'Tis the season... for my air-con to die- '91 300E
 

Cranked up my air con the other week and just warm air flowed out, so I took my car to my tech and he converted it to R134a and I had lovely cold air. For a day. Next day- warm air again- so another charge, cool air for a day then next day nada. Then I went on honeymoon.
I know bugger-all about air conditioning systems so I presume I have a leak- my tech say he hopes it's not the evaporator which apparently is $$$'s.
Could it be anything to do with the conversion or something fairly easy to fix?

cheers.

anyone?

would a faulty evaporator 'cause the loss of charge just overnight- or does that sound more like a leak somewhere else?

Leak could be from almost anywhere in the system, and it seems like too big a leak to be caused by an o-ring coming out of its groove. I'd have a tech check it out w/ some dye to see where it leaks from.

I've read some more posts and it seems people are split 50/50 about whether converting to R134a buggers up your system.

can you re-charge with R12 after a R134a conversion or is it a no-going back deal?

my tech says the conversion isn't the reason the charge isn't holding, and I usually trust him, but I'm interested in whether the quick conversion he did could be the problem?

Probably not. Most conversions involve draining/flushing and finally vacuuming the AC system (which may take a few hours depending on the person), changing the service port fittings, replacing any worn hoses/o-rings/etc., adding new oil to the compressor and refilling w/ r134a. Basically a day's work at the most.

If anything, switching to 134 just exacerbated whatever leaks you already had w/ the r12.