# 01 740i - Mystery sensor attached to oil filter



## xymox (Mar 9, 2010)

Hi, was checking under my hood the other day and I noticed a little sensor with a hose attached was making a fast clicking sound and I dont know if its normal or not. Im not even sure what the sensor is for but I'll try to describe it. Its attached via a bracket to the oil filter and is squarish looking and is pressed on from a top down configuration. There is an attached (could be a pump) devise on its underside with a hose (3/8" maybe) that runs to the front of the engine. What is this and is it normal to make a fast clicking noise?

Appreciate any responses.

btw, its a 2001 740i sport


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## M.Wong (Jan 9, 2003)

(Photo by cyberdactly)

This, the fuel tank breather valve? Clicking is normal.
Possible P/N: 13-90-1-433-603, maybe 13-90-7-830-766 on the M5.









(Photo by J Irwan)


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## xymox (Mar 9, 2010)

Thanks for the quick reply. as long as the clicking is normal, I guess Im good to go. 
Fuel Tank Breather valve? Seems odd to have some mechanical valve attached to the fuel tank. Is this just to compensate for any vacuum in the tank?


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## drivinfaster (Nov 24, 2007)

believe it is an emission component in the evap system. 


df


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