[cameron66]

I am getting a slight knocking from my 1.8vvt engine which is clearly audible inside the car, especially so on tickover. I believe I have narrowed it down to this solenoid which is located just to the back of the top rocker cover looking from the front. I'm assuming its some sort of solenoid valve assy.

Looks like it may have some plastic fuel pipes attached to it. It seems to operate in rhythm with the engine speed, ie. knocking from it gets faster as engine speed up, but noise quite noticable at tickover speed and seems to resonate back into cabin.

You can physically feel the vibration from it when a hand is placed on it, can get quite loud, and the dealer has ordered a replacement.

I just wondered exactly what it was?, what's it do?

Any idea's

[2.0 vectra]

could be wrong , but that may well be a purge valve for the charcoal canister .

[jackrs]

Its the EVAP contol solenoid (fuel tank vent valve)

[cameron66]

Should it be operating continually. ? ie. Knock,knock,knock about 100 times a minute. IOW are these normally quite audible (continual loud clicking)?

[jackrs]

Yes they do click. Some valves maybe louder than others so see if the new one will fix it.

[cameron66]

Thanks matey. Yes, I've done a google search on them and quite a few people have posted about the noise they can make.

Seems some manufacturers have introduced rubber mounts for them to help with reducing the clicking noises, though in my case its more like a dull knocking noise.
AYS... will see what the replacement one sounds like, hopefully it should resolve it.:) Otherwise I shall be wrapping it in some sound deadening material.:D