[DeTomaso] A/C freon

[Larry Finch]

Is there anything that can be added to a freon system with freon other  
than freon?  

........In reality, no. But you will find plenty who will say otherwise. While their "experience" may lead them
to believe what they say is true, mixing anything with the original R12 gives you a bastard system.

Any shop that gives a damn about their equipment will always do a check on any system prior to doing work,
looking for non-OEM mixes. Such mixes can ruin their $2K -$4K A/C machines. If you intend to fully replace
your entire - entire - system the next season or plan to sell the car to some unsuspecting sucker, you may be
able to augment the R12 with one of the offerings on the market. Truth is, NONE of them are approved to mix
with R12.


How do you convert a freon system?

......... In a stock Pantera, this is what I would do, at a minimum:

-- new rotary compressor
-- new drier
-- ALL new lines and use new-style o-ring fittings
-- Flush condenser
-- Flush A/C portion of the under-dash evaporator 
-- check integrity of the evaporator heater core lines - pressure check
-- Make sure small screen is still in place in the expansion valve, and that it is clean
    NOTE: an R12 expansion valve is not truly designed for 134A It may work....but perhaps not optimally
-- add a high-low pressure cut-off pressure switch

While you are at it, you should consider:

-- Upgrade condenser to a newer parallel flow style with shrouded fan,
   or buy and install the double-sized tube and fin replacement for the original tube and fin unit.

-- buy and install the upgraded under-dash evaporator. $500 on eBay, $600 at the vendors

-- Buy a new dash blower motor - one speed or 3-speed, control it with a DC motor controller
     http://tinyurl.com/30-amp-controller
   You may be able to use the same seller's 15 amp unit - check your motor rating

R12 is NOT illegal, just expensive and getting hard to find a shop that will work on it.
BUT, it is a better refrigerant than 134A, which is soon to also be phased out for yet another "fix"

Of course, you can toss the entire system and start from scratch, using items from sources like
Vintage Air. Or track down a used Maserati bi-Turbo unit and control panel, as used on the later
Panteras. Of course, you'll need to cut away part of your front firewall and rebox for structural
strength to get that unit to fit. And then figure out how to make it work.

Many vendors offer complete kits. One stop easy shopping. Locate a good local shop that you know you can trust,
and have them handle the install.

To convert an R12 system - PROPERLY - is neither easy or cheap.

Know this before going into it and you will have far fewer headaches.

Larry