I noticed about 3-4 months ago when checking pressures, that after I disconnected my gauges, the valve stem was hissing on the high side. I tried pressing it in thinking maybe some dirt was clogging, but no luck.

Yesterday I got out of the car and heard heavy hissing -- well looks like the high side valve cap blew a hole through it and now my refridgerant is low.

Any ideas on process I should take to try and repair without having to evac or do I not have any options other than evacuation?

And IF I do evacuate, would you recommend I replace R/D for preventative maintenance? I'm not even sure if it was replaced when the car was converted from R12 to R134a. One day when I rebuild system (evap/compressor), I'll backconvert, but I'll keep it simple for right now.

A side note too -- I was seeing over 300psi on high side during hot days (110F)...I was recommended to "soak" condenser coil -- how can I soak it exactly? Or is the cleaner some sort of foam?

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k