Tuesday, July 7, 2009

Replacing a Honda Civic condenser fan without draining the freon

My 1992 Honda Civic recently developed a strange problem where the engine would idle badly and sometimes stall when the air conditioning was being used. Oddly enough, the problem turned out to be a non-functional condenser fan. Presumably, the compressor would pump the high side of the system up to an abnormally high pressure because the system was unable to dissipate heat from the condenser. Eventually the mechanical load from the compressor was so great it would cause the engine to stall. I would have guessed there was a high pressure limit switch that would deactivate the compressor, but maybe not.

In any case, this is an R12 system, and I did NOT want to open any of the freon lines. It had been working great ever since I bought the car (until this recent problem), and I did not want to mess with it. Luckily, it's possible and not too difficult to change the fan motor without opening the freon lines.
The fan shroud is bolted to the condenser with two 10mm bolts near the top facing into the condenser. There is also a small bracket on your left that has two 10mm bolts to hold the bracket to the condenser and shroud. I removed all four of these bolts, two bolts that held the shroud to the car's frame at the top, a bolt that holds a freon hose to the shroud, and also a bolt that holds a relay to the frame (on your right).



The shroud can be lifted up and out of two pockets that are formed into the metal of the condenser. It cannot be fully removed from the car because there is a freon hose in the way, and the hose cannot be moved. Instead, I removed the plastic rock guard on the underside of the car, and slipped the shroud out through the bottom. There are a few wire-guides and connectors on your right that need to be removed before the shroud will clear the car. I didn't even need to jack the car up.



Once the shroud (and fan) were out of the car, I switched the motor with the new one. Do NOT forget to also move the tiny washer from the old motor to the new one, which tends to stick to the old motor shaft and fits so tightly it almost looks like part of the shaft itself. I made this mistake and it nearly ruined my day. Without the washer in place, tightening the nut will cause the metal hub of the fan to be pushed in a bad way so that it is no longer engaged with the shaft. Since there is no other way to grab hold of the shaft, you are left with trying to get the nut back off and no way to stop the shaft from turning. After fiddling with it for a long time, I remembered my dad recommended the use of a pneumatic impact wrench in situations where a nut must be removed from a free-turning shaft. The idea is that the impact wrench hits the nut so hard and so fast, it is able to back it off while the inertia of the shaft holds the part still. Lo and behold, it zipped the nut right off. Thanks, dad!


The rest of the job was pretty straight-forward, and now my air conditioner works like a champ and doesn't stall the engine.

The old motor appears to have died of old age. There aren't any catastrophic problems, but the brushes and commutator show heavy wear. The motor case was full of carbon dust from the brushes.

3 comments:

  1. my civic 98 right now have the fan bad and I open the motor and have full of carbon and the brushes are very wear... I waiting to get a oem used fan from ebay... for 35 $... I don`t drain the freon gas but I remove the exhaust manifold and clutch slave cylinder to move out the fan...

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  2. My 1992 Civic had the same problem, I thought it might be low on Freon or the compressor was broken. I really didn't realize until now how important the condenser fan is to the a/c unit. The condenser fan on my car was actually running but it was going really slow, but it produced the same symptoms as your car had. I used your article to replace my fan motor and now all is well. Thanks for taking time to put this information on the Internet !!

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  3. I also have a 92 Civic with the same problem but after i took out the fan I thought it would be good to check to make sure it wasn't working by jumping it from the battery and it worked fine. So i thought i'd try putting back in and try it and it worked great...for a day. Now it's not working again. Is there a relay for it? I checked the fuse and it's good and saw the radiator cooling fan and a/c compressor relays but didn't see a relay labeled condensor.

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