I did a little reading on the GM "Affordable Fuel Mgt." engines after they were mentioned in my earlier post re a used Silverado. Don't want that in a used vehicle. What year did GM start with the AFM engines and when did the problems stop? The only years I'm seeing mentioned are 07&08. Thanks.

I looked further into this. AFM was credited with causing excessive oil use/loss and as best I can tell 2007 was the first year for truck engines. GM finally developed some sort of "shield" to prevent oil loss for 2007 through 20011 vehicles but it hasn't completely eliminated the problem.

Granted I got this info from a tundraheadquarters.com article written in Sept 2013 but it appeared pretty well documented with info that came from GM and other sources. The article also indicated Honda was having some problems with similar technology.

I guess killing the AFM on engines that have it is a big deal. My 2010 Silverado LTZ-Z71 has it and I've experienced no problem with excessive oil loss or any kind of acceleration lag.

Most tunes, like the popular Black Bear Performance will eliminate the AFM, if not wanted. http://www.blackbearperformance.com/

Personally, my 2010's mileage and performance is so darned good that I've not investigated trying to improve a vehicle that has been perfect in ever way.

kd

Start here .

The shield is to prevent excess oil from being sprayed on the underside of the pistons in the deactivated cylinders. The rings would get gummed-up and seize, allowing oil to be burned.

Mostly what I've heard is the problems are way down on '12 and later models. They did get mine fixed, eventually, and it has held for about 60K miles. I'd still be wary, though. I'm not fond of them having to do open heart surgery on my engine 3x in the first 75K miles.

FC

Had a new '06 GMC Z71 and just swapped the '10 Silverado Z71 that was bought new. Both were somewheres in the 55,000-60,000 mile range when traded.

Both had the 5.3L aluminum V8. Only the '10 had the "fuel" thingus that cut it back to a V4 when cruising. Zero oil consumption issues with either truck and the '10 went over 6,000 miles several times between oil changes. Straight 5W30 oil, no synthetic.

Good link.

2007 was first year. Wife bought a new z71 then. Got rid if it at 95,000 miles. It went through a lot of oil, first noticed at about 60,000 miles. She was going to do the oil consumption testing before 100k warranty was up but we traded it off instead.

Personally know 4 others that HAD 2007 5.3l and every one consumed oil.

There is a reason if you google search "2007 5.3l" that google then auto populates with "oil consumption" as most popular search. I don't know when/if they solved the issue, as I haven't been in the market for a gm 5.3 since then.

Also, my 2003 5.3 was 225,000 miles of trouble free truck. Regret getting rid if that one last year.

2010 GMC with about 66k on it and no oil consumption problem here.

My 2011 5.3 uses about a quart every oil change. It needs it at about 4k and I change oil about 6.5 to 7k miles. Use Mobil 1 5-30. Has 120k on it.

Thanks to all for the info. Looks like 2007 was the first year. Some vehicles and owners had problems, some didn't but it's something to consider if you're looking to buy a post 2007 used vehicle that had AFM.

It's nothing you can find out in a test drive, either.

Possibly a CarFax, and maybe by having a dealer service dept. run the VIN. If GM paid for the fix, it would show up there. Still, you don't know if the "fix" that was used, actually worked.

2006 and earlier, though, were solid engines.

FC

My '07 Tahoe had the 5.3 with AFM. I had 100K on it when I sold it. No issues with oil consumption.

my 07 sierra had the 5.3L with AFM it lassted to 173,000 and the tranny went out