A/C System

rhkcommander

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Great info in this thread.

Propane works great from everyone I've heard that done it. I never understood the stigma against flammable refrigerants. Had a guy think I was crazy suggesting it, and he drove an alcohol racer.

I'd rather have a couple ounces of propane leak, versus alcohol leaking. Or gasoline. Wiper fluid is flammable too usually with its content, some use it in their diesel intake aka **** or methanol injection. For a while propane in the intake was a thing too for more combustion power.
 

Garbage_Mechan

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Been through this a lot back in the days when R12 was phased out. Most things did not have a condenser suitable for R134. On the fleet we had to do everything by the book (no propane based refrigerants) so most got the condenser replaced with a R134 capable unit. If not changed a constant cycle of problems would start once the temp went above 100 (up to 113 or so in CA Central Valley). Usually blown high pressure hoses, R134 blown out the high pressure relief and blown compressors. Not to mention poor cooling performance especially at idle / low speed. Once the condenser was swapped out This all went away. The advice on adding a pusher fan to the condenser was something we did especially on things that idled or moved slowly a lot such as landfill supervisor pickup, idled a lot.
 

Garbage_Mechan

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My 91 came with Duracool, a propane based refrigerant already on it when I bought it from the original owner in 2001. For about 15 years I put a can of Duracool in it in the spring.....good to go. Good cooling performance too. What I didn’t think of was to replace the oil that had been leaking out with the refrigerant through the compressor seal over the years so the compressor locked up. It was my fault, it owed me nothing. Sooo, I installed a receiver drier, orfice tube, high pressure hoses and a parts store reman compressor I got on a parts truck after using about a gallon of flush to get the black sludge of death out. Refilled with Duracool. Works great, haven’t added in 4 years now. Love Duracool.
 

Garbage_Mechan

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Not sure why there is so much negativity regarding propane based refrigerants. Works for me.
I have also used Johnson’s Freeze 12. A friend got tired of the negativity and gave me a canister of it. My 71 Datsun B110 1200 coupe has hang on air and didn’t perform well on R134. Poor idle/low speed performance. High head pressure would nearly stall the 1200cc engine. I switched it over to Freeze 12 and no more issues. Still works great.
 

Booyah45828

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Hydrocarbon refrigerants seem to work great by all that have used them.

I've never done it, because I was told it's illegal for me to do so. I'm a mechanic and am "certified" to repair motor vehicle ac systems through MACS/EPA. The certified is in quotes because I think it's all a joke when they sell cans of r134a to anybody that wants it.

But, I'm not going to risk losing the shop and everything else I've worked for in a lawsuit from using propane in an ac system. It'd be just my luck that something of that nature would happen.

Once you understand the Carnot cycle, you can understand how AC systems work, and how different refrigerants have different operating pressures and effectiveness.
 

franklin2

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Booyah what is your opinion on putting on a more modern design condenser when changing to 134?

The larger more modern designs are better, easier to clean, etc. Getting them to fit and getting the lines hooked up becomes the sticky point.
 

aggiediesel01

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The larger more modern designs are better, easier to clean, etc. Getting them to fit and getting the lines hooked up becomes the sticky point.
I swapped to R134 in our '91 in 2000 right after I bought it and was always disppointed with it's performance especially around town. Probably around '04 I put a condenser from a '95 power stroke on our '91. I had my local Napa make up 2 new hoses for me that had the '91 ends on one side and the '95(R134) for the condenser. I think it only cost ~$60 for the two of them. At the time one of the fittings was considerably more expensive than the other 3 and had to be ordered in but I can't remember which it was but they had 3 of them and the hose in stock and made them up for me while I watched. They're still on the truck. I also had to get the later hood latch support b/c the new condenser was so much deeper. But that condenser and a variable orfice tube and it was very effective at keeping the extended cab cool.

With hindsight knowing how good the 12 alternatives have been I would probably opted for one of those choices first until it was time to replace major components and then go ahead with the R134 swap with the bigger condenser.
 
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franklin2

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The larger more modern designs are better, easier to clean, etc. Getting them to fit and getting the lines hooked up becomes the sticky point.

I miss-spoke about the cleaning.

The newer ones are a more efficient design, but they can't be cleaned, they have to be replaced if you have a catastrophic failure of the compressor. The older style found mainly on the r12 systems are less efficient, but can be cleaned.
 

79jasper

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I use this stuff in all my vehicles.
https://www.es-refrigerants.com/products/w/id/31/t/134a-replacement/
It doesn't require pulling a vacuum at all. I usually do it anyway to reduce humidity in the system, but on a quick empty and refill I have skipped the vacuum and it cools fine.
I remember one member not having good luck with it. But I don't know if he had another issue, or just swapped to another refrigerant.
Maybe it was @chris142 ?

Sent from my SM-N960U using Tapatalk
 

Howard Welte

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I'm also a newbie to A/C to. If you suck down the R12 system into an old propane take, will the R12 / air from the system settle in the propane take so you can vent off the air and leaving the R12 in the tank so you can reuse it ?. I have several old refrigerator compressors I could use to rig up a recovery system. When you use propane, is it 100% propane or a propane / R12 mix ? Also can you use a compressed air line oilier to inject oil into the vacuum side of the vacuum pump filled with mineral oil to keep the pump lubed ?
 

SkipBurney

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I converted mine over to 134A, I added a can every spring and its cold all summer here in Georgia. It usually needs a can each spring. Good luck finding any R-12 and if you do you will have to take out a second mortgage to pay for it
 

Macrobb

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Also can you use a compressed air line oilier to inject oil into the vacuum side of the vacuum pump filled with mineral oil to keep the pump lubed ?
Just pull the compressor, tip it on it's side and add oil there. Spin it a couple times to get the oil down into the pump, then tip it back straight again.
Just make sure it's a light-weight oil.
 

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