R12 AC recharge

The service ports are on top of the compressor and should be easily accessible from the engine bay. Shouldn’t be any need to go through the wheel arch unless you’re planning on removing the compressor


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The low pressure one is the lower one .Just lean into the engine compartment from above .

I use “ Ezichill “ You need an adapter because the original compressor was R12 .
Modern recharging is done with R134 (?) .This is claimed to be ozone friendly.It needs updated pipes and other upgrades ( doable ) because it’s a smaller molecule and leaks out of the older R12 compatible equipment.
Anyhow fortunately” Ezichill “ seems to work .

When your R12 ,s exhausted I guess it all will need converting to run on today’s R134 or what ever ?

 

Depending on your local laws/availability, the propane based refrigerants work extremely well, lower head pressures as well as a lower charge volume than R134a (from memory i think my charge amount was about 480 grams ). Work as a straight drop in gas to R12 system. I have vent temperatures of around 6 degrees on a 32 degree day with an unmodified system.


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Its Iso Butane (R600a) that could be used as a replacement for R12. Propane refrigerants are usually used to replace R22. Good refrigerants but highly flammable and not necessarily legal in your country for automotive use.

 

If you need a recharge after only 1 year, it is important to resolve the leakage before recharging. This is especially true if you are using R12 since it is both a greenhouse gas as well depletes the ozone (R134 is "only" a greenhouse gas). It is nasty stuff.

Having said that, I use R12 in two of my antique cars. It works great. My 308 was last evacuated and recharged 5 years ago and is the system is still blowing cold (… although the whole system is grossly undersized for the car).

I have been told (but have no direct experience) that the performance difference with R134 is exaggerated. It is apparently pretty good stuff too (and "only" a greenhouse gas). The problem is inadequately flushing an R12 system since passageways are blocked with sludge when R12 and R134 oils are mixed. Again, I am not an expert in this.

I apologize for drifting off topic from your original question.

 

Hi Friends R 437 A is the best solution as R 12 substitute , only evcuate the sistem change the filter and fill it , with no change , it works perfectly , i used it in my 308 Gt 4 , porsche 924 turbo and porsche 928 S 4.

 

I've been using propane-based refrigerant (DuraCool) in my 328 for many years now and have been very pleased with it. R134 (converted from R12 by the previous owner) was very poor in comparison. DuraCool and doing all my own AC work (which I had to learn to do due to generally poor ac tech work) has raised my 328's AC performance in hot, TX weather from poor to fair! I don't think the system supplied with the car can do any better than that!

 

There is a great book to learn how to DYI AC:

https://www.amazon.com/Just-Needs-Recharge-Mechanic-Conditioning/dp/0998950718

 

DO NOT waste that liquid gold R12 until you locate and repair the leaks.

 

A shop will pull a vacuum for a couple of hours, and if they don't see a pressure increase, will call it good.

Maximum vacuum possible is less than 15 psi pressure differential. At home, you can test more leisurely and thoroughly by pressurizing the system with nitrogen to get a 100+ psi differential and let is sit for days. The book covers this.

I recently restored my a/c on another car (my beloved 1987 BMW 325i convertible if you must know). There were 5 leaks. The last one was actually porosity in the middle of a hose and leaked 1 psi per day under 100 psi nitrogen.

 

"A shop will pull a vacuum for a couple of hours, and if they don't see a pressure increase, will call it good."

FWIW, the shops I took my 328 to for two failed attempts at proper charging pulled a vacuum for about 20 minutes at most.

Dinoart, Re charging to 40PSI, what made you decide on that number? Was that static pressure or with the system operating/compressor engaged?
The optimum pressure varies with ambient temperature and the refrigerant used.

FWIW, overcharging will cause poorer cooling than undercharging and it can also damage the compressor. The shop that I took my car to the 2nd time used a fancy modern machine to do the work and then the tech said "I added a few more ounces of refrigerant to be sure it cools really well." When they turned on the system the compressor immediately locked up/ruined the belt. They had to install a new belt and pull some refrigerant back out of the system to get it working. That experience started me on my "buy the equipment/learn to do A/C myself" path.

 

One of the common problems I see with airconditioning is people doing service at home with cans of refrigerant from the parts store, instead of using the proper equipment to fully evacuate, vacuum, and correctly charge the system.

AC service isn't like oil. You don't just drain and fill, or regularly top it off if it's a bit low.

 

A problem I see with a shop that creates a vacuum for an hour is that in one hour there may not be enough time to notice a small leak. Furthermore, the pressure difference is only 14.7 psi. With refrigerant in the system, the pressure difference is higher and totally dependent on temperature and is always greater than 14.7 psi, existing 24 hours a day, 7 days a week. When the system is running, the pressure in some parts of it is much higher. The greater the pressure difference, the more tendency for leakage exists.

 

I don't know anyone that pulls a vacuum for 2 hours in order to find a leak...10-20 mins is the regular procedure. Doing it for 2 hrs is to be sure moisture is out of the system.

 

Pr

provided the system still has pressure in it, you can just top it up- as you know it cannot have an air. Once you have lost the charge it will have air so you are back to the vac pump.

 

I am amazed there is any still about as its been banned in europe for over 15 years i think now. How come you can still use it .

 

Not supposed to really. What is left is NOS stuff mostly.

 

Well, if any refrigerant has leaked out, then air and moisture have leaked in.

 

As

long as u ha