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I hope its okay to start a new thread. I have done a forum search but cannot find any posts with a similar issue but I guess hidden somewhere in the forum there may be.
I have recently purchased a 2017 GS Collector Edition with 10k on the clock. I keep getting this strange noise which you hear in the car more than out. Its a tapping sort of noise but sounds 'soft' so, more of a plasticky tap than a 'hard' metallic tap. It comes and goes. Sometimes it is that prominant that even my Mrs noticed it, other times it goes completely. I have not had it long enough to really put a finger on if it is only when the engine is cold or not.
It seems to go away when the engine is revved but that may be beacause the engine drowns out the noise rather that its actually going. I experimented a little tonight and noted that if I stopped the engine when it was doing it that when I started up again, it was not there but came back after 30 secs or so.
It seems you can hear it more towards the top of the dash and infact, if you put yopur head down in the footwell, you can barely hear it at all. If you lift the hood and look under, you cannot hear it but that may be because the sound of the engine drowns it out.
I have videod it and placed link below. It actually sounds worse in this video that it does in real life!
A little hard to tell in the vid, but does the frequency of the tapping increase with engine RPM? My first thought was an injector, but if it's not RPM dependent it wouldn't be that or any rotating component. can you hear it if you open the hood and get down next to the firewall?
When you increase RPM it goes. I am not sure if that because it actually stops or if the extra revving drowns it out. Same if you go under the hood and listen down by the firewall, you cant hear it but that could be because its drowned out by engine noise.
It seems loud enough that a minor rpm change like say going from idle to idle+500 rpm would let you hear it but is still a large enough that you’d be able to determine if it speeds up/slows down with the engine.
This is the fuel pump pulses which causes a ticking sound. The noise is carried to the dash by the fuel lines. There is a service bulletin with revised fuel line part numbers that eliminates the problem. Not an expensive repair.
It seems loud enough that a minor rpm change like say going from idle to idle+500 rpm would let you hear it but is still a large enough that you’d be able to determine if it speeds up/slows down with the engine.
Is that not the case?
Its really hard to tell, just the faintest touch of the throttle and the noise either goes or is drowned out and I think its the latter.
This is the fuel pump pulses which causes a ticking sound. The noise is carried to the dash by the fuel lines. There is a service bulletin with revised fuel line part numbers that eliminates the problem. Not an expensive repair.
Hmm, interesting possibility. May have a word with our local dealer then. There is only one in the UK!!
This is the fuel pump pulses which causes a ticking sound. The noise is carried to the dash by the fuel lines. There is a service bulletin with revised fuel line part numbers that eliminates the problem. Not an expensive repair.
Just had a quick look round this and other forums on the fuel pump noise and yes, the way people describe it is just like I am getting. Certainly seems like the first thing I need to rule out. Thanks!!
The C6 dry-sump cars had an issue with a Transfer Tube O-Ring Failure inside the oil reservoir. The seal would slip resulting in the tube rattling inside the reservoir. When my C6Z started making the noise it was a slower rattle but the sound came from the same basic area of the dash.
Use an automotive stethoscope (or a short piece of wooden dowel) to listen to the dry-sump reservoir to see if the noise is coming from the reservoir.
The C7 dry-sump is basically the same unit that was used in 2009 and later C6 ZR1, Z06 and GS. Although, GM may have addressed the problem in later production the failure may still occasionally occur. It is at least worth eliminating as a cause of the noise you hear.
This is the fuel pump pulses which causes a ticking sound. The noise is carried to the dash by the fuel lines. There is a service bulletin with revised fuel line part numbers that eliminates the problem. Not an expensive repair.
Really?!?! I didn’t know that was an issue. I have the same issue (at times) as the OP and couldn’t figure out what it was. It rarely does it so I couldn’t figure out what it was. Mine isn’t nearly as loud as the OP but I noticed it.
C7 tapping noise dash area
