Sign up for FREE! Become a GM-Trucks.com Member Today!
In 20 seconds you can become part of the worlds largest and oldest community discussing General Motors, Chevrolet and GMC branded pickups, crossovers, and SUVs. From buying research to owner support, join 1.5 MILLION GM Truck Enthusiasts every month who use GM-Trucks.com as a daily part of their ownership experience.
By Brad Davies
I got a 2015 Silverado 5.3l. 138,250km. started ticking sometime last winter. Would happen instantly at start up and last about 5 minutes then would fade away. Sounded like a lifter. Took it to the dealer they said they couldn't hear it. Sound went away so left it.
Fast forward to this winter and as Soon as the weather started to cool down I noticed the ticking again.
Took it back to the dealer said they couldn't hear it again. I went and picked up my truck right at closing, soon as I fired her up the sound was there but everyone was gone so no one to hear it. I took a video. Next day I called the dealer, sent the video. Took like a week to get back to me. In the meantime I had taken videos pretty much every time I started it.
Long story short after a brief fight with them about them trying to say it's normal etc they agreed that it sounded like a noise coming from the valve train. Left my truck with them, they called me said they had to change all lifters. Went to pick up my truck and on start up the sound is still there.
This was a month ago. Sent more videos and a previous video from before they did the work and they are saying they can't hear it again.
Took it in in person they agreed that there's an issue again and they will look at it. Now they are saying it's possible bad injector noise but they can't figure out which one 🙄.
In the meantime I took it to another dealership they changed the vacuum pump. After that the sound changed. Now it's no longer at start up but once the truck has reached operating temperature and is more of a dull sound. Took it back to that same dealer who did the vacuum pump and they said valve train noise and deffo not injectors. But they won't work on it because the other dealer already did.
They didn't change the VLOM or the cam. I had/have no check engine lights. Truck runs awesome. Sometimes rough idle.
Any ideas what it could be?
I have a 2012 GMC Sierra with 5.3 Vortec. I had to replace one head due to damaged exhaust valve. Completed the work and truck is running but on reduced power. Code reader shows 3425-3441-3401-3449 which are the solenoid deactivation codes for the 4 AFM cylinders. I assume I have done something or missed something that is causing this to all 4 of these cylinders. Any suggestions on what steps to take to resolve? Visual inspection of wiring and vacuum hoses has found nothing. Oil was change with Mobil 1 and new filter. Possoibly in limp mode but these are only codes showing.
By Jonathan Floyd
Has anyone ever got a custom tune to delete the AFM on their truck? I contacted my dealership about it and they gave me a local tuners number. I understand that it could possibly void my warranty if deleting the AFM causes a problem. But has anyone deleted their AFM and had issues? As well what cost should I expect to see to have a tuner delete the AFM.
Beating a dead horse here...
Have a Denali 6.2 that I just purchased from CarMax (with an extended warranty/Thank God!)
Tapping sound from the start.
Ran two tanks of 91 octane to eliminate possible octane knock.
Took me past the 7 day return policy and 30 day standard warranty with CarMax. Didn't really bother me because of the factory warranty.
Truck looked brand new. Even had the wrapping on the DVD player.
Popped the hood and started looking for an exhaust leak. I found a donut/flange laying on the crossmember.
Took it to the dealership. Found that the truck had two new fuel injectors and a new Catalytic Converter. Someone was searching for the cause of the sound.
Dealership tightened some gaskets and said the truck was good to go.
It made the deafening tapping noise on the way home.
I returned the truck to the dealership. Even though I have purchased 4 vehicles from them in the past to include a current 2019 Arcadia -- they had no loaner for me.
They kept the vehicle for two more days. Could not find the cause of the noise.
I went back to speak with the service manager. He was not happy.
He went on a ride with me and heard the noise. Claimed it was the transmission searching for the proper gear.
Weird because the noise happens constantly -- to include start up and idle.
Told me his 6.2 made same noises and it was normal.
Finally took it back to CarMax. They sent it back to same dealer with a promise to pay for diagnostics.
Miraculously, dealer finds lifters to be the issue.
I'll keep updated on status of cam, etc.
I think I'll trade this lemon in on a diesel or anything without AFM.
Will also not be purchasing from Bob Howard GMC in Oklahoma City.
Recently Browsing 0 members
No registered users viewing this page.
Most OnlineNewest Member
Who's Online 102 Members, 1 Anonymous, 2,778 Guests (See full list)
- Jamie Davis
- Mike Barber
- Thomas Hanson
- Jason Lund
- Scott Mclay
- jay webb
- Jason Dunaway
- Asd A
- Steve e
- Crazy Schooner
- Jeff Price
- Cool J
- Kevin Grogan
- Marcel Almeida