Pretty sure my Vortec Max had a lifter collapse. It's been ticking even though the dealer told me it wasn't a problem(Probably just to send it down the road and hope that the warranty ran out, and it just did). I had also occasionally heard a sound that sounded like a wood pecker hitting a sheet metal roof, like a loose heat shield. The sound would only happen when AFM activated and light load between 55 and 60mph. I reported that to the dealer on my last trip(2 months ago) and they couldn't find anything and told me the tick wasn't an issue(yeah right).

Last couple days I've been hearing the metal rattle sound more often, same conditions only when AFM activated and only at light load between 55 and 60.

Yesterday while driving my CEL started flashing and the DIC displayed "Stabilitrak Off" and then "Service Stabilitrak". Of course this happened on a clover leaf off ramp in wet weather and the truck started to slide. Once I got parked I smelled an oil burning smell and the truck was running really shitty so I shut it down... and had it towed to a local shop.

I'm pretty sure I'll be told to kick rocks by GM and the dealer, which leaves me with the bill. So if I'm going to fix it... I'm doing it right and getting rid of that AFM crap.

The next step is figuring out what parts I'll need to eliminate the AFM. I'd like to keep VVT so I think that limits my cam options.

The other potential issue is the shop working on it isn't a performance shop so I don't think they'll be able to do any tuning.

 

A decent mechanic can swap the hard parts to delete AFM, the heads come off then access the lifter and be sure to inspect the cam too for damage. Once all is well here then and you need to hire a tuner to wipe out the codes that will fire for the AFM no longer in service etc. I'm a big fan of finding and hiring the BEST tuner you can afford so you can also get the performance all crisped up and shift points dialed in etc.


There are lists in the stickies for the nec parts you need for the AFM delete and lots of suggestions on where to find them here as you'll see with some searching. Unfortunate to hear about the problems, it happens as they push the envelope for improved mileage.

 

I figured out what parts I needed from Texas Speed. Just need to figure out the cam. I decided to go ahead and delete VVT to make it simpler.

This performance stuff is new to me, but I'm just trying to get my truck on the road without this AFM time bomb valvetrain.

Should I have the oil pump replaced as well?

 

Oil pumps on these trucks have been solid. But while you are there you may as well my luck sucks so I never not do something like that or it will bite me in the *** every time it's cheap insurance.

 

Timing chain replacement is never a bad call either. Oil pump should be ok. New pushrods of course, valve springs to match cam. I like VVT myself its not a detriment to anything and helps increase mileage and adds a bit more power too.

 

How many miles before this happened? Just curious. And it might be worth asking the dealer over the phone if they will do anything. But you would probably end up with more AFM parts if they do.

 

Your warranty inspections should be on file with the dealer. You should be able to get some help from GM with the repair even though the dealer wasn't smart enough to id the problem before it blew up.