Finally Jumped on the Oil Catch Can Bandwagon

[Jason in DLH]

I am a little unclear which of the 2007-2009 Denali's came with all the AFM components and which didn't, but in any case, if it were me, I wouldn't bother to install the deflector (if I did have all the bits installed), unless I was dropping the pan for some other reason and even in that case, I probably would just plug the relief valve versus install the deflector, again, if the AFM stuff was there and just not turned on.

The part number you searched is the right number, GMpartsdirect just has the wrong picture (it looks like they are showing a bank 2 cover, not bank 1). If you search your model year, etc. on Rock Auto, it will show the correct cover.

Great, thanks for the info!

 

[Jason in DLH]

I see Rock Auto is still selling the “Original Design” (the 2nd part). Not sure why anyone would purchase that?

 

[Rocket Man]

I see Rock Auto is still selling the “Original Design” (the 2nd part). Not sure why anyone would purchase that?

View attachment 274334

Cheaper? You know, for shops to make money.

 

[wsteele]

I see Rock Auto is still selling the “Original Design” (the 2nd part). Not sure why anyone would purchase that?

View attachment 274334

That is odd, that they list it as the original design, but with the updated design number as a cross reference.

BTW, although yours is not an AFM engine if you haven't read it over, below is a link to one of the oil consumption TSB's (not sure which rev, but they are very close to each other in content).

I don't think anyone (perhaps including GM engineering) actually knows for sure if the AFM pressure relief valve is an actual contributing factor in the stuck ring and oil consumption saga (and hence, if it is, if the deflector is worthwhile). My engine which did have the worst case scenario as per the TSB was driven exactly as the TSB calls out as the worst case (first 60,000 miles in tow mode, with obviously higher than normal RPMs for extended periods of time). In addition, my oil pressure has always been on the high side, so if flying oil (either out the valve cover through the PCV and into the intake, or out the AFM pressure relief valve) was a factor, mine surely would qualify as the copy book case.

In any case, if your engine is pushing a lot of oil out the PCV and into the catch can, I would have to believe installing the updated valve cover is a good bet.

https://f01.justanswer.com/camerontech/b2a842c0-18fc-4828-85f1-e66f6588acba_SB-10065824-9133.pdf

 

[donjetman]

My Denali L92 6.2 doesn't have "all" the AFM hardware. My valley cover is smooth. Only the early production L92's had “all” the AFM hardware (Built Prior to April 1, 2006 with 6.2L Engine RPO L92 These early engines were built with AFM Hardware but the AFM system was disabled) from Bulletin No.: 10-06-01-007C.

TSB 10-06-01-008M
https://f01.justanswer.com/ebrock63...il+Consumption,+MIL+ON,+Engine+Runs+Rough.pdf
was confusing when it talked about the deflector, but the deflector only cost $8, and I was pulling the pan away to change the pickup tube oring, so I install it.

Here's a thread with pics that I did of what my sparkies looked like, no bueno for chit:
https://www.tahoeyukonforum.com/threads/sparkies-no-beno.108579/
I cleaned them in my media blast cabinet and they are still in my engine 35k miles later.

 

[wsteele]

My Denali L92 6.2 doesn't have "all" the AFM hardware. My valley cover is smooth. Only the early production L92's had “all” the AFM hardware (Built Prior to April 1, 2006 with 6.2L Engine RPO L92 These early engines were built with AFM Hardware but the AFM system was disabled) from Bulletin No.: 10-06-01-007C.

TSB 10-06-01-008M
https://f01.justanswer.com/ebrock63...il+Consumption,+MIL+ON,+Engine+Runs+Rough.pdf
was confusing when it talked about the deflector, but the deflector only cost $8, and I was pulling the pan away to change the pickup tube oring, so I install it.

Here's a thread with pics that I did of what my sparkies looked like, no bueno for chit:
https://www.tahoeyukonforum.com/threads/sparkies-no-beno.108579/
I cleaned them in my media blast cabinet and they are still in my engine 35k miles later.

On some of the threads I have read, I think some who say their engine has AFM hardware, are referring to the oil galleries cast into the block for AFM function, versus having everything VLOM, AFM lifters, AFM cam, etc.

Yours did have an AFM pressure relief valve then? Interesting, so no VLOM, but a pressure relief valve.

I have never seen an oil schematic that shows how the AFM pressure relief valve works separately from the oil pump relief valve. So for me, the AFM relief valve seemed redundant, but maybe it is there more for timing of over pressure relief, not sure.

Given yours had the valve, but no VLOM, maybe plugging it versus installing the deflector is a bad idea after all.

I guess the conservative approach would always to install the deflector if it is there. Certainly no downside to that approach.

I clearly don’t know if it was one or many things that cured my oil consumption, but I was losing a lot every 1000 miles. After the full TSB treatment, nada. Which sure made me happy.

 

[iamdub]

This talk is confusing me because the Vortec name has been used for the LS truck engines. My 02 LQ4 is a Vortec, my 08 LY2 is a Vortec.

I agree. But, the name "LS" supersedes "Vortec". The older engines were the first of the "Vortec", so they keep that title exclusively and can't be called an "LS".

Some things you just gotta let slide. Just like people saying they drive a Cummins, Duramax or Powerstroke. Those are engines and you don't actually drive them. You drive a Ram (or Dodge), a Chevy or GMC, or a Ford. Or, people referring to their four wheeler or side-by-side as a "bike".

 

[iamdub]

On some of the threads I have read, I think some who say their engine has AFM hardware, are referring to the oil galleries cast into the block for AFM function, versus having everything VLOM, AFM lifters, AFM cam, etc.

Yours did have an AFM pressure relief valve then? Interesting, so no VLOM, but a pressure relief valve.

I have never seen an oil schematic that shows how the AFM pressure relief valve works separately from the oil pump relief valve. So for me, the AFM relief valve seemed redundant, but maybe it is there more for timing of over pressure relief, not sure.

Given yours had the valve, but no VLOM, maybe plugging it versus installing the deflector is a bad idea after all.

I guess the conservative approach would always to install the deflector if it is there. Certainly no downside to that approach.

I clearly don’t know if it was one or many things that cured my oil consumption, but I was losing a lot every 1000 miles. After the full TSB treatment, nada. Which sure made me happy.

The one for the AFM is to relieve the pressure spike when the AFM system activates (or deactivates?). The one in the oil pump is to regulate the total system pressure. Pressure is a result of restriction. When you suddenly have eight blockages or leaks in a system, the pressures can swing wildly.

 

[wsteele]

The one for the AFM is to relieve the pressure spike when the AFM system activates (or deactivates?). The one in the oil pump is to regulate the total system pressure. Pressure is a result of restriction. When you suddenly have eight blockages or leaks in a system, the pressures can swing wildly.

That is the way I have always understood why the AFM pressure relief valve was there. What I never got was why high RPM operation caused that valve to spray oil. To me, the pressure spiking when the solenoids closed (when the system was moving from V4 to V8 mode) made sense, as, like you said, shutting the oil flowing to the eight AFM lifters must create some sort of pressure spike. But that isn't happening during extended high RPM operation (like when I was towing the big old trailer in trailer mode all those years).

I think I am still really puzzled about that AFM relief valve and when it is normally open.

 

[iamdub]

So tonight was the first time driving with the new Catch Can. Drove 20 minutes (a few WOT runs to clean things up ) and I can’t believe how much oil is in the can just from 20 minutes of driving....

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Good lawd! You at least need the updated rocker cover. I'd do the upper engine cleaning TSB since your engine has been burning so much.