Putting R134a Refrigerant In A 1991 W126 350SDL--Use A Different Expansion Valve? - Page 4 - PeachParts Mercedes-Benz Forum

Demothen · #46 08-08-2016, 09:00 AM

Insulation over the txv? I was not aware of that. Anyone have a part number for a w123?

Edit: just read the FSM again and noticed it mentions opening the insulation. Did a bit of research and it seems like I could just wrap it with some foam tape if necessary, but it would be nice if I had the correct part.

Squiggle Dog · #47 08-08-2016, 04:14 PM

I looked at the different types of expansion valves in the link. Thanks.

The W126 350SDL uses an expansion valve insulation housing 126 835 06 40. You have to order two as one goes on each side. They are usually available for under $5 each.

Zulfiqar · #48 08-08-2016, 04:19 PM

Quote:

Originally Posted by Demothen

Insulation over the txv? I was not aware of that. Anyone have a part number for a w123?

Edit: just read the FSM again and noticed it mentions opening the insulation. Did a bit of research and it seems like I could just wrap it with some foam tape if necessary, but it would be nice if I had the correct part.

you can either buy the foam pieces from benz or get a roll of presstite tar tape, both do the same job.

The insulation is to prevent the thing from sweating and making your interior wet.

Zulfiqar · #49 08-08-2016, 04:22 PM

Quote:

Originally Posted by leathermang

My impression is that it is a ' reference' temperature 'gauge' or reference pressure based on temperature .... the longer tube in the system should be in contact with part of the evaporator I think.... OR.. is that TXvalve situated so close that THAT could be the sensing tube in contact with the evaporator ?

Tech Tips for Thermostatic Expansion Valves

Thermostatic Expansion Valve

You are writing for a T shaped expansion valve with the sensing capillary tube, Which you are 100% correct for.

This one is an H block. and the sensing tube passes through the suction port in it. This one is actually showing a little tail of the same capilary sticking out - I think its used for something on the production line - some dont even have it anymore - all you see is a flat rivet.

Demothen · #50 08-09-2016, 10:51 AM

Quote:

Originally Posted by Squiggle Dog

I looked at the different types of expansion valves in the link. Thanks.

The W126 350SDL uses an expansion valve insulation housing 126 835 06 40. You have to order two as one goes on each side. They are usually available for under $5 each.

Thanks. How are those pieces supposed to be held together? They're cheap enough that I might as well buy the right part and not worry about trying to get tape wrapped around them.