Hello everyone, I have a '95 E420 and I was told that my A/C evaporator have gone bad. My questions is that, is the a/c evaporator hard to get to? would it be hard for someone to do it themselfs? and what else should I look for before i know it is indeed the evaporator that has gone bad, and last if I was to replace the evaporator what else should I replace when I have all that **** apart? and I'm not being sarcastic. please help!

 

I am sorry to say that my understanding is that replacing the evaporator is one of the worst fixes for our cars. Some say that you have to dismantle the entire dash to get to the evaporator, although I did see a pictorial of doing it from the engine area. They detailed a way to dig down under the windshield wiper system. I like the idea of leaving the dash alone, because I have always worried that things would get broken during the process and that I would end up with all kinds of new rattles and squeaks inside the cabin.

I thought my evaporator was bad a couple of years ago, but I was lucky and it was just leaking at the expansion valve and the receiver dryer. It wasn't cheap to fix, but it was much less than I was quoted for the evaporator. I should add that the first shop couldn't find the leak, but the dealer found the problem quickly. I would just try to be very sure it really is the evaporator, before I signed up for the repair.

They told me that you should be able to see the fluorescent dye at the weep holes under the car, if the evaporator leaks. They also told me that if it is a slow leak, then it might take multiple dye injections to allow enough dye to escape and leave a trail.

I was going to replace the fan motor, if they had to pull the dash, because they are prone to squeaking as the motor bearings age. Mine squeaks occasionally, but right now it is quiet. I think they also typically replace the charcoal filter and the receiver dryer, whenever they fix major things on the AC system.

If you have to replace the evaporator, then try to look on the bright side. If you do the worst fix there is, then it should be all rosy from now on. For example, if I do the evaporator, the head gasket, and the wiring harness, then my car should be fine for 500K miles. That isn't such a big price to pay, unless you just purchased the car and you hadn't intended to put any money into fixing it up.

 

Evaporator is under the wiper arm assembly behind the firewall. I had to remove the wiperarm assembly on my 190E to get to the evaporator tray and clear out the drain holes. It wasn't easy but once I had everything apart, I could see the evaporator pretty clearly. That was a while ago though and a W201 is by no means the same as a W124. The problem with doing it yourself is you are constanlty leaning over the fender trying to reach into just about the absolute center of the car with lots of things in your way. Unless you work in the HVAC industry, I would let someone else do the job. Make sure they clean out the evaporator tray while they are in there. If you live in a warm climate, all kinds of trash builds up in there and if the drain holes clog, water condensation will start dripping into your footwell everytime you turn on the A/C.

 

Before you do all this work you might want to try a can of stop leak for the a/c. It is about $6 and takes 5 minutes to put it in. A friend with a 124 was given an estimate of $2,200 to replace his and it leaked down in a day or two. We put one can in and that was last summer and it still works fine. You can get the stop leak at any auto parts store.

 

Yes it is a big job but you CAN do it if you are reasonably mechanical. It will take a couple of days and the only way to do it is to remove the whole dash. Just mark all the air lines as you remove them from the heater box.