Quite the pristine specimen!

The Gen I cars have a mechanical evaporator thermostat to trip the compressor to keep it from freezing the evaporator. They are supposed to trip right around freezing, but there's some tolerance and it's not uncommon to see vent temps in the low-mid 30s on them. The Gen II cars have a thermistor sensor that communicates with the pushbutton unit to trip the compressor at 3-5˚C (38-41˚F) so the lowest realistic vent temps you will ever see on a Gen II car is 42-43˚F under ideal circumstances regardless of what refrigerant is being run.

I've been thoroughly disappointed with hydrocarbon refrigerants. When the engine RPM is up and the car is moving, they cool like crazy! Painfully cold! Then you come to a stop light...... 65-70F vent temps are simply not an option for me, sorry. R134a seems to keep the Gen II cars at <55F at idle with the fan on high. Once the cabin has pulled down, it'll significantly longer to creep up into the 50s. Soon as you start moving, down it goes again.

Yes, I imagine the Texas environment is even more demanding of the AC.

Have contemplated doing a hack grafting the innards of cooled seats off a Saab/Lexus/Caddy into the MB seats and tapping a duct into the rear AC conduit...

The heat-gain in this area during the summer is crazy. We routinely get into the triple digits with variable humidity levels and lots of sunshine. The hardest the A/C has to work is when it's over 100 and the humidity is low, vent temps matter! Ceramic window tint helps a LOT, but I haven't yet done it to my 350SD. Despite that, it still has one of the best A/Cs of any car I have access to.

I would be more than happy if you recommend a flushing agent, I spent the last 2 hours searching for one and checking the review, everything says "the solvent is super oily" "did not evaporate" "leaving a film behind" "leaving residue" :-( , Jesus !! I din't know its that hard to find a good product

I've used Acetone several times in the past, most recently on a BMW E23 in March. Keep it off paint or plastic (it will eat both). Evaporates almost instantly and it's ~$13 for a gallon at Home Depot.

You are the man !! can i use 80% alcohol :-) i have a lot :D

By the way is the suction hose (the one with the muffler or filter in it) is this flush-able?

No. It has water in it (20%). You'll spend the rest of your life trying to dry the system out. Acetone sold at the hardware store is 100% strength and will basically flash-dry.

The updated hoses have a large bulge to act as a sort of accumulator on the suction line. It is just a wide spot in the hose, you can flush it. The filter/drier on the high side should be discarded and replaced with a new one. It should be the very last thing installed in the system and a vacuum pulled immediately after connecting it and tightening everything down.

Thank you for the valuable information !!! I am waiting on my seals, expansion valve, the Nylog blue, dryer to start working on the AC. I will keep you updated.

Good luck! Cold A/C is a wonderful thing. When properly charged and functioning, these Gen II 126's have a good A/C system.

I charged my Uncle 2001 buick century this year after a long time of sitting, replaced a couple of leaky hoses, I hope I will get one of these lol

https://ibb.co/y4wMYZm

Might wanna check the evaporator switch or sensor on that Buick. The coil should never be allowed to reach freezing or below, you'll grow frost in humid weather eventually freezing the coil.

So now youre using ES-12a?

Regular or industrial? Did you pull a vacuum?

Max pressures can go haywire with these blends depending upon how they are charged. That can affect efficacy.

That Buick century has only 30K miles in it, he drove it only to church one a week, :-) I was impressed with the AC, really cold you can't sit on the leather seats :D