134a, which is not compatible with R12 so the system must be empty.

 

I see now, just trying to figure out why you quoted me.

 

That door can also control the temperature of the incoming air, I worked on a truck where the air was warm, found the rod disconnected from the door, fixed it, turned the selector on cool, and the air blew cold.

 

Yes it does. When set to max a/c that door closes to recirculate the cold air keeping it as cold as possible. On regular a/c it opens to allow fresh warmer air in which it has to cool down again.

 

The freon your refering to is 134A. There is a kit from local automotive stores that you need to get in order to convert. It would be a good idea to get someone to throw a set of gauges on this and see what your pressures are to make sure that it is indeed low on freon and not another problem within the system. If you have a friend that understands the mechanics of an A/C then I would do this first. I didn't catch what year your truck was, but the answer to your question concerning wouldn't the freon have all leaked out by now all depends on how big the leak is. When the o-rings wearout at the quick disconnects or you have a pinhole in the system it all depends on where it's leaking from. Actually o-rings don't wearout they dryout from lack of use. All newer systems don't have this problem because on newer vehicles the A/C runs year round when the heat is on to keep the temperature steady inside the vehicle. Now, back to the kit, if your system is low they now sell conversion kits that will neutalize the old freon and oil. The system will still need to be pumped down regardless. If this kit is not available then the changeout is labor intensive because the filter drier and all of the oil needs to be evacuated from the system. Hope this helps and sorry for such a long discertation.

 

"Freon" is R-12, not R-134a.

Freon was a brand name for R-12, or Dichlorodifluoromethane.

It is a much better refrigerant then the new R-134/a but was "banned" in response to the 'hole in the ozone layer' fraud.

You need an EPA cert/liscense to buy R-12.

If you can get it, and your system still uses R-12 I wouldn't bother converting it.

Some of us may still remember the good old days when you could set a bottle of pop in front of the A/C vent and it would frost it for you.

 

I knew that was coming. I may buy Puffed Rice at the supermarket but I still call it Rice Crispies.

 

Actually "Freon" is Duponts trademark name for its refrigerant line but most people outside the commercial refrigeration industry associate it with R-12 or refrigerants that contain flouro carbons that were banned.

 

Sir,
BrodyF150 was talking about old freon. You asked who said anything about old freon. No biggie, I just answerd your question, I did not quote you. If I offended you then my apologies.

 

i have done industrial H.V.A.C.R for the last 8 years and am loving this.

step 1 check pressure
step 2 check to see if the a/c clutch is engaging if press is too low the clutch will not engage
step 3 make sure you don't have a leak if you add a can of 134a and the clutch starts to work replace all the seals/o-rings and recharge

but the pressure is the first thing we need to know. from there we can walk you through the cheapest rout to take