1. Home
  2. Mercedes Autos and SUVs
  3. W123 R134 Conversion

W123 R134 Conversion

On the system there is a pressure sensor and a temperature sensor. I am assuming that the pressure sensor is to prevent the compressor from running if the refrigerant level gets too low. The temperature sensor must turn on the fan when the temperature gets too hot to condense the refrigerant. Does any one know what the pressure and temperature needs to be to switch the switches?

Since the condensation temperature is lower on R134 than R12, are there better sensors to use that the original ones?

Thanks

Reply to
Commuter
Loading thread data ...

Correct on both counts. Pressure sensor is fine... don't need other type. The temperature sensor should be switched to the "Red" one... rather than the green one.

Reply to
Tiger

Is there a part number for the red temp sensor?

Reply to
Commuter

Just look at online auto parts catalog... it is physically green or red color.

Reply to
Tiger

Tried that but the only ones that I have found are the brass housings like the original.

Reply to
Commuter

Ahh... I see what you mean... and that one is green.

0048200710

Autohausaz.com

You have to look on a newer car... like 88 560SEL

Reply to
Tiger

I pulled one with the part number given and the threads are bigger and it has an o-ring to seal for pressure. I am sure of this because the hole in the sensor is wet with oil.

Reply to
Commuter

Look up 1984 MB 380SE... they have both part numbers there... green and red one... they all use same thread.

Reply to
Tiger

Thanks for your help Tiger. I think that I will rewire the fan circuit so that it will run any time that the compressor is running. The fan may run at times when it is not needed but I know that I will get the coldest AC possible. The only thing that I am worried about is that with both starting at the same time it will be a large sudden current draw.

Reply to
Commuter

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.