I would not call those year engines awful (as I own one), but I understand the reasoning behind a hand fitted piston being a better idea. My '00 5.3 truck, 230,000 miles, has piston slap and even though it will easily outlast the body, it makes me want to use our '91 Camry more when it gets cold out so I don't have to hear the noise. I could care less if it is wearing 10 times faster than normal, just make it sound like my old 350 when started cold. My boss just traded in his '10 Silverado 5.3 AFM after two years because he was only getting 15-16 HGWY mpg. Did not use much oil as far as I know of, but then again it only had 25,000 miles on it. Bought a '12 Acadia instead. My truck usually gets 17-20 mpg with the "old" 5.3? I would disable AFM if I had it. This AFM stuff worries me in the long haul, repair cost wise. Now new trucks will have direct injection and variable valve timing to boot. Aluminum engines in trucks sound wrong. Cars yes, trucks no. That's just me though.
Originally Posted By: SteveSRT8
Originally Posted By: Doog
I had a 2002 5.3L and 2006 6.0L both horrible piston slappers...GM built some awful engines when they stopped having the pistons hand fitted on the assembly line. I had a 99 5.7L that was perfect and kick myself in the butt for ever trading it.
That was a silly comment. A bunch of those "awful" engines are in my driveways, one with 400k miles on it that works daily!
Piston slap is a hugely overblown issue that has never adversely affected engine life at all.