RX7Foxx

Since I bought my 86 rex I've had a persitant problem with the A/C. The cluctch on the compressor engages and I get moderatly cold air for about 5 minutes or so then the clutch seems to disengage by itself. From that point on I get VERY hot air blowing through the vents even though the blower is off.

If I wait about 20 mintues I can use the A/C but the same cycle continues, it runs for about 5 minutes then shuts off. I know the R-12 is low, I checked the sight glass and it's all foamy in there. However, when I called my local Mazda dealer he said it sounds like the Logicon is bad, and that would run me about $500-$600 plus another $150 to recharge the system. Far too much to get A/C, I would rather put 16" rims on my rex for that.

When I bought the car the previous owner mentioned something about a line leak and a bad expantion and compression valve, whatever that is, and it would cost me about $500 to fix. Now I do not think the Logicon itself is bad because everything else works on it, the little directional doors buzz and open and all that. But maybe I could be wrong. Has anybody else had this problem?

IHookItUuup

You can check to see if the compressor is not engaging by hooking up a pressure manifold to the high and low side fittings on your a/c system and checking for adequate pressure when the system is blowing hot air. If the pressure is within range then the problem is the expansion valve. If not, then the problem is with the compressor or perhaps the coolant.

Icemark

Logicon will not control the cycle of the air conditioner, however it does control the air mix motor which controls the heat/cool ratio.

Next time it does it, check to see if the air mix motor is moving when you flip the temp setting on the logicon up or down. You should be able to hear a electrical motor moving in the dash by simply moving that temp setting.

If there is no movement, then it could be a bad Logicon. If there is movement it won't be.

Also remember that the air conditioning needs the accessory circuit form the ignition switch to be on, to activate the compressor. If you have intermittent radio power issues it could be just related to the key/ignition switch.

Either way, you'll need to fix the air conditioning if it has bubbles in the system. I would recommend and air conditioning shop, way before ever taking it to a Mazda dealer.

duffles

sounds like an air mix motor. i had this problem, it is shuting the door between the cool air and hot heater air. go to mazdaformance ad above, go to clearence parts, wait for them to show up and find a NEW air mix motor for only 69 bucks by far the cheapest new one out there. or ask around for used for less if someone wants to pull one for you, they are a bitch to remove/install. good luck

Johny zoom

iTrader: (5)

You answered your own question. Im not a RX guru but I know a little about A/C The clutch is engageing tells you logicon is OK It is Cycling because of low/ high pressure. R12 is very expensive there are now some drop in replacements * meaning you dont have to evacuate your system, change compressor oil *like you do for 134A, anyway a refrigerant R 414 called hot shot is available and can be put in on top of exsisting charge. Where you see the bubbles,on the accumulator there is a plug, unplug and put a jumper across the terminals plug side compresser should stay running now. Most people wouldnt recommend leaving it like this.