Today i changed airfilter from stock to K&N it was freaking hard and way too many screws to unscrew. Anyway, after i changed it and put evertying back together, i've noticed that clicking noise that i never heard before. I have some clicking noise near radiator, i was told that its coming from tensioner(t-belt, fan belt, water pump, and something else replaced 2 weeks ago) so it was ok. but since i replaced that filter i noticed clicking noise near firewall kind of behind the engine. Does anybody know whatit could be?

 

y was it hard to change the filter? it should have been hard. can u be more descriptive or the noise? i kno it's hard to describe noise but it's also hard to tell u wuts wrong

 

i never changed airfilter on audi b4, so when i found out that i had to unscrew heatshield, then some black metal pipe that screw to air box, unplug hoses, unscrew airways, and after 30 minutes of unscrewing things you have to dodge all these hoses and wires to pull that enormas airbox. compare to some eclipse its kinda hard
THE NOISE: sounds like clicking, not very fast and constant even when i rev the engine, when u look at the engine from bumper side its on the left but behind the engine(near firewall)
I thought it might be some kinda pump but its too loud.

 

bump

 

It may be the gas evap valve that sits at the back of the airbox. It should make a soft clicking sound.