Mysterious 'surging' sound
Posted: Mon Jan 14, 2019 5:25 pm
Here's an odd one: once warmed up, my 2010 1.6TDI produces an odd 'surging' sound at idle – it's akin to the sound a fuel pump might make if it's cavitating and, from the driver's seat, it appears to come from the engine bay, or dash area. It's a low-frequency sound that you cannot hear anytime other than at idle and is not a constant sound, but a pulsing. The interesting bit: if you turn the air-conditioning on and then back off again, the sound disappears for a few seconds before gradually returning. Air-con on, sound disappears. Air-con off, sound gradually reappears. If it had been the other way round, I'd have said it was the air-con making the sound and probably in need of a charge or new compressor but as the sound only appears with the a/c off, I'm stumped.
BTW, you can't hear the sound from under the bonnet – mind you, all you can hear is the TDI engine doing its thing anyway. The guys at Celtic Tuning had never heard it before and wondered if it was anything to do with the EGR valve, but who knows. Car has done 32K miles.
Any ideas?
BTW, you can't hear the sound from under the bonnet – mind you, all you can hear is the TDI engine doing its thing anyway. The guys at Celtic Tuning had never heard it before and wondered if it was anything to do with the EGR valve, but who knows. Car has done 32K miles.
Any ideas?