2005 Toyota Sienna Rear Evaporator Leak

sk8tingusmc · Posted at Mon Oct 19, 2009 4:36 pm

Air Conditioning problem
2005 Toyota Sienna 6 cyl Two Wheel Drive Automatic 81000 miles

I have a rear air evaporator that leaks water into the inside carpet of the cargo area in rear of van. I have had it checked by toyota technicians and they can not figure it out. When the air is on water squeezes out the inside of the evaporator around the pipe and soaks the foam surrounding it. Then water drips directly into carpet below.

pear69 · Posted at Tue Oct 20, 2009 6:19 pm

Is the A/C system fully charged with the proper refrigerent?

sk8tingusmc · Posted at Wed Oct 21, 2009 5:50 am

yes it does have proper refrigerant. Everything about it works great, but it leaks water out the back evaporator. The toyota mechanics have no clue, but they think it is the expansion valve.

pear69 · Posted at Wed Oct 21, 2009 9:58 pm

First, you must understand this, your evaporator is not leaking water. That is impossible! (it may leak refrigerant) but not water......
Evaorators, in an automotive A/C system, "evaporate heat" from inside the cabin, to the outside atmosphere. They do this by circulating refrigerant through the A/C system (which includes the evaporator). This refrigerant absorbes "heat" and releases it to the outside atmosphere....
Your issue, is the condensation that is a result of airconditioning.
There are many factors that can cause excessive condensation to build up on the evaporater. The most common is the level of the refrigerant.

How much refrigerant is in thre system?

avenue723 · Posted at Wed Oct 21, 2009 11:02 pm

EVERY A/C system has an evaporator- AND IT CONDENSATES which results in water dripping- THERE must be a water route for the evaporator- either a little hose, or a runway, something. Every car usually has a hose to let the water drip down to the ground. try looking for a runway or a hose-
every car that has a/c drips water
- try making a shield or something to direct water away.

sk8tingusmc · Posted at Thu Oct 22, 2009 3:20 am

Sounds like a great idea. I actually came up with it myself yesterday. Thanks for the suggestion.

pear69 · Posted at Thu Oct 22, 2009 8:57 pm

Every A/C system indeed has an evaporator, and the condensation must be drained out somehow; but A/C systems in cars are not new, and I am sure that the Toyota mechanics that you mentioned, checked out the drain system. If they didn't then they are not Toyota mechanics. You also mentioned that the mechanics think that it is the expansion valve. The expansion valve meters the amount of refrigerant that is allowed into the evaporator. If too much is allowed to go in, the evaporator will create too much condensation, which will - in turn - cause the drain to be overwhelmed with water...Re-engineering a new drain will not fix the problem.