AC with Propane- Staying Alive - Page 2 - PeachParts Mercedes-Benz Forum

amosfella · #16 06-17-2009, 08:40 PM

I just changed my system from R134a to Duracool R12a. It seems to be really good so far, although I might have to tweak my system a bit.... It was doing 5C at the sensors in my 95 S320. It was 27C according to my outside temp sensor...
With R134a, the lowest reading I got after checking it with the same sensors was 10C.... It was only 20C outside that day... I was never impressed with R134a. It's all but impossible to buy the small quick fill cans of it here in Canada anyways. The local small town family owned hardware store even stocks duracool here....

tinypanzer · #17 06-17-2009, 09:10 PM

Propane DOES NOT have any odor, much less a distinctive one. It is odorless. That is why they add mercaptan to it so you can smell a leak.

hsahai · #18 06-17-2009, 09:19 PM

Quote:

Originally Posted by CWW

You can add hydrocarbon refrigerants to either oil mix, AFAIK. You just can't mix R12/R134 with the lube intended for the wrong one.

There are lots of people who've installed Dura-Cool (which is about 70%+ propane) directly into 134 systems, with zero problems whatsoever. So if something that's 70%+ propane doesn't cause any problems with the synthetic lube oil used in 134 systems, then I don't see why 100% propane would cause any problems either.

Thanks, for this info. CWW--

I need to add R-134a to my 1995 Mercury Villager. I think it should be fine if I just add propane to it offcourse with some PEG oil.

hsahai · #19 06-17-2009, 09:20 PM

Quote:

Originally Posted by tinypanzer

Propane DOES NOT have any odor, much less a distinctive one. It is odorless. That is why they add mercaptan to it so you can smell a leak.

Yes! you are absolutely correct. It is easy to smell leak I suppose.

79Mercy · #20 06-17-2009, 09:22 PM

I have been using duracool in my 79 280CE. Its very coold when it like 85 degrees, but when its near 95 its OK at idle(60-65 degree), when driving its about 55 degrees. It keeps me from sweating, but it doesn't freeze me out.

hsahai · #21 06-17-2009, 09:25 PM

Quote:

Originally Posted by jcyuhn

It's been a while since I used to hack auto a/c systems. My recollection is that a blend of propane and isobutane is required to get somewhat near the same pressure/temperature curve as R-12. Doesn't straight propane have runaway high side pressure at high temps? Depending on the percentage propane in the system you may be putting the system under quite a bit of stress.

Second, isn't grill gas quite wet? You're adding water to the system along with the propane. Water in combination with R-12 is not good, the two react to form acids that then corrode the system from the inside out.

FWIW I'm in the camp that is not the least bit concerned about flammability of hydrocarbons in the a/c system. Of course, I don't smoke either

I don't think there is any water in the propane tank. Yes! Propane has high pressure curve but only 30 % of the AC capacity is needed to fully charge the system. I only added may be 6 oz. at that point my AC started working fine

LUVMBDiesels · #22 06-17-2009, 10:30 PM

My reason for wanting to switch over from R134a is that the system was supposed to run on R12. When it was converted, they just evacuated the system changed the Schrader valves and pumped it up. It does not cool down the black car very well at all.

I figured if going to propane was easy and cheap I would try it and see if I get better performance from it over R134a.

If propane will cause more issues than it will solve then I will leave it alone

What does he say?

Kestas · #23 06-17-2009, 10:53 PM

The reading I've done tells me that you can't use 100% propane because the propane won't carry the lubricant through the system. Butane is added at the 40% level because butane can carry the lubricant.

hsahai · #24 06-17-2009, 11:19 PM

OK! Butane cans are also very cheap. I saw those at store for 4 dollars -4 cans that are used in portable table top stove. But these can have different nozzle I need to figure out how to connect it to the charging hose?

#25 06-18-2009, 03:27 AM

I live in the Red River bottom land in the midst of lots of farmers. Most of them use propane in their tractor a/c's beginning with the first leak that occurs.

I have yet to hear of any fatalities or explosions with their systems.

Will I use propane for a refrigerant in anything that my family or myself ride in? Not in a million years.

R12 is still plentiful and coming down in price. When I have a problem, I find the leak, fix the leak, account for the oil loss and charge with R12.

Without doing any research, I THINK that propane is a legal refrigerant AS LONG AS the system is fitted with the proper, unique fittings and properly marked. This is required by Federal Law REGARDLESS of what alternative refrigerant is used.

It's your car, your conscience and your family, so it's YOUR business!

Best of luck,
Larry

#26 06-18-2009, 03:36 AM

Quote:

Originally Posted by LUVMBDiesels

My reason for wanting to switch over from R134a is that the system was supposed to run on R12. When it was converted, they just evacuated the system changed the Schrader valves and pumped it up. It does not cool down the black car very well at all.

I figured if going to propane was easy and cheap I would try it and see if I get better performance from it over R134a.

If propane will cause more issues than it will solve then I will leave it alone

What does he say?

Although I am not a fan of refrigerant conversion in spite of the fact that I've done a number of them, it CAN work in most cars IF done properly. Simply installing fittings, evacuation and charging is NOT doing it properly.

For proper conversion, you need to AT A MINIMUM, put in the proper amount of Ester oil, change the filter/drier, evacuate the system and charge with 134 beginning with 70% of the specified R12 volume. You then monitor the system closely and if necessary add one ounce of refrigerant at a time until the system is cooling properly. You also are CLOSELY monitoring high side pressure to see that it does not get too high. In most systems 250 high side is on the edge of too high.

I have only started this method recently and have been amazed that the proper volume is as little as 70%. Too much will kill the performance of the system.

The BEST way to do this is with a charging scale that gives you have ounce resolution. The point where the system is over charged is a very fine line, that's why you add only a half ounce or one ounce at a time while monitoring high side pressure to see that it doesn't "run away."

LUVMBDiesels · #27 06-18-2009, 08:46 AM

Quote:

Originally Posted by LarryBible

Although I am not a fan of refrigerant conversion in spite of the fact that I've done a number of them, it CAN work in most cars IF done properly. Simply installing fittings, evacuation and charging is NOT doing it properly.

For proper conversion, you need to AT A MINIMUM, put in the proper amount of Ester oil, change the filter/drier, evacuate the system and charge with 134 beginning with 70% of the specified R12 volume. You then monitor the system closely and if necessary add one ounce of refrigerant at a time until the system is cooling properly. You also are CLOSELY monitoring high side pressure to see that it does not get too high. In most systems 250 high side is on the edge of too high.

I have only started this method recently and have been amazed that the proper volume is as little as 70%. Too much will kill the performance of the system.

The BEST way to do this is with a charging scale that gives you have ounce resolution. The point where the system is over charged is a very fine line, that's why you add only a half ounce or one ounce at a time while monitoring high side pressure to see that it doesn't "run away."

I doubt the PO who had the R143a conversion done on my SDL followed your methods.
Maybe it is time to rip out the conversion and either try to go back to R12 or have it done right.

#28 06-18-2009, 08:59 AM

Quote:

Originally Posted by LUVMBDiesels

I doubt the PO who had the R143a conversion done on my SDL followed your methods.
Maybe it is time to rip out the conversion and either try to go back to R12 or have it done right.

To "rip out the conversion" as you describe it, would probably be about the same expense and trouble as going back to R12. You will have to do a thorough system flush to get the oil right and replace the r/d. If you're doing that, then the only difference is going back to the original fittings, pouring in different oil and charging with R12.

My $.02,

#29 06-18-2009, 09:07 AM

At least on the 123 chassis, R12 is really the only acceptable solution for Atlanta summers...

CWW · #30 06-18-2009, 10:50 AM

Quote:

Originally Posted by Kestas

The reading I've done tells me that you can't use 100% propane because the propane won't carry the lubricant through the system. Butane is added at the 40% level because butane can carry the lubricant.

Ok, but if the gas won't accept the lubricant, then all of the lubricant stays in the compressor anyway. Which, if you think about it, is the part that needs lubricating. So I think there's a high chance that these warnings about lube oil circulation and ruining your compressor might be total B.S. Also, AFAIK, the reason butane is added is to change the behavior properties of the gas itself to be closer to the specs the system is designed for, I'm not sure it has anything to do with the lubricating oil.

Also, the other thing you're missing is, we're talking about hydrocarbons here. The gas itself is ALREADY a natural lubricant.