jwratts

I have a 1998 E430 with 100,000 + miles on the speedo. There is a vacaum control valve located on the right (standing in front of the car with the hood open looking into the engine compartment) side behind the windshield washer tank. It has developed a chatter but every thing seems to be normal. Does anyone know what this valve does and why would it suddendly develop a chatter.

RichardM98

I think you are referring to the MOT valve. It is a solenoid valve which regulates gasoline flow back to the tank. It can make a ticking sound when operating. Mine is quite quiet but some people have posted being able to hear in while in the car. Don't know if that's a sign of pending failure or not.

FYI - when describing the location on a vehicle things are generally described in relationship to the driver sitting behind the steering wheel. So the MOT valve is on the left side regardless of where you stand outside the car.

ohlord

develop anything.
You suddenly noticed that something that operates normally became something that you suddenly took notice of
It is labaled MOT it is the purge valve a big part of the emissions system and it ticks away at start up and as needed to suck fuel vapors from the tank and CC canister and deposit them safely in the intake instead of into the atmosphere
If you hear it running that is what it is supposed to do. If it is not running it has done its job and shut off on command.
If it had a problem you would have a check engine light and you would then ask what suddenly happened and we would fix it
get some sleep

jwratts

thanks for the info. had never noticed the valve before, probably because the engine isn't running when i am under the hood.

ejsheltra

[QUOTE=jwratts the engine isn't running when i am under the hood.[/QUOTE]

That would hurt!!