PeachParts Mercedes-Benz Forum - View Single Post - At Least the Evaporator is Apparantly not Leaking

Greg in Oz · #20 07-08-2004, 04:22 AM

Larry,

Have you considered as to whether or not the repair is essential? You are probably like me and cannot stand the thought of something not working as it should. In a situation like this though, I would be asking myself if I could live with the problem (if no damage will occur) until there was a greater need to pull the dash apart (eg. evaporator failure). If it simply means that the air-con will not be quite as cold as it should, then I think I could live with it for a while.

I realise that your 124s got the pushbutton full auto climate control whereas ours got what I refer to as the "manual" climate control with dual temperature thumbwheels and rotary controls for air direction and air volume/fan speed. I therefore don't know how much is common between the two systems. I have mentioned here previously how we don't seem to get as many problems with ours with the lack of the pushbutton unit and associated electronics and our 124 evaporators don't seem to have the same reputation as yours. One obvious difference is that ours have separate left and right heater cores and where you have a mono-valve we have a dual version (a duo-valve?).

I'm fairly sure with ours, air volume and direction are controlled directly by the person moving the controls, so we presumably do not have the vacuum actuators/pods associated with these functions. We do still have a recirculation pushbutton and therefore at least one vacuum pod (maybe the same two as yours) for this function. I don't know if we have several stages of fresh vs recirculated air as mentioned by Jim Y, but I do know that a few minutes after starting the air-con on a hot day with a high fan speed selected, there is an audible change in the air path (not air speed as remember our fan speed control is manual). This suggests to me a change over of fresh vs recirculated air and that there is still some degree of automation in our "manual" system. My understanding was that normally, fresh air was used unless the recirc button was lit (this function self cancels after a period of time to prevent build up of stale air/CO2).

I'm probably getting off the track here with all my waffle, but the point I'm getting around to is that, to the best of my knowledge, our system uses refrigerated fresh air most of the time and copes with our Aussie climate in summer just fine (often around 40 degrees C). That is even in our '90 300TE which has 134a retrofit and the greater internal volume of the wagon to cool (although being a wagon, it has the larger version of the Nippondenso compressor). In the six years we have owned it I have had refrigerant added once. If ours works in our climate with refrigerated fresh air and that is the "failed mode" of yours, can you live with it in your climate?

I once had to make a similar decision with my '73 350SLC. One of the air direction flaps on the driver's side jammed preventing me turning off the heat on that side. I was faced with the choice of pulling the dash apart to fix it properly or simply disconnecting the linkage to that flap from under the dash which could be accessed fairly easily. The latter option (which I chose) simply means that when the heater is switched on for either the driver's or passenger's side of the car, the driver's side gets heat. There is also less progressive control of the heat on the driver's side. At the time I figured I could live with that fault until I had to pull the dash apart for something major. As it turns out, that was about 18 years ago! Nothing major has necessitated removal of the whole dash yet.

Again I ask, can you live with it until something really requiring removal of the dash such as the evaporator occurs? Not that I would wish something like that on you.

Greg