Hello all. New guy here. Ive been working on diesels the last 8 years but a good friend of mine came to me with his Tahoe. Its a 08, 170K on the clock, 5.3 LTZ with a tapping noise. Not a tick and doesnt sound like a rod knock. From what ive read on other forums these AFM lifters seem to cause similar issues. Im not up to date on this AFM stuff so im hoping someone could shine some light on it for me, and I also want to make sure im equipped to do the job before tearing it down. Any special tools needed or certain things to watch for? It has fresh oil and filter so I got in and reved it up while in park. The noise seemed to go away after about 2000RPM, but comes back any less than that. Oil pressure is good. I havent tried to drive it in manual yet to see if it changes anything. I plan on checking the cam, replacing all lifters and all new gaskets and head bolts.

 

ton of information on AFM here.


if the rest of the oiling system has survived you can get away with a cam and lifter swap. Then have the AFM deleted.