Although I will not argue with anyone with your experience and knowledge on A/C, and I agree with what you say about blended refrigerants, I have heard that R134a is going to be phased out (much like R12 was), and replaced with an HC refrigerant. I am sure there will be a day (maybe sooner than we think) when shops will need at least three machines to deal with the automotive A/C system refrigerants that will be in use. The modern systems that are designed for use with R134a do work very well. The problem is the old systems in our cars, and the inefficient refrigerant we are nearly forced to use. If a new "legal" refrigerant comes along that is phased in for use in new vehicles, and the technology is there for it's use in older systems, then we may be "forced" to use it- HC or otherwise. Without more education, I will not form an opinion either way as to the safety,efficiency, or economical pros/cons of any new HC, HFC, or CFC refrigerant that comes our way. I am open to learn all that I can these things.....Rich

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All Diesel Fleet
1985 R107 300SLD TURBODIESEL
2005 E320 CDI (daily)

LOTS of parts for sale!


EGR block kit
http://www.peachparts.com/shopforum/diesel-discussion/355250-sale-egr-delete-block-off-plate-kit.html

1985 CA emissions 617 owners- You Need This!
Sanden style A/C Compressor Mounting Kit for your 616/ 617 For Sale + Install Inst.

Sanden Instalation Guide (post 11):
http://www.peachparts.com/shopforum/diesel-discussion/367883-sanden-retrofit-installation-guide.html

In contemplating refrigerants, it's helpful to understand that it has almost nothing to do with refrigerants per se, but rather a cosmic battle between patent holders, politicians, big business, auto manufacturers, bureaucrats, militant environmentalists and regulators.

Absent from this list are refrigeration physics, DIYers, auto owners and science.

Once you understand the larger environment, it makes complete sense that perfectly serviceable refrigerants like good old propane and close relatives are shunned - there's just no money there, it can't be regulated and taxed, and the shops would lose valuable business.

Your chances of getting caught running an "unauthorized" refrigerant are close to zero as long as you don't trash a shops stash of recovered refrigerants or brag to an EPA life form.

A good amount of the information out there comes from "interested sources". Just like the "fake news" promulgated by those with a vested political interest there is a lot of "fake" science and information surrounding refrigerants and getting solid information takes a lot of work. "Political Science" isn't just about traditional politics anymore.

Not suggesting anyone break any laws or believe anything in particular....just commenting on current reality.

....and even the claims of the alternative refrigerant purveyors must be taken with the reality that they too have a vested interest

Good luck!

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Current Stable

• 380SL (diesel)
• Corvette C5
• Manx
• Baja Bug
• F350 Powerstroke
• Auburn Boattail Speedster replica

Don't be fooled by scare tactics. The chance of propane or any hydro carbon refrigerant starting a fire in an accident is extremely small.

The Flammable Range (Explosive Range) is the concentration range of a gas or vapor that will burn (or explode) if an ignition source is introduced.

Three basic requirements must be met for explosion to take place:

flammable substance - fuel
oxidizer - oxygen or air
source of ignition - spark or high heat
Below the explosive or flammable range the mixture is too lean to burn and above the upper explosive or flammable limit the mixture is too rich to burn. The limits are commonly called the "Lower Explosive or Flammable Limit" (LEL/LFL) and the "Upper Explosive or Flammable Limit" (UEL/UFL).

Gases - Explosion and Flammability Concentration Limits

Here's a study done on HC refrigereant http://fam-bjork.se/citroen/AC/external/cfca95.pdf

This is copied from the study "There are now over 200,000 car air-conditioners using HC refrigerant and over
400,000 operating years have been accumulated. No accidents in which hydrocarbon
refrigerant caused damage or injury due to its flammability have been reported
to manufacturers or safety authorities yet."

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

""" Extremely Small '''' TRUE... but I do not want to be that exception when it is easy to avoid the chance completely...

I know you are some kind of engineer of some kind...... and that exposition looks impressive to many people..

The problems are numerous with your description... the flammable refrigerant in question would ALSO have OIL dissolved in it.... so under pressure and an escape route it would be sprayed out into the immediate area...

Now you may be too young to have ever used a Manual Choke on a car or riding lawnmower ... or anything..

But the procedure when using a manual Choke... is that you pull it to choke the engine....which causes an overly rich mixture to be entering the cylinders.. and then you disengage the manual Choke

WHILE

continuing to crank the engine...

THUS the fuel to air mixture goes THROUGH the range from TOO Rich.. to ( if the ignition is firing the spark plugs ) to the right mixture... where upon the engine cranks....

If you have hot spots... or sparks ... extant when the flammable refrigerant with its dissolved oil is sprayed into the area... then you risk the natural forces.. like the normal movement of air... causing that ' overly rich ' example to run move through to less rich and potentially flammable concentrations.. just like the manual choke being disengaged with the engine still pulling in fresh air....

And then there are the examples of GRAIN Elevators exploding.... and example of DUST mixed with just plain AIR... and a spark from normal static electricity causing deaths regularly...

That ''' extremely small chance'''' you go to the trouble to share with people... again.... is an example of YOU , the person making the case , of having NO SKIN in the game if that ' small chance' does harm someone.....

You also imply that the authorities which have not been notified yet of ''' manufacturers or safety authorities yet''' would have been notified .. when all the rest of your arguments on this forum display a healthy skepticism of manufactures and governmental authorities..... It may just be that no one investigating an accident which was aggravated by a flammable refrigerant was smart enough to check for that... and if the car burned to the ground... i don't know if they would be able to determine what refrigerant was used...

Anyway... I have expressed my case as well as I can... there IS A chance for a flammable refrigerant to aggravate a crash and that might be the difference between LIFE and DEATH.... and it is EASY TO AVOID that risk Completely...
To me that is a no brainer of a choice..

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Pretty much, except an AC guy in Australia got some press by staging a combustion event w/ HC refrigerant. Duracool long ago paid for an engineering analysis which calculated that even if the full charge leaked into the passenger compartment in 5 min, with no outside air exchange, even that would not form a combustible mixture. Add to that you would need a spark, you would first smell the mercaptin (scent added to natural gas), even tight houses exchange their air w/ outside every hour (cars are leakier), plus most refrigerant leaks would be in the engine bay where hoses degrade faster.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

If anyone wants to use heat on that joint, remove the Shraeder valve innards first since it has plastic seals. You can buy a tool to unscrew it. Some metal caps have an integral tool, so I insure I have one on all my bicycles and some cars. Otherwise, as long as the heat isn't so long and strong as to get to the rubber AC hoses, should be OK. I never had trouble removing that suction fitting, but I have long metric wrenches.

If anyone needs to replace the rubber hoses while in there, search for my post w/ photos.

Re Duracool, I now have it in all my vehicles (7), even the 1996 and 2002 (during compressor replacements). I also use PAO 68 oil, which is best for any refrigerant. All refrigerants can burn when there is a leak, since the oil sprays as a mist and all oils are flammable. Most refrigerants also burn. R-134A forms poisonous phosgene gas (used by Germans in WWI). The new R-1234yc forms an extremely corrosive gas which etched the windshield when M-B ran tests (~2014?), simulating a leak impinging on a turbo exhaust pipe. As a result, M-B refused to ship their cars to France with it, installing the outlawed R-134A instead which upset the regulators. R-134A is a potent "climate change" gas and outlawed in most western countries.

Duracool and Envirosafe are strictly hydrocarbons (propane, butane, ...). It is legal in CA and many progressive states. States that outlaw HC refrigerants are mainly bowing to lobbying by AC shops. If concerned, pour some on the ground and light it like I did. It burns very weakly like candle wax, since must evaporate first and the liquid is cold. It takes only 12 oz to fill your 300D system, so a newspaper seems more dangerous to me. The VW TDI guy sounds like a gomer who never turned a wrench. His condenser most likely leaked because he left no pressure in the system for a year, the PAG oil absorbed moisture (forms acids) which quickly corroded his aluminum condenser. He then flamed Duracool when it later leaked. HC's don't cause corrosion, dude. I would have blown him off too, and one reason I would hate selling to the un-schooled "public".

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans