The evaporator P/N 54521 will be $79 at Advance Auto Parts.
Heater core replacement tech note:
Mustang
R134a Air Conditioner Conversion and recharge instructions
Tools and materials you will need:
R134a = $7-$10 a can – takes 2 - 2 ½ cans.
R134a compatible oil = $5-$7 for an 8 oz bottle – better get 2 bottles.
Gauge set for recharging = $20-$120 – check out the pawn shops for a bargain before you pay retail.
See
Harbor Freight Tools for an inexpensive gauge set.
Vacuum pump – I use an old refrigerator compressor = $20- $40 at used appliance stores, or go to the Dump and get one for free. Be sure to have some R12 compatible oil handy to keep it lubed up properly.
O ring seal kit = $8.
R134a charging can adapter = $13 (I cut mine up to use it with the R12 gauge set that I have had for a long time).
Plastic tools to disconnect refrigerant lines - 1/2" & 5/8" = $4 each.
Miscellaneous hoses and fittings to adapt the R134a adapter to the R12 gauge set = $15. If you buy an R134 gauge set you can skip this.
R134 Refrigerant charge is 26-28 Oz plus 6-8 Oz of PAG 100 oil.
Conversion Instructions:
Keep in mind that to fulfill the requirements of the EPA, you are required by law to recover any refrigerant that still remains in the system. How (or wither or not) you accomplish this is up to you. Connect the charging gauge hoses to the service ports on the A/C (red gauge = high pressure, blue gauge = low pressure) and open the valves on the gauges to dump the remaining refrigerant (if any) into your "freon recovery system", whatever it may be. Disconnect the charging gauges since you are finished with them until you are ready to fill the system with R134a.
Next comes the changing of all the old "O" rings so that the chances for leaks is minimized. Use the plastic connector tools to separate the lines, place the extended collar part of the tool so that it faces the large part of the connector and push inwards: this expands the spring so that you can pull the tube apart. You may need a helper to push on the tool while you pull on the tubes to separate them. Install the new "O" rings: be sure to coat them with new oil when you put them in. Install the new dryer/receiver, R134a service port adapter, compressor, add about more 4oz of oil to high pressure line and tighten up all the lines. Close the hood, start the engine, let everything get warm under the hood, but don’t add the R134a or turn the A/C on. Connect the charging gauge hoses to the service ports on the A/C (red gauge = high pressure, blue gauge = low pressure) and open both valves, then connect the center hose to the vacuum pump. The purpose of this exercise is to heat up the system so that when you vacuum it all down (yes, you will need a vacuum pump- mine is an old refrigerator compressor), that all the air, vapor and moisture from the cleaning fluid vaporizes and is removed from the system. Vacuum it down for about 30 minutes, this should give you about 28" of vacuum or more inside the A/C system. I have a vacuum gauge "T" connected into the vacuum pump line so that I can accurately watch the vacuuming process. This is a good time to take a soda and sandwich break since it doesn’t go faster if you watch it.
Typical low pressure side R134 coupling
Typical high pressure side R134 coupling
Charging instructions:
Remove the electrical connector from the dryer/receiver and jumper the two connections inside the wiring harness side of the connector together: this allows the compressor to engage in spite of low pressure/no gas in the system. Close both charging gauge valves, and then disconnect the center hose of the charging gauges from the vacuum pump and connect it to the R134a can tapper. Put the R134a can in the can tapper and screw it down with the can tapper valve closed, then open the valve. Loosen the hose at the center connection of the charging gauge set until the R134a squirts out: this purges the line of air and moisture. The refrigerant is added through the low pressure side of the system, so open the low pressure gauge valve to add the R134a. Start the car and take note of the idle speed, then set the idle speed up to about 1200-1500 rpm, and turn the A/C on inside and set the fan speed on high. Watch for the pressure on the low side to drop off as you are filling, and the R134a can will get warm and stay warm. This tells you the current can is empty and needs to be changed for a fresh one. Before you disconnect the can, be sure to close the valve on the R134a can tapper.
Watch the high side pressure on the charging gages and regulate the adding of gas to keep the high side pressure under 350 psi. You will probably need a fan in front of the car to keep the readings below 350 psi. I had to put the R134a can in hot water while I was charging the system with it, or else the can got so cold that it quit flowing. Use caution when you do this so that you don’t get water in the charging adapter when you change the cans. When you have added the 2 cans of gas, the high side will read about 250-300 psi and low side about 28-38 psi. Turn the idle speed back to where it was, turn the A/C off, disconnect the charging gauges, and re-install all the caps on the service ports. Remove the jumper from the low pressure switch harness and plug it back on the switch connectors.
The above technical note is for informational purposes only, and the end user is responsible for any damages or injury. The end user bears all responsibility for proper recovery/disposal of any R12 refrigerant.
This includes some of the parts that they already replaced 9 months ago, so we have some issues there, but the bulk of the bill is the Evaporator ($176.15) and the labor to RnR the Evaporator ($504.00). The full estimate has $396.47 in parts, $729.00 in labor, $25.00 in shop supplies (WTF? - is this for lunch for the guys?) and $80.53 in tax.
