Intermittent AC

[greasegunn]

My 2010 Honda Civic with 98,000 miles is having an intermittent AC issue. The AC will work fine for approximately 20 minutes and then it stops. It seems to work longer in cooler weather and shorter in hotter weather. Once it has been parked awhile it will work again. Some investigating on the internet indicates it may be a worn compressor clutch and the repair is fairly straightforward. The issue that I’m trying to resolve in my mind is why it is intermittent? Why does the AC work initially and then stop? If the clutch is worn why does it work at all?

 

[CharBaby]

Check out this site. It's quick, you can skip ahead, and I have used this exact repair on the Mazda3 in my signature. Worked great! https://www.youtube.com/watch?v=DNx0X4INfiw

 

[SHOZ]

I've seen the clutch gap increase on high mileage cars and the AC quit engaging one they get hot. I've also seen the evaporator freeze up in hot weather and do exactly what you describe.

 

[HerrStig]

Originally Posted By: SHOZ

I've seen the clutch gap increase on high mileage cars and the AC quit engaging one they get hot. I've also seen the evaporator freeze up in hot weather and do exactly what you describe.

Evap freezing can be caused by a low charge level.

 

[mk378]

To diagnose, drive until it stops working then pull over (leave the engine and A/C switch on) and check whether the clutch is engaged or not. If you have freeze-up there will likely be ice on the line from the evaporator to the compressor. The clutch is based on an electromagnet. As the magnet coil gets hotter, its magnetic output decreases slightly. This will cause a clutch that is a little too wide to stop engaging, though it works when cold.

 

[SHOZ]

Originally Posted By: HerrStig

Originally Posted By: SHOZ

I've seen the clutch gap increase on high mileage cars and the AC quit engaging one they get hot. I've also seen the evaporator freeze up in hot weather and do exactly what you describe.

Evap freezing can be caused by a low charge level.

Or bad thermistors on the evap coil.

 

[DBMaster]

Originally Posted By: SHOZ

I've seen the clutch gap increase on high mileage cars and the AC quit engaging one they get hot. I've also seen the evaporator freeze up in hot weather and do exactly what you describe.

My 89 Accord did exactly that after about 100,000 miles. I could tell the clutch was energizing because a wrench would easily be held on the front of it due to the magnetism. I was unable to get the shim adjustment done because the shaft seal already had a slow leak so I ended up replacing the compressor. That car went through compressors every 100,000 miles like clockwork.

 

[Chris142]

Could be many things. Clutch gap,clutch coil,relay,expansion valve etc. Is the clutch still locked when it stops working?

 

[i_hate_autofraud]

Don't forget to look at the pressure limit switches, too low, it stops, too high it stops too!

 

[HoosierJeeper]

Sounds like a clutch issue. I doubt anything would be freezing up in that short amount of time. I'd pop the hood next time it stops and see what the clutch is doing.

 

[JMJNet]

If the AC Clutch is about to seize, you will hear screeching noise every time the AC is turned on. In my 04 Sienna, it was running like that for about 6 months. Then it completely seized. At that point, it is not worth to just fixing the clutch because the price of new compressor is only marginally more than the price of just the clutch like $20-$30 difference. Trouble is, you have to replace the condenser also since the new condenser cannot be flushed anymore, either.