# 97 Altima A/C Compressor Cycles



## Randallforty (Aug 28, 2005)

My A/C compressor is cycling ( has a clicking noise) on and off when hot and humid. Puts a drag on the acceleration. I just re-charged the freon. Does anyone have a clue??


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## erik2282 (May 17, 2005)

well a slight drag in acceleration is normal when the a/c is on, cuz it's belt driven. do u mean like a lot of drag?


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## Matt93SE (Sep 17, 2003)

they are also supposed to cycle on and off like that. usually it's about 30 sec at a time, but they will cycle.


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## 1996Altima (Sep 1, 2005)

Well, I can tell you that constant short cycling of the compressor will lead to premature failure. (I'm a certified HVAC tech in case you were wondering!) 
There could be a number of different reasons for the short cycle problem, one of which is often a loose connection but seldom is it caused by low refridgerant conditions. But, without seeing and hearing it first hand it would be difficult to diagnose your problem. Car A/C's do cycle more often then other A/C units but too much can mean costly repairs, I would advise taking it to a qualified mechanic.

Note: You may want to check the evaporator coil to make sure it isn't dirty. And avoid using the A/C in low load conditions, ( cooler weather ).


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## jserrano (Oct 27, 2004)

There is a temperature sensor called a thermistor outside the evaporator coil the feeds back the temperature to a Thermo Control Amplifier. That in turn tells the AC controller to turn the A/C clutch ON and OFF. If it is a flaw in this sensing unit then you'd have to take it to a qualified person who understands the system to check it out and fix it.

However, I am more inclined to believe something with the A/C charge of the system is giving you the problem.


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## vadeltachi (Jul 3, 2006)

1996Altima said:


> Well, I can tell you that constant short cycling of the compressor will lead to premature failure. (I'm a certified HVAC tech in case you were wondering!)
> There could be a number of different reasons for the short cycle problem, one of which is often a loose connection but seldom is it caused by low refridgerant conditions. But, without seeing and hearing it first hand it would be difficult to diagnose your problem. Car A/C's do cycle more often then other A/C units but too much can mean costly repairs, I would advise taking it to a qualified mechanic.
> 
> Note: You may want to check the evaporator coil to make sure it isn't dirty. And avoid using the A/C in low load conditions, ( cooler weather ).


I have a 97 maxima and the a/c seems to work well, but the compressor never cycles off. Is that normal? Does it affect fuel economy?


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## erik2282 (May 17, 2005)

vadeltachi said:


> I have a 97 maxima and the a/c seems to work well, but the compressor never cycles off. Is that normal? Does it affect fuel economy?


are you sure it doesn't cycle off? how do you know it doesn't? well it's supposed to. yes it will hurt fuel economy, probably not a whole lot but some...


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## LONDONDERRY (May 19, 2004)

jserrano said:


> There is a temperature sensor called a thermistor outside the evaporator coil the feeds back the temperature to a Thermo Control Amplifier. That in turn tells the AC controller to turn the A/C clutch ON and OFF. If it is a flaw in this sensing unit then you'd have to take it to a qualified person who understands the system to check it out and fix it.
> 
> However, I am more inclined to believe something with the A/C charge of the system is giving you the problem.



Does this thermistor sensor effect the car idle?


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## vadeltachi (Jul 3, 2006)

erik2282 said:


> are you sure it doesn't cycle off? how do you know it doesn't? well it's supposed to. yes it will hurt fuel economy, probably not a whole lot but some...


I've watched and listened to the compressor; unlike most other cars, I neither hear nor see any evidence of cycling (at least at idle). When I am actually driving, I notice no changes in idle speed or power changes. In my wife's car, both the fans and compressor cycle during idle, and it's possible to hear the fans start and stop as the compressor cycles.

The temperature is cool and comfortable, but there seems to be a slight hesitation in cooling when the a/c is first turned on (even though the compressor is engaged) that I don't recall when the car was newer.

What could possibly cause the compressor to cool correctly, but stop cycling?


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## Naijaboy (Oct 7, 2005)

If it doesnt cycle, you'll know.
At a certain point the cooling will decline significantly.
You'll feel the cooling at the vents but not actually in the car.This is due to the hoses freezing which is why the thermosistor cycles the compressor on/off to prevent overcooling of the hoses.


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## RAmiroperez79 (Jun 28, 2015)

*2005 Nissan Altima*

I have just replaced my compressor in a 2005 Nissan Altima after last one was shot. I filled it with Pac 46 liquid oil ,installed it,turned the engine over and filled it with freon. The problem I see is that the clutch will not cycle how it should. I read the previous forum yet cannot find anything on a A/C thermostat..


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