1996 Climate Control "Popping" Noise

[Falsapartenza85]

Hey everyone!

I have a set of twins... 2 1996 E320's- (white and green)

My white E320 has developed a popping, almost hissing, type noise that is intermittent. It comes and goes every 20 seconds or so and is feignt to hear. It comes from the passenger-side front of the car behind the center console and is driving me NUTS! It sounds like a release of pressure, air, or something!!!!! I have isolated it to the Climate Control as the noise does not occurr with the System off. Blower works fine and doesnt make any noise. The pop/hiss noise does not get louder or become more repetitious as you turn up the fan speed... I can't figure it out!!!!

Anyone have a similar experience? My Green 96 is flawless, other than a new spring perch replaced by Mercedes under warranty (but thats for another post )

All thoughts greatly appreciated!
-Michael

W210- 1996 E320/ 102,000 miles/ White with Black Leather
"Adelweiss"
W210- 1996 E320/ 100,000 miles/ Green with Beige Leather
"Frau Gruhn"

[cool]

Your expansion valve (part of the aircon system) is the one making the hizzing sound, this may be due to freon gas leak which then lowers the gas level and possibly you would need to have your aircon system service and repair, like change of drier tank, expansion valve, general cleaning, thats all there is, if the hizing sound persist after the general cleaning, you can ligitimately complain to the supplier of the expansion valve, not all of this part are made with standard quality, there are chances that you will meet up with a defective valve even if its new.