The hose you see going to the fan motor is just to help cool the brushes. That's not related to the problem.
This is common on any brand and model car. The drain tube is blocked. The AC system is only expected to cool the car about 20 degrees. The comfort comes from removing the humidity in the air. The AC will also run in the winter when you turn on the defroster. It does this to remove the moisture before heating the air and blowing it onto the windshield where the moisture would condense and cause fogging. The moisture that is removed drips into a drain pan and flows onto the ground. When the drain tube is blocked, water builds up in the drain pan until it overflows, usually when going around a corner.
Look under the hood, on the passenger side of the firewall, for a gray rubber tube about four inches long and with a right angle bend molded in. Squeeze the end of the tube to open it up. If water doesn't come pouring out, the tube can be removed by squeezing the spring-metal clip around it. Pull it off to check for an obstruction. If the hose is clear, carefully stick a pencil into the plastic tube on the firewall to dislodge the leaves, lint, dirt, mouse nest, ... Whatever is in there, then stick the tube back on.
The retrofit did not cause this problem. Most cars are not retrofitted to the new R-134 until the system stops working or is working poorly. When it was low on charge, very little condensation would have been removed so the plugged drain would likely have gone unnoticed. Now that it's cooling properly, more moisture is filling the drain pan faster than it can evaporate. The same thing would have happened if you had just recharged the system with the old R-12.
Most systems work just fine with R-134 because there was so much extra cooling capacity built into them. That's why they need an expansion valve to slow down the flow of refrigerant. The evaporator in the dash must not be allowed to go below 32 degrees or the condensation will freeze and block air flow. It's true that R-134 is less efficient at removing heat unless system pressures are beefed up. That would require a different compressor, which we typically don't need to replace. Since there is so much extra capacity in the system already, the expansion valve just allows more of the less efficient R-134 in to achieve the same result. I did this retrofit on my '88 Grand Caravan many years ago and it worked great.
Sunday, January 10th, 2010 AT 1:05 AM