On a '96 S420, what is... - Benzworld.org

ninjamonkey · 05-29-2004, 11:27 PM

...that cylinder hanging by foam pads just next to (towards the rear) of the mono-valve? It seems to have a vacuum line connected to it. Every now and then, while working under the hood, I noticed that it "clicks" continuously and rather noticably, like a broken relay. I'm thinking a some sort of pressure monitor/switch?

guydewdney · 05-30-2004, 01:21 PM

pic?

had a look on the epc - looks like it might be a control valve for the vents auto open / close...

BENZDOC · 05-30-2004, 09:02 PM

Sounds like the purge valve for tank ventilation.

ninjamonkey · 05-31-2004, 03:23 PM

Purge valve? Is it supposed to click like that?

This is a view from the front driver's side -- this is under the front plastic shroud:

guydewdney · 05-31-2004, 03:55 PM

does it click only with engine running?

does it click with air con off (ec light on?)

does it still click with all ventelation off?

can you get a part number off it?

had a look - def not the vacuum system

not heating ventelation as far as i can see.

could be (as mentioned above) fuel thingy - so:-
140 470 00 93
000 470 20 93
000 470 15 93
are all the same part (the first was replacedc by 2nd which in turn replaced by 3rd... - obv cocked up design....)

BENZDOC · 05-31-2004, 08:41 PM

Quote:

ninjamonkey - 5/31/2004 5:23 PM

Purge valve? Is it supposed to click like that?

This is a view from the front driver's side -- this is under the front plastic shroud:

yes it clicks when the engine reaches operating temp. Thats why it's mounted in rubber mounts. It gives the tank pulsed vacuum instead of continuous. Tampering will trigger the check engine light and store codes.