2002 Honda Civic Intermittent cooling

Tiny
JSINNOTT
  • MEMBER
  • 2002 HONDA CIVIC
  • 4 CYL
  • FWD
  • MANUAL
  • 180,000 MILES
Hello, my mother's 2002 Honda Civic started having A/C problems about a month ago. Her A/C seems to work well on during highway driving but in city or stop and go driving the A/C only blows hot air. She took it to her local Honda dealer while experiencing the problem and after "checking everything out" they replaced the thermistor (charging her $450). This did not fix the problem so she brought the car back in and they tightened the loose connection to the thermistor. But this did not fix the problem either. She has been to the dealer 4 times now but is only $450 poorer to show for it. Does anyone have any ideas or suggestions for her? Thanks!
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Friday, August 7th, 2009 AT 10:46 PM

7 Replies

Tiny
KHLOW2008
  • EXPERT
Hi jsinnott,

Thank you for the donation.

I need to clarify this. You mentioned the AC is blowing HOT, is it hot as if the heater is being turned on or just that it is not cooling sufficiently?

If hot as if heater has been turned ON, the fault should be with the air mix door control circuit.

If it is not blowing cool sufficiently, it could be caused by inefficient condenser cooling. Check if the condenser fan is turning on when the AC compressor is engaged.
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Saturday, August 8th, 2009 AT 8:52 AM
Tiny
JSINNOTT
  • MEMBER
Thanks for the response KHLow2008. The air the a/c blows when it is not working is not heated, it is about the temperature of the outside air.

I just ran the following experiment:
1) Turned on the car
2) 2 large fans behind radiator and condenser were not on (I assume these are the condenser fans as I saw no other fans)
3) Turned on a/c which blew cold air and both fans came on and appeared to be working fine.

So do we need to check the fans when the a/c is not working or do you have another idea?

Thanks, James
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Saturday, August 8th, 2009 AT 9:00 PM
Tiny
KHLOW2008
  • EXPERT
Hi James,

Good job done. You have confirmed the fans are operating and the problem is not due to the heater system interfering so we can get to the diagnostics. Who knows, we might be able to show the dealer some tricks.

The 2 large fans are known as radiator and condenser cooling fans, with the radiator fan at the transmission side. They would only come on when the AC compressor is engaged or when the engine operating temperature is hot enough to activate the fan switch.

The main problem should be the compressor cutting out when vehicle is operating at low speed and there are a few possibilities.

1. Low engine idling speed.
What is the idling speed when engine is at operating temperature?
Is there any clicking noise from the engine and does the idling speed keeps fluctuating when it is happening?
You can check this when the AC starts blowing warmer air. Note if the AC switch green light is flickering for a start.

2. Weak compressor. The compressor is able to provide cooling only when it is turning at a higher engine speed and when slowing down or stopped, the engine speed is low thus the inefficient cooling.
To test this, when AC is not blowing cold, check if the compressor is engaged, visually inspect if the compressor clutch is engaged and note if the cooling fans are running.
If clutch is engaged and fans are running, increase the engine rpm to 2000 and note if the cooling efficiency is improved.
Did the dealer check the low and high pressure at idling and when rpm is increased to 2000 rpm? This test should be able to tell if the freon level is correct, any operational malfunctions and possble cloggings in the system.

3. Freon, lack of it or over filled. Lack of it would be the more likely cause as overfilling would have the compressor cutting in and out while driving as well and the cooling would not be good as well.

4. Inefficient condenser cooling. As fans are working, it could be the condenser fans sre clogged with mudm dirt etc so give it a viasual inspection to confirm this.

5. Electrical circuit or component malfunction. Test would have to be carried out and if you have a DVOM and is into DIY, we can assist in provding the procedures.

Check the above and if there are any information that you think can be of assistance, please let me know.

Was any repairs done prior to this happening?
When AC is not blowing cold, does it improve when the vehicle starts moving?
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Saturday, August 8th, 2009 AT 9:47 PM
Tiny
JSINNOTT
  • MEMBER
Thanks for the detailed response KHLow20080.

My mother drove back from NC to DC today (about 5 hours of highway driving unless there is a traffic jam) and had an update for me. This time while always at highway speed the a/c worked intermittently. She reported that it would work for maybe 1-2 hours and then start blowing ambient air temp (93 and humid today). She would turn it off and try it again in 10 min and it was still blowing ambient air temp. She would keep trying it every 10 min and after about 30 min or so it would start working again for the next hour or two. This pattern repeated for her entire 5 hour drive.

Regarding your other questions:

1. Looks like her lower end EX model does not have a tachometer. She hasn't noticed any significant idle speed variation, clicking while idling, or the AC switch green light flickering.

2. Since the a/c doesn't always work at high speed now I guess weak compressor is less likely. She is supposed to go to the dealer this week to complain so I will have her ask the dealer the questions you posed below and any others you care to suggest.

3. Maybe overfilling is more likely now that the a/c is curring out while driving as well?

4. The fans and condenser (what I could see through the grill) looked reasonably clean.

5. She took her car home so I probably won't be able to take this that far.

6. She said no recent repairs other than routine maintanence unrelated to a/c.

7. Per above the a/c does not work (at times) when the vehicle is moving. She also tried giving the car some gas while idling when the a/c was not working and it did not seem to have any effect.

8. I looked at the receipt from the dealer last night and they listed many tests they completed for about $350. I don't have the receipt now but can get the info from my mother if you think that would be useful.

Thanks, James
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Sunday, August 9th, 2009 AT 9:51 PM
Tiny
KHLOW2008
  • EXPERT
Hi James,

Based on the latest detailed description of the problem, the compressor is cycling on and off or is not working intermittently and possible causes are :

1. Excessive freon in system
2. Bad compressor clutch. A test of the funtionality of the clutch and its coil resistance would be required.
3. Bad PCM. The AC control circuit from the Power Control Module is bad. When AC cuts off, it sometimes requires some on/off operations to get it working.
4. Failing compressor clutch relay.

Let the dealer check on the above possiblities.
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Monday, August 10th, 2009 AT 8:29 AM
Tiny
JSINNOTT
  • MEMBER
I realized I never posted the final resolution to this problem. After my mother showed up armed with your questions the service manager ended up taking the car home for a few days to recreate the problem. When the problem happened he discovered the clutch on the compressor was out of tolerance. They fixed it by adding a shim to get it engaging again and it has been working fine ever since. Thanks for all of your help and ideas.

James
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Sunday, September 20th, 2009 AT 9:01 PM
Tiny
KHLOW2008
  • EXPERT
Hi James,

Thank you for the update. Glad to know that you have solved the problem.

Thank you for using 2carpros.
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Sunday, September 20th, 2009 AT 11:59 PM

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