instances, this may occur intermittently if the valve frees up when the engine cools down.
Recommendation/Instructions:

If SI diagnosis isolates low mechanical oil pressure at the oil filter housing and oil pressure sensor, replace the oil pump, flush the oil cooler lines (if equipped), clean the inside of the oil pan, change the oil and filter, and re-evaluate the concern.

Notice: If an engine noise is noticed after replacing the oil pump, follow the SI diagnosis and repair the engine as necessary.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

[quinns]

My dads pickup had that tsb/pi done on it. Was exactly what it says.

[4packet]

I'm assuming he caught it in time and the engine was OK. Just a pump change?

Just trying to figure out what parts I need for a pump change. I'm against the clock as the car needs to be ready for a trackday at Spa/Nurburgring and it could be up to 4 weeks before I get the car back.

[quinns]

Motor likely didn't enjoy it but he kept driving it for a week because it was in the middle of harvest. I finally had to tell him to stop being a numpty and get it fixed. It was intermittent so most of the time he had oil pressure, I'm amazed it didn't get screwed.

I imagine you just need an oil pump, front cover gasket, o ring for the pickup, front main seal, and water pump gaskets. May as well do a cam swap while you're in there  . You likely could get away without replacing all the gaskets and seals but for the price of them I feel its worth it.

[Ericsworld]

Exactly how common is this relief valve/oil pump issue with LS3s?

A quick search will yield a few threads with complaints, but it can't be as prevalent in real life as it is on paper...?

[quinns]

I doubt that its common. My dads trucks the only one I've heard of it happening to until this thread. IF that's what 4packets problem even is.

[4packet]

I don't think it's common as such, but it seems to be an acknowledged failure. It's a common pump design across all the LS engines, although some have a higher flow.

This gives a good overview of the issue and pump design - can ignore the latter half.


Just glad I had the external audible alarm active on the Spa gauge, otherwise I may not have spotted it so quickly.

[4packet]

Got the car back over the weekend and confirmed the issue.

Unscrewing the relief valve spring led to a thunk sound (plunger firing closed). Pulled the plunger out and it had very obvious scuff marks on one side.

Gettting the oil pan off is a bit of a pain, although could probably wriggle the pick up tube off/on by just dropping the sump onto the subframe. I wanted to check everything was clean inside the pan though.