I am shopping for a used chevy suburban. I have read that the active fuel management was used dating back as early as 2007 and has caused lots of engine damage if it is not deactivated.
I am looking at a 2007 suburban with 99,000 miles. It is a stock truck with the AFM and has the smaller V8 engine and 4x4. I don't want to buy a truck if the engine is already worn out. Is there any way I or a mechanic can check the truck out to know if it has preexisting engine damage from the active fuel management?
If the truck checks out OK, my plan would be to immediately have a mechanic permanently deactivate the active fuel management and drive it like that indefinitely.
Adding @Mod_Man to the discussion
You can compression test it as @Doc said, and I would recommend doing that.
The issues from AFM come from oil starvation. Tearing it down fully is the only way to know FOR SURE what the status is of the motor, but you can also get a mechanic's borescope and peak inside to get an idea. You can check for scuffs on the cylinder walls, etc.
At 100k miles, it likely has some damage if it has been running AFM the whole time.
AFM damages the camshaft. I think overhaul is the only way to inspect those.
MAYBE if you take off the valve covers, rockers, and lifters, you might be able to peer down the holes with a tiny camera. But I doubt you'll find anybody who will do that.
The most basic test I use for any ICE is the wet/dry compression test and then test the valve stem seals.
