108 AC Issues, possible stuck expansion valve?

[Bezant]

Hi guys,

I have the a6/thermoking system.

I had my a.c. Charged and it worked great for a while but had leaks at the drier and rear of the compressor. Replaced both, oiled, vacuumed, and charged it and the compressor was pulling a vacuum on the low side with no cooling happening.

We suspect stuck txv. Is this the most likely? It seems nla everywhere, 108 835 03 72. I was also told it might just be swappable since it was a generic American ac system.

Also and guidance on accessing, I've seen posts where the evap is bolted below the glove box insert and others saying it's inside the front fender. Can anyone shed some light.

[97 SL320]

When you get high pressure on the high side and low / vacuum on the low side, that points to the expansion valve being stuck shut.

Have a look through a 4Seasons brand AC catalog / buyers guide.

[Ziad]

Pretty sure I have a NOS one for you. Send me a email and I will forward pictures.

[Idle]

What year model are we talking about? The early 108s, from 1967, had Thermoking units with the evap sort of built into the area behind the dashboard with the fan right next to it.

The later versions, which is almost anything past 1967, was a BEHR unit which had parts of it made in Germany and then later in Fort Worth. The fan on those was located in the passenger footwell with the evap roughly in the same place as before.

The good news is that outside of the fan, vents and case almost every part is easy to find and fits almost any under dash unit from the era.

This info may not solve your problem but it will help you to track it down.

More good news.... A lot of this stuff is not only available but cheap. The exception to cheap would be the fan blower motors. They are, in both cases, unique to the application and are getting harder to find.

[Bezant]

Originally Posted by Idle

What year model are we talking about? The early 108s, from 1967, had Thermoking units with the evap sort of built into the area behind the dashboard with the fan right next to it.

The later versions, which is almost anything past 1967, was a BEHR unit which had parts of it made in Germany and then later in Fort Worth. The fan on those was located in the passenger footwell with the evap roughly in the same place as before.

The good news is that outside of the fan, vents and case almost every part is easy to find and fits almost any under dash unit from the era.

This info may not solve your problem but it will help you to track it down.

More good news.... A lot of this stuff is not only available but cheap. The exception to cheap would be the fan blower motors. They are, in both cases, unique to the application and are getting harder to find.

Hi Idle.


I have a 4.5. From what I've read, they had the Thermoking (with a GM A6 compressor).



Classic Center as well as the EPC catalogue I refer to both say the expansion valve is 108 835 03 72, no longer available.

[Bezant]

Got my evap out..time to see if I can leak test it and match the TXV somewhere.

Quite the job.

[Bezant]

I found a TXV with the same threads as mine, it looks like it went on the 220D in the same year. Will try it and hopefully it works!

[Bezant]

update for posterity:

it was the TXV. And the TXV from a 240d with the same threads works fine.