Post by Rotorhog on Aug 13, 2006 10:45:35 GMT -5
Man, this 1st gen section is looking left for dead! Anyway this is a procedure I posted over on Mazspeed.com to remove and replace an evaporator coil and expansion valve on a 1984 RX-7 GSL SE. I'ts probably the same for an '85. I can't vouch for the 79 - 83 years, never done one of those. Good info to have if you're trying to revive your AC system.
First, disconnect the battery! Then, get some sandwich zip lock bags to put all the screws and pieces in. Be sure to buy new o rings to replace the used ones when you reassemble the system. NOTE: This procedure is for the Nippon Denso AC system, NOT the Wynns AC system. See Kevin Wrights web page for Mazda parts manual drawings of the AC components.
Proceed at your own risk, the usual internet disclaimer applies to the following, I make no warranties or claims about the following information. OK, go fix your car now.
[1] Remove the cruise actuator, windshield wash tank, charcoal canister and cold start assist tank to get adequate access to the suction / discharge line fittings at the firewall. (If you have offset / angled wrenches removal of these items may not be required. NOTE: WEAR EYE PROTECTION - ANY PRESSURE IN THE AC SYSTEM WILL CAUSE OIL AND GAS TO SPRAY OUT, POSSIBLY INTO YOUR EYES!) Plug the ends of the suction / discharge lines to prevent foreign object entry into the system.
[2]. Remove the dash trim plate on the end of the dash by the passenger door (2 screws).
[3] Remove the carpeted trim plate at the console (2 screws).
[4] Remove the glove box. This requires removing the latch plate (2 screws) and the light fixture and the light bulb from it. There are 3 screws across the bottom of the assembly to remove after the door flops open and 2 on the either side of the black felt covered frame at the top. It won't come out until you get all of the above. After all the screws are out you can pull the assembly out a bit to better access the light fixture and bulb for removal.
[5] Remove actuating knob from the vent lever (pulls straight off) to remove the dash trim plate below the glove box, again 2 screws here also. Be gentle with it, old plastic you know. Gently pry back the wire harness mounts to free it from the dash trim plate.
[6] Remove the black AC / vent duct. there will be 2 metal clips on the front that must be unscrewed to remove the duct. The screw is mounted vertically on each clip to free the duct from the dash structural piece.
[7] Remove the push pin from the lower end of the white AC / defroster duct. Pull it out at the bottom. You can leave the top connected and just move it aside when pulling out the evaporator assy.
[8] Remove the 2 wire leads from the thermostat on the upper left portion of the evaporator box. DO NOT remove the 2 mounting screws that attach the t'stat to the evaoporator housing just yet. On my 84 SE the blue wire is the closest lead to you, the yellow is to the back. Be sure to remember which goes where on your car if the colors are different. BTW - this is the thermostat that the TSB says to adjust to increase compressor cycle time for more cooling. I just can't remember which way to turn the adjustment screw. The adjustment is minimal, less than 1/4 turn or the coil may freeze up.
[9] Disconnect the AC condensate drain line from the pipe on the bottom of the evaporator housing by gently pulling it off.
[10] There are plastic retaining clips on top of the housing that secure a wiring harness in place. They glow in the dark, no excrement. I could not get them apart to remove the harness so I cut the clips to free the harness. Maybe someone else knows how they come apart.
[11] On either side of the evaporator housing are two metal bands that secure the inlet side of the housing from the blower assembly and the outlet side to the ducts behind the center console. Back off the retaining screw and slide them away from the housing. At one time these were foam lined but that foam has turned to dust. I removed the bands and glued felt to mine to restore the seal and prevent air leaks.
[12] Place an old towel under the evaporator housing to catch any oil that may drip from the lines when pulling the housing out. Remove the nut from the mounting bolt at the top of the evaporator housing and at the bottom. Carefully pull the housing straight back to clear the lines through the firewall and remove the evaporator housing.
[13] To seperate the upper and lower halves of the evaporator housing, carefully pry the metal clips off the housing with a flat blade screwdriver. Then, remove the 2 mounting screws that secure the t'stat to the upper housing. Be careful not to bend or damage the tube that runs into the coil itself.
[14] At this point carefully remove the coil assembly from the lower housing. Blow out the coil with compressed air if possible then plug the ends of the lines to prevent foreign object entry into the coil or AC system. It is highly recomended that the coils should be cleaned to remove the 20+ years of crap and film that interferes with heat / cold transfer. Talk to your local AC technician about what product to use that will safely clean the coils. This will help efficiency and air flow through the system. There are no cabin filters on these cars and the evaporator coil is the crud catcher in the system. Cleaning led to a noticeable improvement in air flow for me upon reassembly.
[15]Carefully remove the old expansion valve and install a new one. I got mine from O'Reillys Auto parts. It was a little bigger than stock but worked fine. Be sure to install the new o rings (lube them before installation) and align the inlet pipe to the expansion valve below the suction line so it will mate up through the firewall on reassembly.
[16] Reassemby and reinstallation is reverse of the above.
I did this entire process and had it finished in 6 hours. I took my time so I didn't make a bigger mess than I hoped to fix. Your results may vary.
We pulled a vacumn on it and charged to approximately *2.25 lbs of r134a. On a 88 degf day we go 40 degf at the center outlet on max AC recirc while idling. The head pressures were 35 lbs suction, 200lbs discharge. Going down the road I saw 37 degf. One morning on the way to work it actually got to 35 degf. Of course, it was on 67 degf that morning.
*Since I have found data that indicates a full charge on an RX-7 AC in the days of R12 was 1.5 to 1.7 lbs. I have since trimmed the charge to get in line with that data. It has made a noticeable decrease in AC performance at traffic lights on hot days, but still drops to 42 - 44 degf when moving.
First, disconnect the battery! Then, get some sandwich zip lock bags to put all the screws and pieces in. Be sure to buy new o rings to replace the used ones when you reassemble the system. NOTE: This procedure is for the Nippon Denso AC system, NOT the Wynns AC system. See Kevin Wrights web page for Mazda parts manual drawings of the AC components.
Proceed at your own risk, the usual internet disclaimer applies to the following, I make no warranties or claims about the following information. OK, go fix your car now.
[1] Remove the cruise actuator, windshield wash tank, charcoal canister and cold start assist tank to get adequate access to the suction / discharge line fittings at the firewall. (If you have offset / angled wrenches removal of these items may not be required. NOTE: WEAR EYE PROTECTION - ANY PRESSURE IN THE AC SYSTEM WILL CAUSE OIL AND GAS TO SPRAY OUT, POSSIBLY INTO YOUR EYES!) Plug the ends of the suction / discharge lines to prevent foreign object entry into the system.
[2]. Remove the dash trim plate on the end of the dash by the passenger door (2 screws).
[3] Remove the carpeted trim plate at the console (2 screws).
[4] Remove the glove box. This requires removing the latch plate (2 screws) and the light fixture and the light bulb from it. There are 3 screws across the bottom of the assembly to remove after the door flops open and 2 on the either side of the black felt covered frame at the top. It won't come out until you get all of the above. After all the screws are out you can pull the assembly out a bit to better access the light fixture and bulb for removal.
[5] Remove actuating knob from the vent lever (pulls straight off) to remove the dash trim plate below the glove box, again 2 screws here also. Be gentle with it, old plastic you know. Gently pry back the wire harness mounts to free it from the dash trim plate.
[6] Remove the black AC / vent duct. there will be 2 metal clips on the front that must be unscrewed to remove the duct. The screw is mounted vertically on each clip to free the duct from the dash structural piece.
[7] Remove the push pin from the lower end of the white AC / defroster duct. Pull it out at the bottom. You can leave the top connected and just move it aside when pulling out the evaporator assy.
[8] Remove the 2 wire leads from the thermostat on the upper left portion of the evaporator box. DO NOT remove the 2 mounting screws that attach the t'stat to the evaoporator housing just yet. On my 84 SE the blue wire is the closest lead to you, the yellow is to the back. Be sure to remember which goes where on your car if the colors are different. BTW - this is the thermostat that the TSB says to adjust to increase compressor cycle time for more cooling. I just can't remember which way to turn the adjustment screw. The adjustment is minimal, less than 1/4 turn or the coil may freeze up.
[9] Disconnect the AC condensate drain line from the pipe on the bottom of the evaporator housing by gently pulling it off.
[10] There are plastic retaining clips on top of the housing that secure a wiring harness in place. They glow in the dark, no excrement. I could not get them apart to remove the harness so I cut the clips to free the harness. Maybe someone else knows how they come apart.
[11] On either side of the evaporator housing are two metal bands that secure the inlet side of the housing from the blower assembly and the outlet side to the ducts behind the center console. Back off the retaining screw and slide them away from the housing. At one time these were foam lined but that foam has turned to dust. I removed the bands and glued felt to mine to restore the seal and prevent air leaks.
[12] Place an old towel under the evaporator housing to catch any oil that may drip from the lines when pulling the housing out. Remove the nut from the mounting bolt at the top of the evaporator housing and at the bottom. Carefully pull the housing straight back to clear the lines through the firewall and remove the evaporator housing.
[13] To seperate the upper and lower halves of the evaporator housing, carefully pry the metal clips off the housing with a flat blade screwdriver. Then, remove the 2 mounting screws that secure the t'stat to the upper housing. Be careful not to bend or damage the tube that runs into the coil itself.
[14] At this point carefully remove the coil assembly from the lower housing. Blow out the coil with compressed air if possible then plug the ends of the lines to prevent foreign object entry into the coil or AC system. It is highly recomended that the coils should be cleaned to remove the 20+ years of crap and film that interferes with heat / cold transfer. Talk to your local AC technician about what product to use that will safely clean the coils. This will help efficiency and air flow through the system. There are no cabin filters on these cars and the evaporator coil is the crud catcher in the system. Cleaning led to a noticeable improvement in air flow for me upon reassembly.
[15]Carefully remove the old expansion valve and install a new one. I got mine from O'Reillys Auto parts. It was a little bigger than stock but worked fine. Be sure to install the new o rings (lube them before installation) and align the inlet pipe to the expansion valve below the suction line so it will mate up through the firewall on reassembly.
[16] Reassemby and reinstallation is reverse of the above.
I did this entire process and had it finished in 6 hours. I took my time so I didn't make a bigger mess than I hoped to fix. Your results may vary.
We pulled a vacumn on it and charged to approximately *2.25 lbs of r134a. On a 88 degf day we go 40 degf at the center outlet on max AC recirc while idling. The head pressures were 35 lbs suction, 200lbs discharge. Going down the road I saw 37 degf. One morning on the way to work it actually got to 35 degf. Of course, it was on 67 degf that morning.
*Since I have found data that indicates a full charge on an RX-7 AC in the days of R12 was 1.5 to 1.7 lbs. I have since trimmed the charge to get in line with that data. It has made a noticeable decrease in AC performance at traffic lights on hot days, but still drops to 42 - 44 degf when moving.
