A/C is one of the things I am certified in, and teach.

Don't flush the system. The only time it need flushed is if the system failed and spread particle contaminates through the system. Drain and evacuate the system to remove all gas contaminates. R134a is a smaller particle than R12. The smaller particle can leak through hoses and o-rings make to hold R12. This is why you change the o-rings. Luckly, the oil and residue from years of operation cause a film barrier to build on the inside of the system, holding the R134a. If you flush the system, you lose the barrier, and it is more likely to leak. This could cause you to need to change every rubber part in the system, o-rings, hoses, seals. All of the new parts are made to hold R134a. New old stock parts are not designed to hold R134a. The good news is you can use a sealer and not replace the parts. Sealer won't stop some leaks, and a repair may be necessary. Install new fittings for R134a, the correct type oil, and charge the system.

R134a works at a higher pressure than R12, but the system won't change pressure by doing change over. You will loose some efficency. Usually 5 to 10% loss. Most people will never notice this, and be very happy with the conversion. Our C3s have a small cabin, and the chances of you noticing are very slight.

To maintain maximum operation you would change the restriction valve or orifice, and the pressure switches. When I changed my Celebrity, I didn't do all this, and I'm happy with it.

Before adding any freon, the system must be evacuated to remove all air and moisture for it to operate correctly. Other than a vacuum pump and gauges, the AutoZone kit has what you need.

Don't use any other refrigent. It can be harmfull to the system, or to you. Some work well but are very dangerous in an accident. Posionous and/or explosive.

Ken Styer

|UPDATED|2/18/2004 8:31:54 AM (AZT)|/UPDATED|