Does anyone know the amount of pressure needed in the ac system to cause this relief valves to leak?

I had my system filled with about 170 lbs of nitrogen and it wouldn't hold. I found that it was leaking at this valve.

Thanks,

pete

Attached Thumbnails

   

170PSI is way less than the compressor will see during normal operation on a hot day.

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]

I found this same information on a number of web pages. I am not well versed in the workings of the ac unit, but according to what I read, they say that if the valve has been activated, it may not seal properly and will continue to leak. Good luck!!!



The pressure reilef valve is designed to pop at around 450psi (some a little higher, some lower) but "most" do not reseat themselves, and should be changed. many do reseat, but once blown I would not trust it..

__________________
96 E300d

Thanks for the info. I didn't think 170 would cause it to leak. Glad to know I can go much higher next time.

I like to put around 150-200psi of nitrogen in the system before pulling a vacuum and charging. If it holds for 1 hour, I know everything is tight.

I will remove a relief valve from another junk compressor.

pete