loud ticking from evap purge solenoid.

[Chalpkin]

Hi all,
My 2001 C320 petrol has developed a loud tapping/ticking noise that from inside the car sounds like a tappet but on closer inspection it turns out the noise is coming from an electrical component sited on the front right hand side inner wing which according to my Haynes manual (American version), is called the Evap canister purge solenoid, for some reason the noise under the bonnet is not as severe as it sounds from inside the car. the noise is certainly coming from this unit as you can feel it through your fingers.
Is this a sign the solenoid is on the way out or can I leave it alone, the noise is annoying but if its not doing any damage why replace it
Regards,
N.Chalpkin.

 

[grober]

AFAIK its controlled from the engine ECU which takes into account the engine temperature and inlet manifold vacuum/throttle plate position among other things. The valve or its associated pipework [especially the rubber connectors which crack] may be faulty or it may be a symptom something else is wrong. If you check the pipework and replace the valve that may well cure it. If not you will have delve deeper.