I made the TXV adapters primarily so I can pressure test the evaporator. Only if it tests good will I proceed with further work. A new one is difficult to find (nla) plus I will not r&r the evaporator being such a big job.

What is the time table for R134a discontinuance? It'll be a repeat of the R12 saga, people hoarding it, price skyrocket. Stock up now while the price is still reasonable.

As for blowing out oil from evaporators and condenser. I did that with the evaporator only but have not done the condenser yet.

I rigged up separate connections directly to both pipes of the evap, ball valve on each hose, the outlet hose was a clear 3/4" i.d. 4 ft long PVC hose with 1/8" walls emptying into a 5 gallon glass water bottle. I first blew 100 psi compressed air into the evap and nothing came out at the start of the clear hose. Tried that a few times same results. I then pressurized the evap, closed the input ball valve, then opened the output ball valve to give it a quick pressure release. Nothing came out at the first time. I repeated that a few times and the third time creamy looking thick green oil (from the dye) came out which stuck to the clear hose (so thick it would not run down the walls). I must have done that 6 times, each time a little more cream came out. I was wondering why the oil is so thick. I later learned that air was mixed with the oil during the sudden pressure release and made whipped cream. After it sat in the sun for an hour, the creamy oil separated from the air and ran down the top/sides of the clear chose and sat on the bottom as a yellowish clear oil. I estimate at most 3 tablespoons came out so far, and there is more in the there. From this experience, I say you cannot just blow all the oil out of a serpentine evaporator or condenser with compressed air. Not that easy. I plan on using a solenoid pump and cycle solvents thru it to flush the rest of the old oil out.

Good information and a lesson on the need for both patience and persistence....

True, but one must also have the tools or ability to make custom tools like adapters. I want to be able to pressure test each component individually. I am glad I pulled many of the AC hoses (except the TXV hoses) and parts off a 240D and 300D. The fittings from the hoses allow me to make adapters for component testing.

The shiny #10 to the TXV came in the mail this morning and was easy to make an adapter from by taping a 1/8 NPT thread in it and screwing in a 1/4 SAE flare.
http://i31.photobucket.com/albums/c3...806_122139.jpg

Here it is being used to pressure test the evaporator by itself at 1.001 MPa (145 psi) Argon. Last night's test of the evap with the hose on the TXV adapter was encouraging. This test will be definitive whether my evaporator leaks or not. I'll know in a day or 2.
http://i31.photobucket.com/albums/c3...806_124228.jpg

Thanks for all the advice.

Fine, you guys forced me to flush the evaporator. What I did was drill a hole through the smaller holes of the old expansion valve and blew it out and cleaned it with flush. Then I installed it and the hoses.

I ran the thick hose through the firewall and fitted a funnel to it, while routing the thin long hose through the cabin and into a gallon water bottle. I poured in some AC flush from a bottle through the funnel so that it would fill up the evaporator and I let it soak for half an hour. During this time I hung the catch bottle off the turn signal stalk.
http://www.peachparts.com/shopforum/...959%5B1%5D.jpg
http://www.peachparts.com/shopforum/...962%5B1%5D.jpg

After this I moved the catch bottle down onto the ground outside the car with the long, thin hose still attached. I then blew compressed air through the thick hose in the firewall as it drained into the catch bottle.

The flush is a clear liquid. What came out into the bottle was bright orange and not a speck of dirt. I'm not sure if the orange color is from a leak dye or the color of the old oil. I flushed until the fluid came out clear. I then blew compressed air through until nothing was coming out, then disconnected the hoses and then blew compressed air through the evaporator again from inside the car. Then it will be left open to dry out for a few days. The old expansion valve was held together with JB Weld.
http://www.peachparts.com/shopforum/...963%5B1%5D.jpg

Heck, we had forgotten you were working on your AC... we were just in ' talk amongst yourselves ' mode.... trying to figure out the fSm combined with ' what is possible'....
But I am sure you will sleep better now that yours is cleaned out....and the pictures will help others tackle theirs also...

I have seen that color before when flushing, and I believe it is the oil that made it that color.
EDIT: by the way, that looks like the twin to my car!

Yeah, it's a white 1991 350SDL with grey interior.

Here's another question--is the little tube at the saucer end of the expansion valve supposed to touch anything? It looks like it floats out in nowhere land.

The expansion valve came from the local auto parts store. It was listed as Murray brand, but the stock photo showed an Englehof made in France. When we looked at the box, the box was labeled Made in China. The valve had a big sticker over the original sticker. So I peeled that sticker off, revealing an Englehof R134a sticker underneath. No indication of where it was made, though, but probably China.

' Little tube' ... how long is the tube you are talking about ?

It's this little tube thing on the end.
https://www.horsepowerfreaks.com/get...982B30AB-2.jpg

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 ?

http://www.achrnews.com/articles/85048-tech-tips-for-thermostatic-expansion-valves

http://www.tpub.com/ase2/69.htm

Some expansion valves have a sensing bulb on the end of a tube. Our cars use a block type expansion valve so the sensing bulb is built into the valve. That's why it gets wrapped in insulation, and why the suction line runs through it.


-J

So in other words, leave it alone.

Okay, I will just put the new insulation halves over it and call it good. I remember reading somewhere about an expansion valve having a sensing bulb that was supposed to touch the upper part of the refrigerant pipe so it senses the gas temperature and not the liquid or something. Sounds good to me.

If you look at those url's I posted you will see a bunch of those types..