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Old 9th July 2012, 02:11   #1
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Default Air-con problem after some time of operation

Vehicle: 2007 CRV.

Outside temperatures are pretty high these days ( 37 - 40 degree Celsius). Observed that AC stops cooling couple of times in the last 2 weeks. It happens when the AC has been running for some times in the coldest possible setting. I could feel that the AC stops cooling from the smell of the air and from increase in inside temperature.

When AC is running it is able to cool the car well. The compressor will be running even if it is not cooling (as observed from the sound and rpm meter). But once cooling is stopped, then switching AC off/on will not get the cooling back.
The best way to get the cooling back is to keep it switched off for a long period of time ( 30-45 mts).

Any idea what could be the problem?
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Old 9th July 2012, 07:07   #2
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Default re: Air-con problem after some time of operation

^^ your compressor clutch coil(the one which gets magnetised) has gone weak.It is not able to handle the load of the ac at low temperature settings

Temporary solution is to keep the temperature at 24deg.C and blower speed at minimum and "manage" till you get it fixed
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Old 9th July 2012, 11:19   #3
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Default re: Air-con problem after some time of operation

It could also be low pressure in the system. As soon as the gas pressure goes below a point, the compressor is cut off. This safety feature is almost universal now.
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Old 9th July 2012, 11:42   #4
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Default re: Air-con problem after some time of operation

Quote:
Originally Posted by vigsom View Post
^^ your compressor clutch coil(the one which gets magnetised) has gone weak.It is not able to handle the load of the ac at low temperature settings
vigsom, I think the load is same irrespective of the temperature. Temperature is controlled by the duration for which the compressor is ON. ie, if 18 degrees is needed, the compressor in ON for a longer time. Unless if its a Variable Displacement Compressor.

arjithin, how is the cooling when you move at fast speeds, and when you are in standstill traffic.

I think the reason is low gas in the system.
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Old 9th July 2012, 11:52   #5
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Default re: Air-con problem after some time of operation

Quote:
Originally Posted by arjithin View Post
Vehicle: 2007 CRV.

The compressor will be running even if it is not cooling (as observed from the sound and rpm meter). But once cooling is stopped, then switching AC off/on will not get the cooling back.
If compressor is ON with no cooling, can there be ice accumulation on your evaporator? Does your blower air flow (not the blower sound) reduces when you feel that the cooling is low? i believe, if there is low pressure, then cooling will be very less any time.
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Old 9th July 2012, 12:35   #6
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Default re: Air-con problem after some time of operation

Quote:
Originally Posted by arjithin View Post
When AC is running it is able to cool the car well. The compressor will be running even if it is not cooling (as observed from the sound and rpm meter). But once cooling is stopped, then switching AC off/on will not get the cooling back.

The best way to get the cooling back is to keep it switched off for a long period of time ( 30-45 mts).

Any idea what could be the problem?
I believe it could be either

a) Ice formation on the heat exchanger (a hint is the cooling is back after a period of time, so the ice melts or reduces)
b) Low gas pressure

One thing you can do is check that intake vents near the windshield are not blocked by leaves and other miscellaneous debris.

You need to get the AC system checked by a technician

PS - Also check if the cabin filter is blocked

Last edited by R2D2 : 9th July 2012 at 12:37. Reason: added PS
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Old 9th July 2012, 16:27   #7
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Default re: Air-con problem after some time of operation

Thank you every one for suggesting the potential reasons. I am taking my vehicle to the dealer in this week.
Quote:
Originally Posted by dhanushs View Post
arjithin, how is the cooling when you move at fast speeds, and when you are in standstill traffic.
Cooling is same irrespective of the speed of vehicle. When it cools, it does well.

Quote:
Originally Posted by ameaa View Post
Does your blower air flow (not the blower sound) reduces when you feel that the cooling is low? i believe, if there is low pressure, then cooling will be very less any time.
No I havent observed reduced airflow when the cooling is off. I too was thinking that if the gas pressure is low, then the symptom is overall cooling is less and not shutting off after some time.

Quote:
Originally Posted by R2D2 View Post
I believe it could be either

a) Ice formation on the heat exchanger (a hint is the cooling is back after a period of time, so the ice melts or reduces)
This could be the reason..but can ice be there outside when the temperature outside is 37-40?
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Old 9th July 2012, 17:20   #8
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Default re: Air-con problem after some time of operation

Quote:
Originally Posted by arjithin View Post
I too was thinking that if the gas pressure is low, then the symptom is overall cooling is less and not shutting off after some time.
IMO, What happens when the gas is low is, the compressor cycling switch turns off the compressor frequently, as there will be lower pressure of gas on the low pressure side of the evaporator frequently. Whenever the pressure is normal, the AC should work just fine.
Quote:
This could be the reason..but can ice be there outside when the temperature outside is 37-40?
If Ice formation is the reason, then your AC cut off should happen only after extended period of driving with AC ON in the lowest setting continuously.

The ice formation is due to a faulty compressor cycling switch, which fails to switch off the compressor below a certain pressure to prevent icing.
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Old 9th July 2012, 17:28   #9
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Default re: Air-con problem after some time of operation

Quote:
Originally Posted by arjithin View Post
This could be the reason..but can ice be there outside when the temperature outside is 37-40?


As a first step, I hope you were able to check for leaves/twigs blocking the external vents AND the cabin filter.

I refer to the heat exchanger/radiator inside the cabin..over which the blower circulates air in either Closed/Recirculate or Fresh Air mode.

Also forgot to mention previously earlier that the compressor lubricant is mixed with the gas and the gas is the carrying 'agent'.

So, if the gas pressure is low due to a leak or blockage in the system, the compressor may face lack of proper lubrication forcing it to shut down till the internal temperature falls. It will restart after the internal (compressor) temperature is back to normal. Needless to say operating the AC in this state will severely damage the compressor, a part that is pretty expensive to repair & costs even more to replace.

Please take the car to a competent AC technician ASAP.
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Old 9th July 2012, 21:03   #10
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Default re: Air-con problem after some time of operation

I would recommend taking it to a technician ASAP.
In my opinion it could be a fuse for the cooling fan in the engine bay. (happened in a friend's car..almost the same problem as yours). So you could check the fuses.
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Old 9th July 2012, 21:48   #11
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Default re: Air-con problem after some time of operation

Quote:
Originally Posted by agambhandari View Post
In my opinion it could be a fuse for the cooling fan in the engine bay. (happened in a friend's car..almost the same problem as yours). So you could check the fuses.
I don't believe it is a fuse. A blown fan fuse would mean the AC will have very low cooling effectiveness. However, in this particular instance, cooling resumes after a break of 30-45 mins.

Many cars have a common fan for engine radiator cooling and the AC radiator. The fan pulls in cool air from outside that passes over the engine and AC rads. A blown fuse can also lead to higher engine temps especially in stop and go traffic. Running an AC with an inoperative fan will increase the engine temps and further reduce AC effectiveness.
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Old 10th July 2012, 22:25   #12
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Default re: Air-con problem after some time of operation

I am facing identical problem in our Xylo E8 ABS too.
Our Xylo has Two AC Power Buttons- Lo Power and Hi Power.
When the AC is run on Lo Power the Cabin Temp. does not drop below 24-25 Deg C (Fan Speed at 3-4). If there are more passengers (may be more than 3-4), this 24 Deg does not help in afternoons. Also the Fan Speed at 3-4 is disturbing. So I am forced to use Hi Power which helps the cabin temp to drop to 19-20 Deg (Blower Speed 1).

Around 10 Kkms ago, I got the AC Cooling Coil (inside the dashboard) cleaned with Air and water but it did not help. I have cleaned the AC Cabin Filter also but still the problem persists.

What should I check for?

EDIT: -
Quote:
Originally Posted by arjithin
When AC is running it is able to cool the car well. The compressor will be running even if it is not cooling (as observed from the sound and rpm meter). But once cooling is stopped, then switching AC off/on will not get the cooling back.
Same is happening with our Xylo too.
Quote:
Originally Posted by arjithin
The best way to get the cooling back is to keep it switched off for a long period of time (30-45 mts).
I did not check what is the duration in our case.

Last edited by IndigoXLGrandDi : 10th July 2012 at 22:29.
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Old 11th July 2012, 14:12   #13
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Default re: Air-con problem after some time of operation

Quote:
Originally Posted by IndigoXLGrandDi View Post
What should I check for?
The lo and hi power switches only change the blower speed. That switch does not affect compressor operation.

Since you have had the cooling coils cleaned also have the AC refrigerant/gas pressure checked.
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Old 11th July 2012, 17:01   #14
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Default re: Air-con problem after some time of operation

The Lo Power and Hi Power Switches are different than the Blower Speed Knob.
The Blower Speed Knob has four speeds.
So I guess, when the Hi Power Switch is pressed, the AC Compressor uses more AC gas than that of when the Lo Power Switch is pressed.

Also, at the time of cleaning of AC Coil, the mechanic had disassembled everything and reassembled.
The details are available here
http://www.team-bhp.com/forum/techni...ml#post2725726 (A/c Evaporator coil fails 2nd time in my Ford Fiesta)

After that, he refilled the AC gas but still the problem is present.

I forgot to mention that when the ambient temp is less (evening or night), the Cabin Temp drops to 19-20 Deg (as compared to 24-25 in the afternoon) even if the Lo Power Switch is pressed.
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Old 11th July 2012, 17:16   #15
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Default re: Air-con problem after some time of operation

Quote:
Originally Posted by IndigoXLGrandDi View Post
After that, he refilled the AC gas but still the problem is present..
I haven't heard of a low/high power switch affecting the operational parameters of an AC compressor directly, but I am not very knowledgeable about the Xylo. Is it that it starts the 'surround AC'? That would mean circulating cool air thru other ducts to help cool the car faster

Assuming everything is ok and has checked out fine including the evaporator/compressor/etc has the system been checked for leaks recently by a competent technician?

If everything HAS checked out ok that would imply the AC system is probably operating at normal parameters..unfortunately they don't meet your expectations.

Quote:
Originally Posted by IndigoXLGrandDi View Post
I forgot to mention that when the ambient temp is less (evening or night), the Cabin Temp drops to 19-20 Deg (as compared to 24-25 in the afternoon) even if the Lo Power Switch is pressed.
That would be quite natural. All ACs work better when ambient heat is low.

Last edited by R2D2 : 11th July 2012 at 17:19.
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