Hello Bricksters,

I have a 1995 960 sedan whose A/C has been less than phenomenal. Every summer for the last couple of years we have had to recharge the A/C in order for it to blow cold air. The dealership has checked for leaks and found none. Anyway, can anybody out there offer any suggestions for isolating the problem?

Thanks!

Evaporators are notorious leakers and often difficult to detect. With a UV dye you might see some floresence where the Evap box normally drains. Organic debris (leaves, seed pods, etc.) can get in through the fresh air intake then get wedged in the fins of the evap. Moisture pulled out of the atmosphere condenses with the a/c on and these can swell up putting strain on the evaporator itself. When the freon and oil leak out, the oil (the carrying agent for the dye) gets trapped in this same debris and can cause the dye to never reach a visible place.

If they've checked all the obvious places and come up empty, the evap is usually where most techs will place suspicion, however, since this can be a much more labor intensive repair than a hose or o-ring. Might ask if the service facility has a 'sniffer' to check for a leak in the airbox.

Of course, much nicer to be servicing the a/c often on an R-134a system, sure wouldn't want to be in the same boat with R-12.

On my '93 960 the evaporator had sprung a leak. It wasn't a bad job to replace. I doubt it took more than an hour or so.

That should be an easy answer; find where the leak is coming from and fix it.

However, some leaks, especially small ones, are virtually undectable. Also, the more you pressurize the system, the more it leaks out in some cases. Therefore, if you run the defrost frequently even in winter months, it might fizz out of an unseen hole. Possibilities are endless. Dye and a leak finder are the best ways to go. Don't get upended about it until they tell you where the leak is. Then you can decide whether to recharge or just to fix the problem. Often leaks are not terribly expensive to fix, although the possibility exists.
--
Chris Herbst
1992 745, 68k

And others:
93 944, 150k
90 245, 110k
88 744, 160k
87 245, 185k

Chris:
I have a side Volvo question and can't sign into Brickboard because of some cookie problem. Please email me at sringlee@hotmail.com so I can ask it.

Evaporators go in these cars. Easiest way to detect way an evaporator leak probably is putting an electronic leak detector against the evaporator water drainage hole in the firewall below the accumulator.

Refrigerant can only leak in several places...any seal/connection, any rubber hose, or any pinhole in the condenser or evaporator or other metal interface.
Sounds simple, but the leak rate can be quite small if it's not large (well, duh!) and easy to detect. It doesn't help that R134A leaks more easily than the old R12. It's the small leaks that separate the technicians from the parts changers.

OTOH, a small leak should be findable if it's not masked by some gross leak, which you imply you don't have.

Ensure the shop you take the car to has an electronic leak detector, not the old style propane burner freon detector. Also, you might consider injecting a dye-type detector into the system and waiting a few weeks to see where the dye collects...I prefer a UV-flourescent dye.

You might find the stuff is leaking right through the rubber hose but more often it's a pinhole (rocks hit condensers!) somewhere. Compressor seals are another good source of leaks.

On my '96, the compressor started to bind up and broke the clutch links because the system's oil quantity was too low. Apparently it had several recharges of freon but the oil was never measured and replentished. Depending on where the leak is you will probably loose oil as well as freon. (I never noticed any leakage of oil but it was missing when I took the system apart to replace the compressor and dryer.)
--
'96 965 at 89K. Had '85 745 Turbo Diesel for 200K.