Condensation leak in front of AC Evaporator

[protusile]

Condensation is occurring on the AC line leading into the evaporator. The condensation occurs on the tubing right next to the cabin air filter. As the condensation builds up, it drips down into the cabin air filter removal door and soaks the cabin air filter. Eventually, it drips onto the passenger side floor mat.

Any ideas on what is causing this? Condensation should occur on the backside of the evaporator (where the fire wall drain is located), not the front side of the evaporator.

An A/C shop recently replaced the evaporator. I’ve taken the van back to the shop several times but they don’t know what to do. Refrigerant charge and line pressure are OK.

The van is a 2002 GC.

[protusile]

After a little more research on A/C systems, I found out that the A/C line that I am saying is leading into the evaporator is actually the suction side of the evaporator. So the freon, in liquid form, passes through the evaporator and becomes a gas while picking up heat from the cabin air. Since the A/C line from the evaporator heading back to the compressor is still condensing water out of the air, that suggest to me that the evaporator has not fully converted freon liquid to a gas. Thus my GC has an A/C system over charged with freon. However the high and low side pressure meet GC requirements. The only thing that comes to mind is that the new evaporator installed in the van did not match the OEM evaporator and the heat load is inconsistent with the A/C system design pressure. So I'm going to let some freon out of the system. Anyone disagree with this approach?

[Spit]

The way you describe the problem it sounds like all the cooling capacity entering the evap isn't being utilized within the Evap and some of it is still cooling down the 'exit' tubing.

If the charge seems to be correct...How about the metering/expansion valve was it replaced when the Evap was changed? This valve is thermostaticly controlled and it is supposed to be able to vary the amount of R134 it sends into the Evap based on the temp it senses, it may be letting too much R134 into the evap and it's still too cold when it exits? They can and do malfunction

The simplest & cheapest fix maybe to insulate the sweating tubing with insulation tape. If you can keep moist air from hitting the cold metal the condensation won't happen.

Spit

[webbch]

There is no such thing as "the charge SEEMS to be correct". It's one of those things that you have to know is right. The ONLY way to know how much is in there is to recover the existing charge and weigh it. With R-134a, even pressures will not tell you if you're "close". Any shop that tells you they can inspect your A/C system (especially R-134a) and verify that the charge level is correct without recovering it first is lying to you.

The process is to measure in the exact charge, and then verify that pressures are "reasonable". You can NOT check pressures to verify that the charge is correct. Charging by pressures CAN be done, but it's a trial and error thing where you're also monitoring vent temperatures at the same time. Oh, and when you do that, you measure how much you put in so you don't ever have to repeat the procedure on that vehicle. Even experienced techs prefer to charge per factory specs when available.

I would tend to agree that your symptoms do point to an overcharged condition. But like I said, you have to recover/recharge in order to verify.

[gused82]

for some reason i suggest to check if the coolant is fine , because you might have a leak in the heather core , it seems that your a/c its fine , try this , run the engine , without the a/c and if the leak is still there is the heather core leaking ,

I used to work in a A/c shop and was a common problem to see.

Good luck !!!

[RogBed]

I have the same issue. In fact, my carpet is turning white under the mat and starting to leak out past the mat, into plain view. It's a powdery "white" type stain that is hard to wipe out, but with a little elbow grease will.