2005 Rainier 5.3 V8 DoD question

We bought the truck with 170K miles back in April. I noticed it is using a good bit of oil- maybe 1 quart/1K miles. I installed a catch can and in a recent 1K mile round trip it had like 3 ounces of oil in it. The truck will occasionally smoke on startup, but it's not like a fogger (at all) going down the road. The truck is in really good shape for the miles and runs well.

Been doing some reading, and apparently the Displacement on Demand (DoD) was never enabled on these by GM since it is a short wheelbase model. I pulled the OEM tune and verified it is disabled.

My question- is the hardware still there? I read about DoD causing excessive oil consumption. I also read about disabling it helped cure a rear main oil leak. This truck has a minor leak towards the rear of the engine, not sure if it is the pan or rear main.

I recently overhauled a 2004 LM4 5.3 so I can fix this if need be, but would like more info before I pull anything apart.

Thanks for any advice or info.

Is the valley plate smooth or does it have all the veins for the DoD system??

I don't know. It's the wife's daily driver, so I can't pull the intake to check the valley plate right now. I do want to run a compression test on it though.

Open the hood and look at it, it's visible without removing anything.

Quote:

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Originally Posted by blindsquirrel

Open the hood and look at it, it's visible without removing anything.

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This piece here?
Attachment 102728
The truck is out of town right now, but if it is laid out like the LM4 I just rebuilt I'm not sure how I can see much of it with the intake in place.

See? It's right there. All you have to do is aim your eyes between the alternator & TB. Not nearly as complicated as you're imagining.

Attachment 102729

But let's do some deductive reasoning based on what is known about GM. They don't give the same RPO to two significantly different engines made in the same year. When GM added the DOD hardware to a L33, it got a new RPO: LH6. If your 2005 5.3L had been built without the DOD hardware it would have been called a L33, and L33 wasn't used in the GMT360/370 (SWB/LWB) in 2005. Hence, if you have a LH6, you have all the DOD hardware installed but not activated in the tune.

Makes sense, thanks. I'll look it over when it returns this weekend.

On my truck, it was very visible under the intake. I have the valley cover with "veins", so it's time to start collecting parts for the next project. One good thing is I have an L33 non-AFM cam leftover from a prior project. It is nearly identical to the LH6 cam in my engine according to the specs I've seen.