Kintla

Haven't taken anything apart yet, but assuming cam is shot too.

Is this an issue with 6.0 engines? I thought it was a 5.3 AFM thing. It's a 2008.

Anyway, recommendations on replacing cam or doing a rebuilt engine? Just talked to a mechanic who said he swaps in a rebuilt instead of replacing cams, not worth it he said.

Gumby22

AFM was introduced about 2007 but it wasn’t limited to the 5.3 engines.

To verify if you have AFM, look at the RPO label in the glove box - the engine code starts with L - match it here - GM RPO codes

You can verify if it’s the lifter or cam by removing the valve covers and looking at the rockers for the suspect cylinder. A cam lobe that’s worn down (or an AFM lifter that’s shot) won’t fully open the valve, assuming there’s no slack and the push rod isn’t just bouncing around.

To check for a collapsing lifter, Rotate the engine by hand until the valve is fully open and then stop and watch it - if the lifter is collapsing, the valve will slowly close from the spring pressure.

With or without AFM, the heads will need to come off to replace the lifters or cam.

As to recommendations of rebuilding vs. replacing - it depends on what kind of timeline you have and your comfort level on doing the work yourself.

Kintla

It's not AFM. You couldn't get AFM in a 2500/3500 rig, at least not that vintage. Not sure if later version had it as an option.

The question is contamination from cam wear that would justify dropping a reman engine in vs. just putting in a new cam on that side and 8 new lifters.

I've never heard of a 6.0 having a cam crap out, guess maybe it's not that uncommon. Bummed. Only has 130k on it.

Pulled the valve cover, identified which one is bad, pushrod is straight, but dial indicator shows less travel so assuming the cam is wore down from a stuck lifter.