Oil Pump issue. Is the L99 just as prone?

[BLACK10]

Originally Posted by Nvincent4708

a LOT of work is involved with this though..pretty much the same amount of work as doing a cam swap minus having to pull a few parts.

plus the part is 1-200

not a lot for a mechanic shop, most shops can do a full cam swap and tune in 10-12 hrs. I think hes just being quoted a high price.:(

[tkrupinski]

The guys who had pump failures what was the mileage on your cars. Before I did my cam swap I contacted a few of the reputable builders on this site and was told, don't fix what is not broke so I reused my oil pump. No problems so far. From what I was told a pump usually fails before the mileage that was on my car, 10,000. I was a little shocked when the builders that I talked to said pump failures are rare and that the stock pump is actually a more reliable pump. If I have pump issues down the road I will post my mileage. 14,500 to date LS3.

[Rocky1974]

GM says the L99 is affected.

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
2009-2010 Chevrolet Colorado
2010 Chevrolet Camaro
2007-2010 GMC Envoy, Sierra, Yukon
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.

[Raptor626]

This ^ seems to have been posted in late 2009. Do you think GM addressed the issue in the 2011's?

[Synner]

No. Same pump and same design. No revised part number has ever been released.

[kmcd]

Originally Posted by Synner

No. Same pump and same design. No revised part number has ever been released.

However, the L99 and LS3 OEM pumps are different part numbers. I have still yet to hear or read about an L99 pump failing.

[Raptor626]

Here's the thing though. I'm unclear about what's causing the failure. Is it a faulty design, or are some just defective? I'm asking because the solution, which is to shim the relief valve, seems to imply that the design itself is causing the issue. So if the design is the core of the problem, why the f$@# hasn't GM changed it? Because if it is a design flaw, that means everyone will encounter this issue at one point or another.

I really hope it's just a defective few, because GM would be retarded not to alter the design in some way.

[Raptor626]

Originally Posted by Synner

No. Same pump and same design. No revised part number has ever been released.

Someone said in the thread I posted that the L99 has a "wider pump gear", I'm not sure if that makes a difference though.

[tkrupinski]

Originally Posted by Raptor626

Here's the thing though. I'm unclear about what's causing the failure. Is it a faulty design, or are some just defective? I'm asking because the solution, which is to shim the relief valve, seems to imply that the design itself is causing the issue. So if the design is the core of the problem, why the f$@# hasn't GM changed it? Because if it is a design flaw, that means everyone will encounter this issue at one point or another.

I really hope it's just a defective few, because GM would be retarded not to alter the design in some way.

What I was told is it is the bore in the housing that is not machined correctly or the finish on the relief valve bore is not polished fine enough. Call ADM he can explain it better. How many miles do you have on your car?

[Synner]

Originally Posted by Raptor626

Someone said in the thread I posted that the L99 has a "wider pump gear", I'm not sure if that makes a difference though.

The problem doesn't have to do with the pump gear, it's casting imperfections causing the pressure spring to stick and then not provide pressure. If there's no pressure to drive the pump it doesn't matter the size of the gear. Whether or not it has less casting imperfections is anyones guess.

Considering the number of LS based vehicles out there the failure rate is incredibly low. I plan on taking mine out and giving it a port/polish when I do my cam swap just to be safe. But if you're under warranty then don't worry about it. I wouldn't tear apart the front of my motor just for that.