And if I recall you need a special permit for r12

Per that your car is designed to operate best with R134a

You got quoted pretty high - 12oz can of R12 goes for $30-40 a can. Not $100.

And yes, R12 does work better (i.e. COLDER) if the car was originally designed for R12 operation. This margin increases SIGNIFICANTLY in stop and go traffic, where duct outlet temperatures can approach ambient temperature.

The OP never said what year his car was, but I'm guessing it's older and was originally equipped with R12.

To the OP - do not mix the two. Start from scratch. Drain the system, put in the proper oil, fix your leaks, and then go back with R12 if you can 1) afford it and 2) get it installed legally and properly

1. the molecules are larger and don't leak out as easily as R134a does...R12 does not require barrier type hoses, R134a does.

2. r134a has only 90% of the cooling capacity of R12 pound per pound

3. R134a operates at higher system pressures compared to R12

4. R134a has NO cooling reserve compared to r12. if your charge is down by as little as 2 oz with r134a, you will notice a loss of cooling performance. you could have a r12 system down 50% and still have good cooling performance.

5. R12 can withstand higher ambient temps than r134a in an engine compartment

but putting r12 in a car designed for r134a is a no no becuase of the different oils used........and it is only legal to put r12 in cars originally designed for it.... also if you have put r134a in a car and you want to go back to r12, you gotta flush the system and replace the receiver dryer......

http://img355.imageshack.us/my...0.jpg

4/7/09

4/7/09

Another point is the lines. Good luck finding someone to hand build you a manifold set that will charge 12 and accept 134 service fittings. They'll just laugh and kick you in the nuts. The ports are smaller, the threads are different.

http://img355.imageshack.us/my...0.jpg

It won't be long before r134a is gone, too. Even r134a is bad for the environment.

The service fittings for r134a are a quick-disconnect type fitting. R12 is a screw-on type fitting. If you find someone who will make an adapter for you, as was said before, kick yourself in the nuts and save THEM some time.

R12 and r134a are not friends. They yell at eachother all the time. They fight, pull hair and just plain don't get along. DON'T mix them. I like cheese.

"The more you know, the less you make."

4/7/09

I bought conversion fittings for my quarter inch nipples on my HVAC manifolfd so I can thread on a threaded end of a R134 hose. I bought these so I could load gases into a r12 system where you need a smaller thread on the high side nipple. You can buy a R134 conversion fitting that screws onto these smaller nipples on some cars, like a toyota. Then I use the 134 high side coupler to connect and this way read the high side pressure.

You could easily use these fitting to load R12 into a R134 system. I have not done it but R12 is compatible with Ester oil. It is a curious thought because it would seem that given the large condensors in later 134 systems That R12 would be very cold in a 134 design do to the greater release of heat. The high side pressure should be lower I would think as a result, not unlike hose a condensor down with water.

I do not think the Compressor seals would be a problem and the hoses are not a problem.

Only the legality seems at issue really uin my mind.

Quote, originally posted by Probot »

AMEN - however, i say expletive chicks too..literally. Never turn down moose knuckle.

All these posts and the OP NEVER stated the year.

FWIW..... Freeze12 is S N A P approved as an R-12 replacement