W124 Evaporator Replacement - Some questions
 

The evaporator in my 93 300E is leaking, and I'm getting ready to do the replacement. I've spent the requiste time reading up on the procedure in the tech manual and this forum, but I've still got a couple questions:

1) I'll obviously need to evacuate the r134a before doing the replacement, but should I completely flush the system? I'm worried about the amount of oil... some oil has probably leaked, and it seems flushing is the only way to gaurantee that I have the factory spec qty in there.

2) What oil does this car use? I understand its PAG, but it comes in three weights - 46, 100 and 150.

3) Several people have said its a good idea to replace the 'vacuum elements' when doing the evap replacement. What are these, and how much longer does it take to do this as well? Can anybody give me a part number (numbers?) for what I need to buy...?

4) The MB Tech manual says to apply 'sealant' to the sealing surface of the a/c box (step 18 on procedure 83-554). What sort of sealant should be used here?

5) Anything else I should replace/worry about while I'm in there (seals, etc.)? I really don't want to have to open this thing up again in three months when something else goes wrong....

Wish me luck...

Dordal,
 

I am a DIY'er and I replaced my evaporator myself. However, I took the car to a professional with the right equipment for evacuation and convertion to r134. By the way, I don;t think you have r134 in your car. I think you may still have R12. Check the labels in your engine bay.
The vacuum elements control the opening and closing of the flaps to direct air condition flow within the cabin. Once you remove the dash, they will be seen at plain view. Easy to replace. You can buy the whole thing or just the rubber portion, which goes bad after a while. Do a search, it has been discussed recently.
As far as the sealant once you open the "box" you will figure it out. It is just a regular foam seal similar to what you use for a window ac.
I wish you luck!:cool:

I'd replaced the 2 recirc elements and the one inside the case at the same time. Other than that, if your going to run 134, replace the expansion valve with a 134 valve. Dont sweat the oil, run ester100, add about 2 oz to the evap and 2 to the dryer.

Otherwise, its pretty straighup, just keep those fasteners organzied. :-)


Joe

Joe P, 1993 300E's came stock from the factory with R134a.

Thank goodness, this seems to be the first year they were using 134a. Definitely makes life much cheaper.

suginami, do you know what refrigarant oil they used? I'm now thinking I may not do this work till next spring, but if I don't I should probably add a little more oil.

No, I don't, but I'm sure LarryBible does. Try e-mailing him.

Actually the question of r134a has come up before, and it was determined that 400E's and 500E's got r134a starting from 1992, and the rest of the models got it in 1993.

Thnaks for the clarification. Just thought I'd follow up for the record: I asked about the oil on the Air Conditioning board (www.aircondition.com) and it looks like its PAG 46.

FWIW, my 92 400E has R12, so not all 92 300E's have R134. Also, looked at a 92 300D that had R134 factory sticker the other day.