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.

Attached Thumbnails

         

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.

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

__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

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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

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

__________________
14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles

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.

It will work...probably no problem..but with a caveat...

This is the EPA's published position...
Should something happen you may have a liability...
It is illegal in Virginia...

"BEWARE OF FLAMMABLE REFRIGERANTS


It is illegal to replace CFCs with refrigerants consisting primarily of pure propane, butane, other hydrocarbons, or other flammable substances. Vehicles presently designed to use CFC-12 should NEVER be retrofitted or repaired with a flammable refrigerant.

• Over fifteen states and the District of Columbia have prohibited the use of flammable refrigerants in vehicle air conditioning systems, whether they are replacing CFC-12 OR any other refrigerant.
• Vehicle manufacturers strongly discourage the use of hydrocarbon or other flammable refrigerants. Use of these refrigerants poses a safety risk and can void the warranties on air conditioner systems or replacement parts.
• Automobile insurance may not protect owners against liability for damages as a result of using illegal flammable refrigerants."

http://www.epa.gov/ozone/title6/609/consumers/choice.html

__________________
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1971 280SL ROADSTER
1988 300CE TWIN TURBO WIDEBODY
1994 E320 CABRIOLET
1999 C43 AMG
2005 G55K AMG
2008 CLK63 AMG BLACK SERIES

May be in Atlanta, but not in Virginia. No body sell R-12 in Virginia. Even AC shop do not carry them. More over you need spacial lincense to buy them. Getting licnese is not difficult and is cheap. But if I can get way with 3 Dollar can propane instead of 20 Dollars a can for R-12, what is wrong with that? Even if I have add half a can of propane every year. I don,t mind spending 30 dollars in 20 years. That seems reasonable to me.

Sahai

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?

__________________
"I have no convictions ... I blow with the wind, and the prevailing wind happens to be from Vichy"

Current
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You may be right. BUT-

1- EPA jurisdiction is only in USA. What is illegal here as per EPA is legal in some other countries(Europe,Japan,China etc) and what is illegal in other countries may be legal here.

2- In my opinion R-12, R-134a, HC 12, Freeze 12, R-22, R-279(propane) , Butane, Methane, Ethane etc. All are inflammable.
I am going to hook up R-134a to my portable Grill and roast some chicken. If am able to cook chicken, I will send it to you some if I survive. It will be a nice mythbuster.

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.

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 have been using Dura-Cool for years.. great refrigerant and yes it contains propane and several other hydrocarbons. It is compatable with lube in either R12 or R134A systems.. Cools much better than R134A..More efficient.
As for Propane, I refill tanks here and cant be much moisture in it or it would freeze orfice shut in regulators..

I have been running Duracool and Envirosafe for years. Never had a problem.
On a 95 degrees day I get 36-37 degrees from the center vent while driving and 40-45 while in stop and go. Talking about cold air!!
Currently my 92 celica GT is the one with Envirosafe.

__________________
1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified

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.