Grand Caravan A/C

2000 Grand Caravan - my battle bus. Driven infrequently. I've owned it maybe 10-11 years and never put refrigerant in it, surprisingly. Lately I've heard a hiss from the right rear quarter, inside. Sure enough the A/C is getting warmer.

It has a separate fan control for the rear seat area, so I can only assume it has a separate cooling coil back there. Is this the case? Is there a common failure point? How do I get to it?

Oh, let me add, interior trim and I don't get along. Thanks.

I had the stealership take care of mine when it failed.

Thanks, but I'm not eager to do that on a 14-year-old car. Paging Vigo to the Mopar courtesy phone, please.

Yes, it has a separate evaporator (cooling coil) in the rear passenger side.

The hissing sound is probably just the refrigerant moving through the thermal expansion valve which is a variable tiny orifice that shoots refrigerant into the evaporator in a mist/atomized state. It is probably just low on refrigerant due to a leak.

The easiest way to do a 'usually good enough' repair is to just buy one of those dinky little setups from walmart that has a can of refrigerant with a fill hose and a tiny gauge attached. The gauge reads 'low side' pressure and you would generally want it to be 35-45 @ 1500 rpm and just keep adding until it gets there.

If you want to be able to actually diagnose the issue i would buy a set of real a/c gauges ($40-60 at cheapest) and an r-134 'can tap' and then you'll actually be able to see pressures on both sides of the system and diagnose stuff, and be able to use the cheaper refrigerant cans without extra stuff in them. Cheaper in the long run if you do multiple cars.

Thanks, man. I've definitely got the cheap low-side kit already. I may still have my father's full set, if it hasn't taken a walk.

Buy a can of 134a with dye, put it in, pop a blacklight CFL in your droplight and look for the glow. Glow in the condensate drip tube typically indicates bad evaporator core.