Finally Jumped on the Oil Catch Can Bandwagon

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wsteele

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I see what you're questioning now!

No, the valve isn't just a second one that is simultaneously tied into the system along with the relief valve in the oil pump. Look at it as the AFM oil system being separate from the engine oil system. Through the series of solenoids in the VLOM, the AFM system and lifters are pumped up with the engine's oil pressure (that IS regulated by the relief in the oil pump), but then they are blocked off from it (by the solenoids in the VLOM) to stay pumped up. So, the lifters and AFM system are now pressurized and isolated from the main engine oil system. When AFM activates, the lifters need to be drained so they can collapse to shut off operation of those cylinders. The AFM solenoids in the VLOM open, releasing the oil pressure from the lifters. They collapse and the pressurized oil is directed from them to the relief valve in the oil pan. All the while the main engine oil pressure is remaining steady. So, the valve is only spraying when AFM activates and bleeds down the lifters. It is in no way connected to the engine's primary oil system.

Besides adding to the oily mist in the PCV system, the oil sprays on the bottom of the #7 cylinder, where it works its way up and gets burned, etc. leading to the carbon caking that sticks the rings, accelerates cylinder wear, etc.

Well, I guess that deflector does play an important role, as #7 spark plug looked like something out of the movie Alien, you barely could tell it was a spark plug. That was the cylinder that was the worst by far. At about 25K, after all the TSB stuff was done, I checked the plugs, they looked perfect.

I guess with AFM off, I will quit worrying about gummed up #7 rings (and go back to worrying about lifters... :)).
 
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Yes, but the PCV airflow is strong with the LS. Back in the day, you just needed a breather on the valve covers. Then, they made one breather in and the other breathe out, but it was mostly natural currents from the crankcase pressures. Now, they're using intake manifold vacuum to sort of "reverse supercharge" the evacuation of the PCV system. This increases the system's efficiency while giving it a way to be monitored (through the MAP sensor), keeping it a closed system to further satisfy the EPA.
I'm just saying why'd it take them from '07 till '10 or '11 (when they introduced the updated valve cover) to figure out this oil sucking problem?

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wsteele

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I'm just saying why'd it take them from '07 till '10 or '11 (when they introduced the updated valve cover) to figure out this oil sucking problem?

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I think the oil consumption problems didn't show up until like 30K+ miles (probably much higher for the average example) and then only on some vehicles. Once the problem is identified, big corporate structure takes a while to get the right people spooled up. Then there are the proposed fixes... yada, yada, yada. Just guessing from my experience working in big companies.
 

89Suburban

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I run an empty catch can with none off the scrubs in it and it does just fine and collects plenty of blow by. And is easy and simple to check and clean. BIG difference with the updated valve cover. Much less in "the can".

K.I.S.S.

Keep It Simple Stupid
 

iamdub

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I'm just saying why'd it take them from '07 till '10 or '11 (when they introduced the updated valve cover) to figure out this oil sucking problem?

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My guess, based on the ridiculous types of failures they're having on the 2015 and newer models, is that they're releasing these things prematurely. The Gen3 seemed to not have much of a problem, so they had no reason to change the cover for the Gen4. My only guess as to why it's a problem on the Gen4 is higher volume and resulting pressure for the AFM engines. Speaking of, AFM was a new thing in '07. We have the "first year model" of the new design. Considering the complexity of it and how well it works (aside from the longevity!), I could see how their focus would be elsewhere and oil spraying inside a crankcase, where oil is splashing around anyway, could be overlooked.
 

iamdub

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I run an empty catch can with none off the scrubs in it and it does just fine and collects plenty of blow by. And is easy and simple to check and clean. BIG difference with the updated valve cover. Much less in "the can".

K.I.S.S.

Keep It Simple Stupid

Yes! The old cover design is the root of the problem. The catch can should not be used as a substitute for getting the updated cover. It should be supplementary to the updated cover.
 

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