Did 2007 Denalis have AFM in the 6.2 ?

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91RS

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I agree that oil changes are really important in AFM engines, but oil isn't the only issue. The metal used in the lifters also flake off and trash the cam, and the PCV system doesn't help either.

The real problem is the heat created in the AFM cylinders when they’re disabled.
 

BG1988

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It’ll only prolong the inevitable. My uncle bought his Silverado new in 2008 and the oil was changed every 5k and it started using around 80k miles. He got 45k out of the Goodyear LS2 tires because we rotated them and kept it aligned properly but we couldn’t stop the oil consumption.
sorry 5 k miles is too long

2500-3k miles is what you want....
any signs that it is getting dirty = bad

and you really don't want to cheap out on the OIL or FUEL or filter

These things are in the engine...

I know the hybrid is different and the engine hardly does anything (mostly off loaded to the electrical motors) and in AFM mode aka v4. most of the time.


that is why I run 91 octane from chevron as the v4 mode performs better with it. less down shifts and less v8 mode.. v4 and v8 are seemless and unnoticeable .

most of the time i have to check the DIC see what mode it's running in.. haha

The real problem is the heat created in the AFM cylinders when they’re disabled.
that is why the oil wears out faster higher oil temp = more wear to the oil... varnish then the little tubes seal up
 

91RS

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It would still just be delaying the inevitable even changing the oil at 3k miles. The low-tension rings didn't work and that's why the replacements aren't low-tension. There's also a reason the newer AFM engines will only stay in V4 for X amount of time before coming out and staying in V8 mode a bit to keep the heat down and the ones with AFM on all 8 cylinders will bounce around and not do the same cylinders every time. So far, the newer engines (LT based) don't seem to be having the oil consumption issues but only time will tell. I still wouldn't buy one of the newer trucks because I don't think the quality is there.
 
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avalonandl

avalonandl

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I wasn't trying to start a debate. Its just that the vehicles I am loking at are higher mileage (over 120k) and AFM at that age and mileage is more prone to failure.

Changing oil at 3k miles? How nice, a throwback to the 70's....

Use a Wix filter and Mobil 1 You should get 6k or more based on the oil life monitor.
 
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91RS

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It's not really the internet without debate, is it?
 

swathdiver

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The real problem is the heat created in the AFM cylinders when they’re disabled.

There's also a reason the newer AFM engines will only stay in V4 for X amount of time before coming out and staying in V8 mode a bit to keep the heat down

The Gen IV engines have a 10 minute time limit for V4 operation. Are the Gen Vs less?

So more heat is generated from a non-firing cylinder than one making power? o_O
 

okfoz

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I have 188K on my 2007 with AFM and no issues with the engine. I give it regular oil changes with full synthetic oil. I have also done a crank case oil Flush where the oil change place drains all of my oil, then puts in a cleaner/oil and run the engine at idle for 15 min, then drain and refill with oil of my choice. Done this twice and any slight misses or issues have completely gone away afterwards.

As for the oil consumption I was told that the reason why they consume oil is the rings more than anything. They use a metal for the piston rings that shrinks causing larger gaps, it increases fuel economy but the down side is it consumes oil. My truck consumes about 1 quarts every 1500 miles...
 

R3cord303

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I have 188K on my 2007 with AFM and no issues with the engine. I give it regular oil changes with full synthetic oil. I have also done a crank case oil Flush where the oil change place drains all of my oil, then puts in a cleaner/oil and run the engine at idle for 15 min, then drain and refill with oil of my choice. Done this twice and any slight misses or issues have completely gone away afterwards.

As for the oil consumption I was told that the reason why they consume oil is the rings more than anything. They use a metal for the piston rings that shrinks causing larger gaps, it increases fuel economy but the down side is it consumes oil. My truck consumes about 1 quarts every 1500 miles...
Have you installed the updated drivers side valve cover? I did that on my 07 and it reduced my oil consumption to about 1/3 of what it used to be. I burn a little over half a quart every 2,000 miles now. Can't wait to turn off AFM and hopefully that will help. Would really like to delete it this summer.
 

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