Info on non-removable valves: Click Here

The 16v I have dose not have a visco fan clutch, it has the magnetic clutch and it was replaced 2 months ago and appears to still be working correctly. the aux fan also seems to be working as it should. It is also on when ever the A/c is turned on as it should.
The engine temp does not seem to be any hoter than normal, 80-90. I seem to have a 16v 190E that actually has no overheating issues as of yet.
As far as if the compressor is kicking off when the ac goes hot, i am not sure. I have been in traffic most times and can stop easily and check.
I think the a/c is staying cold for at least a while even while idling after the car is shut down and restarted and the a/c has gontten cold again. I would say that it stays cold at idle for at least 10-15 minutes, not really timed it, usually, I do a restart and it is cold and I am off. I will start checking it. I typically dont use it as a daily driver so I am just starting to get the whole issue defined. I used it for a 2 hour trip last week on the highway and it was 95 outside and the a/c was freezing us out the whole way, not a single issue. Now it seemed to go hot and then cold again, then hot 4 times in 2 hours today alone.

There is a 3 pole switch on the coolant manifold, it could red or Green.
If IT thinks the engine is overheating it can shut the compressor off.
Try disconnecting the single pin connector & see if the A/C stays cold.

Huh !! Never seen a schrader valve whose insert cant be removed, but clearly they do exist. Yes, then have to be careful as brewtoo said, otherwise the whole hose/fitting could become unusable.

I will try the temp switch trick MB Doc. Is it the sensor up on the top front of the engine, where the other sensors (100deg temp, vac switch over, etc and thermostat is? I'll go look at it.

A/C expansion valve
 

I want to consider replacing some prevent maint items when I replace s few seals and the drier and temp/pressure switch at drier since the freon has to be exacuated anyhow. Can anyone give me advice on how to replace the expansion valve on my 16v? I know where it is, expansion location, but I have never dug to it or replaced one. Is it worth the trouble and time?

If it's not broken, don't fix it. No reason to replace the TXV as routine maintenance.

You would not enjoy getting it out, anyway.

I figure it is difficult to get at and get out. Just didnt know if it was worth the effort to replace it...it is 22 years old and I am opening the system anyway. I think I will probably leave it off my replacment list