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Chevy express making strange noise


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dmarsh76
Novice

Jun 6, 2022, 9:59 AM

Post #1 of 4 (875 views)
Chevy express making strange noise Sign In

Chevy Express
2012
4.8L
Automatic Transmission
179000 KM

Ok, I have a noise coming from My Chevy van that’s been driving me nuts for months.

So when I start my engine I normally hear a knocking/popping sound from between the drivers and passenger seat. It happens prob 5/10 seconds after starting the engine if not immediately. It normally happens as soon as I start the engine and also does so at idle and while I’m driving at any speed. There’s normally about a 20 second gap between hearing it and it doesn’t seem to corrospond to any specific gear, speed, or throttle engagement - in other words, it’s completely random.

I’ve taken it to a few garages who have not seen anything that could be causing it and because it happens so randomly, it’s hard for them to hear exactly what I hear driving it for hours at a time.

The sound seems to vary in loudness and get this, sometimes it just doesn’t happen at all when I start the van. If it doesn’t happen when I start the van or a few mins later, it doesn’t reappear until I re-start the engine.

I can’t pin point exactly where’s its coming from but seems to be in the undercarriage somewhere.

If anyone has any similar experiences please a advise as I can’t find anything online similar.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jun 6, 2022, 10:47 AM

Post #2 of 4 (868 views)
Re: Chevy express making strange noise Sign In

I suspect this is coming from behind the dash and will probably respond to changing the mode or temp settings of the AC. It sounds like one of the air door actuators has stripped out the plastic gear inside. Try moving the AC controls around while the noise is present and see if it stops.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



dmarsh76
Novice

Jun 6, 2022, 10:57 AM

Post #3 of 4 (862 views)
Re: Chevy express making strange noise Sign In

I don’t think it’s the AC. It’s coming from beneath the feet between the driver and passenger seat, and definitely sounds more mechanical then the AC.

I tried playing around with the AC settings anyway and made no difference.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jun 6, 2022, 11:01 AM

Post #4 of 4 (856 views)
Re: Chevy express making strange noise Sign In

Sounds are pretty much impossible to diagnose over the Internet



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.







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