bigragu

Hey all. I am stuck here pounding my noggin on the wall going back and forth on whether or not to stick with R12 or make the change to 134A. My Compressor went out 3 months ago, and with the heat coming our way, I have gathered my parts and pieces to reinstall a new compressor. I ordered one from O'rileys- a Murray brand Sanden 709SD that can either be used for R12 or 134A, depending on the compressor oil you decide to put in(it did not come pre-filled with refer comp oil). My dilemma is that the expansion valve for our trucks(with the metering switch mounted on the passenger side of the expansion valve) is no longer made for our trucks. The switch port is on the drivers side, which may run into the shroud that covers the expansion tank. Some say to reuse the expansion valve, just clean it out. Others say replace it whether I stick with R12 or not. That dilemma #1. Dilemma #2 is the gaskets that go on the condenser to seal refer lines. Those are not available. I have an R12 filter drier so no prob there. I have the mineral oit for the compressor so no prob there. I have an A/C friend with 2 containers of R12 so no problem there. My third dilemma is looking ahead to when this should ever need a charge, replacement, etc. 134A retro parts and Freon are all over. Can you guys give me the pros and cons to either staying with R12 or reto to 134A, please? Also, for those that have switched to 134A, can you all tell me the flush and prep procedures to switch over? Do I need to replace my condenser, refer lines, etc? Which O-rings do I need? Really want to stay with R12, but the future probabilities are in question. Want to do this this weekend. One more thing- how many cans of flush will I need? Thanks, all

maybe368

It is still available, part# 3411283. See my ac renewal thread, here. I converted mine to 134A and have not regretted it yet. Make sure and replace the high pressure valve on the manifold, it also has an o-ring...Mark

rrgrassi

The system was designed for R12. IMHO Stay with that if you can.

If you cannot, then get ready to replace parts that were designed to work with 134a. Like the Expansion Valve, compressor, maybe some hoses, all the o-rings. Also make sure you flush the condenser and evaporator.

bigragu

Another thought to ponder on. If I stick with R12 can I just swap in the new compressor along with a new filter drier, eliminating a flush and dismantling the seals on my expansion valve and condensor? I already swapped out my expansion valve less than 5 years ago

sooty

its always necessary to flush out previous contaminants from the system, if your changing oil or not, oreillys has 1 quart bottles/15. will handle the job, careful which oil your going to use, mineral oil was used in r12 systems, ester based oil can can be used with r12 or r134, pag based oil is only compatible with r134.

maybe368

You said that the compressor failed, that alone can send crud and contaminates throughout the system. Also, read the warranty on your new compressor, usually it is voided if the filter dryer isn't replaced...Mark

bigragu

Filter Dryer is getting replaced for sure as stated, along with the compressor. It's the expansion valve I was questioning if I need replacing. Thanks, though

rrgrassi

The expansion valve can get metal shavings in it from a compressor failure. You should replace that as well.

maybe368

The expansion valve is only around 20 dollars, cheap insurance...Mark

user name

One more thing to consider R134a has been replaced by R1234yf in new cars so R134a may get hard to find in the future just like R12.

j_martin

If it were mine:
I'd clean up the carnage, (clean, replace expansion valve and oil) install the new compressor, and charge it with R12. If your supply of R12 dries up, you can always evacuate it and charge it with Duracool. You can also make up your own mix by mixing 14oz of high quality fuel propane (Coleman) with 1 8 oz can of mountain stove fuel (Isopro) which is a mix of propane and iso-butane. The mix is almost exactly what Duracool is.

About the safety of propane, the insurance folks in Europe did an actuary study on it, and found that there is extremely little danger that you could get it to ignite, much less explode. Even if there was a quick discharge into a flaming sparking crash, the flash fire would last less than 1 second, and likely contribute nothing to the damage or danger. Contrast that to a 20 gallon plastic box under an Astro van, near a potentially red hot catalytic converter and just behind a potentially leaking (spraying) rear transmission seal. Yes, whole families have gone up in flames due to that setup.

maybe368

I had not heard of the new refrigerant, so I did a little checking. I found this info:

Enter Daimler AG. The automaker created a head-on collision test with a B-Class at their Sindelfingen test track that would lead to the pressurized refrigerant being sprayed on the engine. The result in 20 out of 20 test was that the refrigerant burst into flames as soon as it hit the hot engine, while Daimler says that R-134a does not catch fire in the same test. Another unexpected result of the R-1234yf test was the release of hydrogen flouride, a chemical far more deadly to humans than hydrogen cyanide, emitted in such amounts that it that turned the windshield white as it began to eat into the glass.

Here is where I found it. The change in the EU is not required until 2017 and, as you can see, it is controversial...Mark

Bruce M

Do the cars and trucks using R134 have a sight glass at all?
According to Mark, when a R12 system is converted to R134 the sight glass is not used to fill the system.

rrgrassi

On a R12 to 134a conversion, the sight glass is pretty well useless, except for seeing the flow. This is because you use 20% less in weight of the R12. That results in seeing bubbles in the sight glass. With R12, no bubbles means a full charge. No bubbles with 134a means an overcharged system.

maybe368

Hi Bruce, I just checked the '14 TDI and it does not have a sight glass. It is also a 134A system. The best way to charge a 134A system is by weight, but that is only good for a clean, evacuated system. To refill a system that is low, use temperature. I have a pretty good description of how to do it at the end of the thread that I posted in my first post of this thread...Mark