knocking

[~JT~]

Knocking on 172 cup coming from front right

Hey guys, wondering if anyone has any experience with this concern.... My 172 cup starts to make a subtle knocking after having been sitting idling for about 20seconds:dapprove: . It cant really be heard from outside the car very well, but in the drivers seat it can be. Sounds like its coming from the front right. I believe there is a canister (something to do with emission control) behind the front right fog light? Whats this do?and could it be this making the noise? Price to replace etc? CHeers, any help appreciated. :approve:

 

[davebem]

If you mean the canister that absorbs fuel vapours I think all it has in it is a solenoid valve, if your car is stalling or has a very lumpy idle then this will be faulty.

 

[edde]

As Dave said the carbon canisters are seeming to fail more in the cold and wet. Only cheapish to replace. The value is making the noise.

£40 rings a bell for a new one.