Silverado lifter tick

[Zack Yakemovicz]

So I got a 09 Silverado 5.3 vin M. I had a real bad misfire on cylinder 4 so I started by swapping coils, misfire did not move, tried plugs, nope, cylinder leak down then led me to the cam or lifters. So I bought a lifter set of 8 regular, and 8 AFM. Started to take it apart and found a flat spot on cylinder 4s AFM exhaust valve lifter, then I noticed the cam was ruined from the lifter, got a new factory cam from Chevy and installed everything fallowing Mitchell shopkey to the T. Started it up and it went from sounding like a 5.3 to sounding like a duramax. The tapping is on all AFM lifters. When I go in and deactivate the AFM lifters with my scanner the tick goes away completely. No misfires, runs great, just ticks. I since the. Went and replaced the VLOM. Any ideas?

[Jsdirt]

Did you check oil pressure prior to starting the work? Did you replace the plastic lifter guide trays? Did you replace the seal for the VLOM?

 

This is why I refuse work on these engines - I'll happily drop a crate engine in, but the hell with opening an LS up. I'm getting too old and bitter for the frustration. Some of the worst engineering I've ever seen in this thing. The total opposite of the legendary 350.

 

If the oil pressure isn't up to spec, or is leaking from somewhere inside, the whole AFM system will be screwed up, and can and will ruin new lifters. Also there's been many failed NEW lifters (remember NEW means, Never Ever Worked). There are 1,000 little pitfalls that can ruin your day, thanks to GM's "brilliant" engineering here. What a piss-poor system! If the AFM filter underneath the oil sender is plugged, that will cause problems, too. These engines have ZERO tolerance for neglect, also unlike the 350 that just plain worked all the time, even with 2 PSI oil pressure!  There's also been MANY reports of AC Delco oil filters shedding filter media which plugs up everything and wreaks havoc. There's more - it's hard to remember it all! #2 cam bearing walkout is another source of oil pressure bleed off.

 

Before even touching these, you MUST get 2 oil pressure gauges on it. One up top at the oil sender port, and the other down by the oil filter housing. Pressures ideally should match. If both are low, you're done - the engine is scrap. Also check to see if you have oil that looks like a new bass boat paint job (metal flakes).  If pressures are good but don't match, there's crap jamming up the pressure relief valve for the AFM system, either open or closed.

 

Since #4 is an AFM cylinder, you unfortunately are going to have to do this job twice, and inspect EVERYTHING for the cause of failure.

 

After replacing the rear diff and transmission on my crapbox at 97k and 103k respectively, I now have a decel whine coming from the transfer case, and the clunk that started at 2k miles is now louder than ever. I expected the engine to fail first. Who knew the rest of the driveline is even WORSE! Unbelievable. And yet, GM remains in business ...