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.

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