Help Diagnosing - Worried about AFM/DOD Failure
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4th Gear
Joined: Aug 2023
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From: Phoenix, AZ
Help Diagnosing - Worried about AFM/DOD Failure
Just purchased a used 2017 C7 base stingray M7. Purchased the car with ~6,500 miles on it. At around 8,000 miles on cold start I heard a louder taping/knocking sound on cold start which would go away within a minute or 2. Car drives great. No CEL. No performance lag. After about 900 more miles the same noise happened 2 more times and I just dropped it off to Chevy.
From reading the forums here this noise does not sound like the videos I have come across and so I’m posting up this video for help identifying what this might be. No warranty on the car as it’s 6 years old at this point so if it is the dreaded AFM issue I don’t know what to do.
Does this sound like an early AFM lifter failure to you?
If yes, and GM can’t replicate the noise what should I do?
In my video you can hear the noise I’m hearing clearly at the 6 second mark (1 knock in the first 3 seconds and 2 pronounced taps/knocks back to back at 5-6 seconds)
Any help or insight is appreciated.
***update 8/24/23: GM techs could not replicate noise. Taking it to Cordes to diagnose before they do some work (LT headers, flex fuel, & tune)***
From reading the forums here this noise does not sound like the videos I have come across and so I’m posting up this video for help identifying what this might be. No warranty on the car as it’s 6 years old at this point so if it is the dreaded AFM issue I don’t know what to do.
Does this sound like an early AFM lifter failure to you?
If yes, and GM can’t replicate the noise what should I do?
In my video you can hear the noise I’m hearing clearly at the 6 second mark (1 knock in the first 3 seconds and 2 pronounced taps/knocks back to back at 5-6 seconds)
Any help or insight is appreciated.
***update 8/24/23: GM techs could not replicate noise. Taking it to Cordes to diagnose before they do some work (LT headers, flex fuel, & tune)***
Last edited by BasedC7; Aug 24, 2023 at 05:49 PM.
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I heard it but it doesn’t sound like any lifter issue I ever heard. Hopefully service will find something simple.
