D100 A/C R12 to 134a conversion. Q's and unknown part..

Okay I have an 1989 3.9 v6, D100, that I'm trying to get the air conditioner working on, this next week. I have a good compressor for it (which was missing when I bought it) and everything else is there and looks okay.

I also bought a new gasket kit and dryer. Bought some gauges and a vacuum pump that works with an air compressor.

I still need r12 to 134a conversion fittings, and I guess to find a sticker?



I notice there is a pressure switch on the low side that is like a round plastic disc by the firewall. I was wondering if the pressures are different from the r12 to 134a and if I will need to replace that switch??? The only one I can find is a -all metal one, labeled 134a at the parts store.

Also there is this piece on the low side line that connects to the compressor. The piece is on a canister. I don't know wtf it is. It kinda looks like a sensor missing a wire connector, but I didn't find a wire that would connect there. Better yet, here is a picture.

When the a/c works on these trucks, is it very good? Worse with 134a or about the same?

Any suggestions?

I really do not want to spend another Texas summer without air conditioning, am kinda excited. Thanks.

That piece is called a muffler. Besides changing the seals, a R134 system uses a condenser that flows better than the R 12 system. A R134 system uses a charge equal to about 2/3 3/4 of what a R12 system uses.

I looked up a new condenser, and its $150!! A/C for these trucks aren't cheap. Especially looking at what a new compressor and hoses go for!

From the pics of a new condenser, I do see how the tubes are parallel, as opposed to series like the unit I have. Seems, it would flow a lot better.

Is the muffler the piece hanging off the canister? Or the canister itself is called the muffler? If so, what is the piece that looks like a sensor?

Thanks.

If the system still holds a little pressure you could top it off with some R134A after you added some Ester oil (works with both R12 and R134A).

At least that's what I did on an '89 Taurus, put in two or three little bottles of Ester, then about 2 1/2 bottles of R134A.

The pressure switch wouldn't let the compressor run so the oil and the first couple of bottlesof R134A, I put into the low pressure side using a heat gun on the bottle. At that point the compressor kicked on and I added the remainder of the R134A with engine running, A/C on high, windows open, and a thermometer stuck in the dash vent. When it got below 38 degrees F I stopped adding the R134A.

This is "ultimate shadetree" mechanicing at its finest, not very elegant, but that A/C system worked through three summers like that.

PAG oil will not work for R12, don't use it on a mixed system.

There isn't an A/C shop who will work on a mixed refrigerant system, at least not to my knowledge. That means once you step out over that edge you can't go back. My '89 I knew was never going to see the inside of a refrigeration shop so I had at it.

The books are full of warnings about condenser insufficiency and compressor failures, these MAY happen but they didn't happen to me. I didn't change one other part from what I wrote above, except adding the R134A port conversion fitting to the stock port.

R.

PS: I hear the price of recycled R12 is coming down as demand ges down. Or smuggle it in from Mexico.

PPS: There are Federal laws against these procedures, so I am expecting the FBI to be breaking down my door at any moment.

Thats a pop off relief valve on the side of the muffler. I mixed 134 with 12 in my 89 cummins and had no issues

Ignore all the advice here and fix any leaks; then recharge with R-12.

Quote:

---

Ignore all the advice here and fix any leaks; then recharge with R-12.

---