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

hsahai · #1 06-17-2009, 03:53 PM

I posted this thread in Benzworld Forum under W126 last weekend. I was bombarded with all kinds of replies including insulting,demeaning,abusive and encouraging responses. I want to see what kind of responses I get on this forum. My AC is still working super cool and I AM STILL ALIVE AND WELL.

Here is the copy of that thread and photos. JUST DON'T KILL ME HERE.

AC problem solved with Propane (R-279)

Did I plan for suicide? You are judge.

Problem- I have 560sel 1988 and AC is R-12. For the last 2 summer my AC was putting very low cooling almost none.

Diagnostics-
Inspection- Compressor was kicking in and running. Low pressure hose and lines were not cold. Auxiliary Fan was not kicking in. Pressure gage
Hookup measurement showed low pressure.

My assumptions- 1- Low Freon R-12.
2- No major leak, For last two summer AC was putting very low
Cooling and compressor was kicking.
3- No need for Vacuum pull because of assumption #2.
4- No need for system flush. I will be using Propane(R-279),
completely compatible with R-12 and its lubricant.

Facts and Myths about Propane-

1- It is being used in Europe, Japan and some Asian countries for many years.
2- It is flammable. Yes! but contrary to popular belief R-12 and R-134a are also inflammable. Gasoline in your car is the most inflammable material in your car. In fuel injection car Gasoline runs in fuel line inches below your butt and feet at 35 to 40 psi. That is why back wall of the engine compartment is called Fire Wall. Did you ever think of why it is called Firewall?
3- Propane has very characteristic odor. It is very easy to smell propane in passenger compartment in case of major leak. Just don’t light your cigarette when you smell that. Even then propane has high flash point. Apps 800 degrees F. Propane is non toxic to atmosphere.
4- It work under low pressure head. No damage to O rings.
5- Propane molecules are larger than R-12 and R-134a. Your existing O rings and hoses should good if there is no major leak from before.

My Plan-

1- Customized my own Propane to R-12 charging hoses and gages.
2- Charge my R-12 AC system with Propane.(I just added Propane to my AC)

Final Result-

1- I customized my charging hoses and gages.
2- I added Propane to my AC system yesterday.
3- My AC is working and not cooling but chilling very good. Some times my wife and my kids ask me to shut down AC because it is cooling too much. Now I am Happy camper.

FOLLOWING IS THE WRITE UP OF HOW I DID IT.-

I GOT FOLLOWING ITEMS—

1-R-12 charging hose. I bought from Autozone for 12 Dollars. Yes! The yellow one.
2- Propane mini cylinder connecting regulator. I took it from my old portable gas grill. I was not using this portable gas grill any more.
3- Mini propane Cylinder-1 (COLEMAN). I had one at home.
4- Pressure gage dial from R-134a charging hose. I had one extra so I used that.
5- Two ¼ inch ring clamps. 50 cents.

I DID FOLLOWING PREPARATIONS AT NEXT STEP-

1- I cut R-12 charging hose into two equal sizes.
2- Propane cylinder regulator- This regulator has a safety mechanism. You can not use this regulator as it is. I unscrewed the central pin that goes into the propane cylinder with the help of Vice grip. At the other end of the pin, there is central needle which pushes the internal diaphragm up there by shutting the nozzle under pressure from the propane. It is just like central needle of the Tire nipple. I unscrewed this needle with the help of two ends of the paper clip. Now I screwed back this central pin to the regulator as it was before.

Side nozzle of the regulator has loose nut that screw into the Grill port. This nut has a retaining ring. I removed the retaining metal ring with the help of tiny screw driver and removed the nut. Then I attached the cut end of the R-12 hose with 1/4inch ring clamp and tighten it good.
CAUTION- THIS PROPANE TO R-12 CHARGING HOSE DID NOT HAD SHUT OFF MECHANISM. SO I NEEDED MY ONE HAND THUMB TO BLOCK THE CENTRAL PIN WHILE HOOKING UP THE R-12 CONNECTOR TO THE LOW PRESSURE PORT OF THE AC AND THEN QUICKLY SCREWED THE PROPANE CYLINDER TO THE REGULTOR. THIS WORKED FOR ME THIS TIME BUT I AM GOING TO ADD STOPPER KNOB IN THIS HOSE SOON.
3- R-12 pressure gage.- This was not difficult. I just used the pressure gage dial from the old R-132a charging hose and connected with the other cut end of the second R-12 hose.

ACTUAL CHARGING-

1- I started the engine. Turn on the AC on max. cool. Attached R-12 Charging hose to the low pressure side and attached mini propane cylinder to the regulator as mentioned above. I felt that Propane cylinder was getting chilled that mean it is charging. I was keeping my eyes on the site glass of the drier and Auxiliary fan. As soon as auxiliary fan kicked in and site glass of the drier showed very less bubbles I stopped the charging. Then I hooked up the Pressure gage. Reading came between 40-45. It was 95 degree outside so I left it at there. Shut off the engine. Put all my stuff in my trunk and got into the driver seat started my car went for test drive , I notice that AC was not cooling but CHILLING!!!!!!!!!. Stop by at gas station bought can of soda and came back home. Whew! What a day.

I am posting series of photos in the order I have described. Please review it Finally let me know if I am going to live or die ( propane explosion)

DISCLAIMER STATEMENT-

THIS IS ONLY MY OPINION AND DEEDS. I ASSUME NO RESPONSIBILITY TO ANY BODY REGARDING THIS WRITE UPS. IT SHOULD NOT BE CONSTRUDE AS ADVICE, SUGGESTION OR DIRECTION REGARDING THIS WORK OR MODIFICATIONS TO YOUR AUTOMOBLE. THE POSTER ASSUME NO RESPONSIBILITY TO ANY ONE WHATS SO EVER REGARDING THIS WRITE UP.

Special response expected from- Aurther Dalton.

CWW · #2 06-17-2009, 04:00 PM

Propane is a great refrigerant. It's used in industrial applications because of its high efficiency. And I wouldn't let people give you too much crap.

You're driving around in a machine filled with 20+ gallons of one of the most highly flammable substances in existence (gasoline), another 3 or 4 gallons of highly flammable oils and lubricants of various types, along with flammable and toxic plastics and several gallons of 200+ degree scalding antifreeze.

Compared to the ordinary risks involved with just operating a car to begin with, the 1-2 ounces of propane in the a/c system aren't really going to change the equation. I wouldn't worry too much.

79Mercy · #3 06-17-2009, 04:03 PM

How cold is the air coming from the vents on a 95 degree day at idle? Im looking for a actual temp reading.

LUVMBDiesels · #4 06-17-2009, 05:07 PM

My SDL was converted to R134a. Can I use this method to charge it with propane as well (using the right connectors and hoses of course)

I have a recharging manifold setup with a low, high and fill line for R134a. I am thinking of doing the grill adapter to the manifold so I can keep the gauges and the shut off valves. What do you guys think?

hsahai · #5 06-17-2009, 05:42 PM

Quote:

Originally Posted by LUVMBDiesels

My SDL was converted to R134a. Can I use this method to charge it with propane as well (using the right connectors and hoses of course)

I have a recharging manifold setup with a low, high and fill line for R134a. I am thinking of doing the grill adapter to the manifold so I can keep the gauges and the shut off valves. What do you guys think?

1- Propane do not mix with PEG or ESTER lubricant of R-134a. You need to pull vacuume and flush the system and then add mineral lubricant and Propane.- Don't do it. Not recommended.

2- Why you want to change it to Propane? You already have R-134a system that is already cheap. Stay with it. You should be fine.

jcyuhn · #6 06-17-2009, 06:13 PM

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

hsahai · #7 06-17-2009, 08:25 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

CWW · #8 06-17-2009, 07:34 PM

Quote:

Originally Posted by hsahai

1- Propane do not mix with PEG or ESTER lubricant of R-134a. You need to pull vacuume and flush the system and then add mineral lubricant and Propane.- Don't do it. Not recommended.

2- Why you want to change it to Propane? You already have R-134a system that is already cheap. Stay with it. You should be fine.

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.

tinypanzer · #9 06-17-2009, 08:10 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 · #10 06-17-2009, 08:19 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.

#11 06-18-2009, 02:27 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

salinasboats · #12 06-22-2009, 07:57 AM

Hi just to add to this thread I have been running R12a in my 300E for the past year with no problems .R12a is a mix of butane and propane ,down here in Puerto Rico its legal and cheap.
My system was converted to R134 but was never very cool the change to R12a dropped the temp at the vents by 20 degrees!!
Anyone interested should do a search on the web for info on R12a.
I plan changing the gas in my 420sel when the AC needs work . Steve.

hsahai · #13 06-17-2009, 04:23 PM

Thanks, CWW- Some people just don't get it.

I did not measure the temp. from vent at idle. I going to messure it soon and let you know 79mercy. But Let me tell you Its not cool but COLD AND CHILLING WHILE RUNNING.

Sahai

JimFreeh · #14 06-17-2009, 04:35 PM

Ever since R-12 went thru the roof, I've used propane as an alternative for testing my A/C units.

A number of years ago, I cobbled up a A/C recovery system using my refrigerator compressor cum vacuum pump as the pump and dumping the recovered freon through several filters into an empty propane container.

To test with Propane, I just connect my propane filled container to the system and "Pump them up.". Works well for testing, and I can evacuate the system prior to loading it with preferred refrigerant.

Compared to the total amount of inflammables onboard, the few ozs of propane seem pretty nominal.

Not sure I'd want to load a badly leaking system with propane, for the same reasons I'd not want to drive a car with leaking fuel lines.....

Jim

#15 06-17-2009, 04:40 PM

One observation - you did a HELL of a lot of work when all you really had to do was buy some R12 and fill the system that way. R12 is not that hard to find.