[PunchT37]

Originally Posted by dataway

Well ... I'll have to give the 5.3 a vote of confidence. My 2011 has 110k on it now and purrs, still an extremely quiet engine. I've thought I've felt the AFM system kick on/off maybe a dozen times in those years, I've never heard a change in exhaust note. It's got probably 30,000 miles of towing, 6,000 lbs or less. Full tow package, HD cooling etc., 3.55 (approx) rear end. Nothing but Mobil 1 it's entire life. Got new plugs, wires, alternator, coolant, fuel pump and some evap components at 100,000. Nothing was wrong, just preventive replacements. Never thrown a single code (knock wood).

Wonder if driving style, or type of driving effect the longevity with the AFM system. Seems like it would kick on most of the time on the highway .. 80% of my highway miles have been towing where it probably doesn't trigger the AFM much at all. The truck has been used primarily for medium length local travel in situations where the AFM doesn't have much of an opportunity to stay on for long.

Brakes really suck though.

They will never be as reliable as the old LM7 that I still have. But, my brother has a 2007 5.3 with AFM that has 138,000 miles. Runs like a clock. Very quiet, no oil leaks, etc. My co worker has a 2010 Tahoe with those lifters. Same thing. It has close to 200,000 miles. Absolutely quiet when it runs and dry as a bone as far as oil leaks.


So, for all the failures,[even though there are many more than the past] how many are running around with no problems?


It`s not stopping me from buying a 2025 truck with the 5.3 for retirement.


I will run 5w30 instead of the 0w20 they call for. Funny how they call for 5w30 in the 4.3 and 6.6, and some vette and camaro 6.2`s. 0w40 in others with the same parts. Course, I`m starting from NEW.



It`s all about CAFE.


By the way, the AFM versions have an oil screen in the valley tray to keep trash out of those lifters. If it`s dirty, it will cause a drop in pressure to those lifters. So, if ya got one, change it.


https://www.melling.com/wp-content/u...s-3.1.18-1.pdf



DFM has a different block without all the stuff in the valley tray.


They don`t call it a valley tray but hey, this is a Pontiac forum after all.