2008 Yukon Denali Pressure relief valve deflector

02Lightning said:

I'm not sure if the oil pan has the relief valve or not until I get it off. I don't really know how that system works so I assumed the pump didn't have a relief valve and it was on the pan. Why would it need two? But again, I really don't know how the system works.

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They both are designed to open at X pressure to bleed off the excess pressure. The one in the oil pump is the "main" one that governs the pressure in the oil system as a whole. It is a longer spring style that compresses then starts bleeding off the pressure gradually and is supposed to be fully opened at X pressure to keep the maximum at that set psi. The one in the pan is for the AFM system. It's a pop-off design that is designed to open from the surge of pressure when AFM activates and abruptly drain and collapse the lifters. It doesn't gradually open to bleed down, it pops open at around 55ish psi. This is why it sprays and causes oil consumption and why GM came out with the deflector. AFAIK, the valve in the pump is also set around 55ish psi. If you have the valve in place, it's likely not doing anything at all except for preventing a 14mm hole from causing a drastic pressure loss.

I plugged mine with an oil plug meant for a drain pan. Just used red Loctite and torqued it in place with an aluminum crush washer:

https://www.tahoeyukonforum.com/threads/growing-up-doesnt-have-to-suck.93510/page-55#post-1427085

wjburken said:

The 6.2's that had "all the AFM components" to my knowledge, had the same ports in the block, which are blocked/sealed off, but that was it. My 2007 Denali did not have a VLOM or AFM lifters in it.

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Yours didn't have the towers cast into the block, either, did it?

Just Fishing said:

Plug it off.
It's just one more failure point imo.

The pump already has an internal pressure relief/bypass built in.

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Yup. And it works perfectly fine by itself on the Gen 3 engines for millions of miles and counting.

wsteele said:

If you are talking about the castings, I can see that. As @Geotrash and @wjburken have confirmed, they don't have the lifters, VLOM, etc. which is the stuff that would have to be present for the relief valve to make sense. The whole RPO code things is built around being able to split hairs about components not being installed that don't need to be (i.e. maximize profits).

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No these are actual engine shortblocks . The same shortblock in LT1 Camaro is the same as the trucks. They all have the full AFM hardware. Less complexity has its savings.

avalonandl said:

No these are actual engine shortblocks . The same shortblock in LT1 Camaro is the same as the trucks. They all have the full AFM hardware. Less complexity has its savings.

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Huh, I thought Camaro's did have AFM? Not sure why I thought that.

I AM surprised they are putting AFM lifters, cams and VLOM's in V8 Camaro's and not turning on the AFM software. The only thing I can deduce from the above, is there is no CoGs penalty to the AFM hardware over conventional components, because with modern IT systems controlling production, the idea that making one variant versus two saves money, if there were CoGs savings to be had, seems a little far fetched.

iamdub said:

Do the non-AFM engines even have the relief valve? If so, and if it were mine, I'd remove and cap it off since the oil pump has its own oil pressure relief and having that pop-off valve is just one extra possibility for a pressure loss if it were to leak. Although that's VERY unlikely to happen.

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I am ready to drop the oil pan. I do not have the oil deflector. Is it that important? I can wait. also you mentioned capping or plugging something as well. What is that? I know to drill out the rivits and use RTV on the 4 corners. Am i missing something? I do not have VVT and are deleting the AFM-DOD.

Gilla said:

I am ready to drop the oil pan. I do not have the oil deflector. Is it that important? I can wait. also you mentioned capping or plugging something as well. What is that? I know to drill out the rivits and use RTV on the 4 corners. Am i missing something? I do not have VVT and are deleting the AFM-DOD.

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The oil deflector is attached to the pressure relief valve in later models. You can safely remove the valve and plug the hole since you’re deleting AFM. I decided to buy a new valve and reused the old deflector when I did mine since I was going with a high volume pump, but if I had it to do over again I would have just plugged it. If you decide to keep the valve though, definitely get the deflector.

Gilla said:

I am ready to drop the oil pan. I do not have the oil deflector. Is it that important? I can wait. also you mentioned capping or plugging something as well. What is that?

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The valve in the oil pan that we're discussing is the pressure release for the AFM system. When it releases, the oil would spray out of a small hole, making it almost atomized and more easily carried by the airflow of the PCV system. The oily air would "ride the currents" and follow the PCV circuit into the intake manifold, meaning oil was being deposited into the intake manifold tiny droplets at a time over thousands of miles. GM came up with a deflector shield to cover the valve so that when the oil sprayed, it just hit the deflector and dripped down as a heavy stream of oil into the sump with the rest of the oil. If you're deleting AFM, you won't need the shield. That valve won't be operating and can be left as-is or removed and replaced with a plug. I think I used an aftermarket replacement for a Honda Accord oil pan drain plug. Pics, part number and description are here:

https://www.tahoeyukonforum.com/threads/growing-up-doesnt-have-to-suck.93510/page-55#post-1427085

Gilla said:

I know to drill out the rivits and use RTV on the 4 corners. Am i missing something? I do not have VVT and are deleting the AFM-DOD.

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That's to remove the factory oil pan gasket. Not related to the valve subject. But, it's good that you're aware of the sealant required at those four seams.

Thank you!!