Knocking Noise

[tims84]

Hi all,

 

I've got a 2013 Citroen C1 and since day one there has been a knocking noise that comes every time I change gear. I was told this is normal so have learned to put up with this. The issue I have now, however, is that a similar knocking noise occurs whenever I switch the air conditioning on. It only does it as the air con kicks in but doesn't continue while it is on. Any ideas of what it might be?

 

Thanks

[paul.h]

Welcome to the forum.

 

The air con noise, if it is coming from the right hand end of the engine, will be the air con compressor clutch pulling in and is perfectly normal for all cars with air con. If you park the car, lift the bonnet and then switch on the air con with the engine and cabin fan running, you will hear the noise and should be able to notice that it comes from the driver's end of the engine. Also you may notice the noise cuts in and out whilst the air con is running as the compressor starts/stops as part of the air con control system. You should also notice the engine fan will be doing the same or just run continually whilst the air con is on.

 

To help prevent mould build up and the air con becoming smelly, I usually switch off the air con but leave the fan running, about 1 mile from the end of a journey to allow the evaporator matrix (cooling radiator behind the dash) to dry out since it becomes wet with condensation during use. If it does become smelly it can be cleaned - a dealer will do this or you can buy purpose designed sprays but Dettol surface cleaner (non bleach type) finely sprayed in to the cabin air intake with the fan on after removing the pollen filter, then left to dry, works well.

 

I am not sure about the gear change knocking noise being normal though, perhaps you should get the dealer to demonstrate it on another car and if it does not do it then get them to look at your car whilst still under warranty.

[tims84]

Hi Paul,

 

Thanks for your reply and for reassuring me this is normal. As it has only just started happening I thought it may have been an issue. Perhaps I am just noticing it a bit more as I am using the air con more than normal in these cold months to clear the windscreen.

 

With regards to the gear change knocking I took the car in a couple of weeks after buying it and the technicians looked at it and came back to say it is common with all citroen C1 models. As I'm taking it to a different dealer for its next service in a few weeks I may bring it up and ask them to double check there are no issues.

 

Thanks again

 

Tim