2008 Yukon Denali Pressure relief valve deflector

[02Lightning]

I'm getting ready to do my oil pan gasket, then replace my oil pick up tube O-ring while I'm there. I'm thinking my car does not get the pressure relief valve deflector, because I do not have DoD. Should I go ahead and put it in there anyway? I am also replacing the oil cooler block off plate gasket, anything else I'm missing?

 

[iamdub]

I'm getting ready to do my oil pan gasket, then replace my oil pick up tube O-ring while I'm there. I'm thinking my car does not get the pressure relief valve deflector, because I do not have DoD. Should I go ahead and put it in there anyway? I am also replacing the oil cooler block off plate gasket, anything else I'm missing?

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.

 

[02Lightning]

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.

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.

 

[wsteele]

Without AFM, oil isn't going to be directed through the AFM system (it is oil pressure in the AFM system that activates the AFM lifters and shut the valves off in the AFM cylinders), so there is nothing to deflect out the relief valve (which is there to assure over pressure in the AFM system doesn't happen).

I have heard conflicting accounts of what AFM components are there or not there in those model year Denali's. I was always shocked to hear when someone said they had all the AFM components, but were turned off. Knowing every penny counts when building mass volumes of cars, it never made sense to me that GM put the AFM components in those 6.2L engines but didn't turn them on.

In any case, as @iamdub said, if it were me and it was there, I would pull it out and plug it.

 

[wjburken]

Without AFM, oil isn't going to be directed through the AFM system (it is oil pressure in the AFM system that activates the AFM lifters and shut the valves off in the AFM cylinders), so there is nothing to deflect out the relief valve (which is there to assure over pressure in the AFM system doesn't happen).

I have heard conflicting accounts of what AFM components are there or not there in those model year Denali's. I was always shocked to hear when someone said they had all the AFM components, but were turned off. Knowing every penny counts when building mass volumes of cars, it never made sense to me that GM put the AFM components in those 6.2L engines but didn't turn them on.

In any case, as @iamdub said, if it were me and it was there, I would pull it out and plug it.

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.

 

[Geotrash]

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.

This is correct. The towers are there, cast into the block, but blocked off with the flat valley pan with the o-rings for the tops of the towers. The engine has standard lifters in that case. I don't know for sure whether they have the relief valve in the pan, but my bet is that they do because the VVT system works on oil pressure as well. Either way, the deflectors are cheap so buying one to have on hand for the job isn't a bad idea. Removing the valve and blocking the passage may be fine too, but they engineered it into the system for reasons I don't fully understand, so when I dropped the pan on my 2012 for a cam swap, I replaced the valve with a new one and left the deflector in place, even though I had deleted AFM and VVT. It might have been a silly thing to do, but my oil pressure is better than ever - never drops below 35-40, nor goes above 55.

 

[Just Fishing]

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

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

 

[avalonandl]

I have heard conflicting accounts of what AFM components are there or not there in those model year Denali's. I was always shocked to hear when someone said they had all the AFM components, but were turned off. Knowing every penny counts when building mass volumes of cars, it never made sense to me that GM put the AFM components in those 6.2L engines but didn't turn them on.

In any case, as @iamdub said, if it were me and it was there, I would pull it out and plug it.

You will be shocked to learn that all LT1 shortblocks GM is producing have AFM components whether its turned on or not. It reduces complexity on their engine assembly line and part numbers that need to be inventoried especially for a large expsensive part (an engine).

My 2017 Camaro SS is a 6 speed manual and AFM is turned off (thankfully) from the factory. The Automatics its turned on.

 

[wsteele]

You will be shocked to learn that all LT1 shortblocks GM is producing have AFM components whether its turned on or not. It reduces complexity on their engine assembly line and part numbers that need to be inventoried especially for a large expsensive part (an engine).

My 2017 Camaro SS is a 6 speed manual and AFM is turned off (thankfully) from the factory. The Automatics its turned on.

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).

 

[swathdiver]

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.

I have heard conflicting accounts of what AFM components are there or not there in those model year Denali's. I was always shocked to hear when someone said they had all the AFM components, but were turned off.

The very earliest 6.2 motors made before April 2005 had all of the hardware for AFM but the system was turned off in the tune. This would likely include some Escalades as well but in total, not many were configured this way.

 

[iamdub]

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.

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

 

[iamdub]

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.

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

 

[iamdub]

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

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

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

 

[avalonandl]

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).

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.

 

[wsteele]

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.

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.

 

[Gilla]

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.

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.

 

[Geotrash]

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.

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.

 

[iamdub]

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?

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

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.

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.

 

[Gilla]

Thank you!!