Air Con Compressor clicking on/off

[saleen836]

As title, my '06 has done it since I have owned it (close to 19 years) when idling, quite a few other 05-09 owners here in the UK have also said theirs does the same, some have commented stating the system needs re-gassing, I had mine regassed and it made no difference, is this a generic trait or is there something else going on?

 

[rocknrod]

This should help you, it's the Workshop Manual for the Climate Control Systems: http://iihs.net/fsm/?dir=336

 

[JC SSP]

First is the A/C working... is it cooling properly? Have you connected gauges to see high/low side readings?

It is Common for A/C compressors to cycle on/off. Now if it is doing fast and not really cooling especially in the middle of the day, then it could be low on freon. If its noisy well it's a part that wears internally.

 

[Autokyrios]

Could be a couple things but if the system is switching on then off again, the usual culprit is having not-enough or too-much of a charge in the AC system. When the climate control system calls for AC, the AC clutch turns on and the pump starts working. If the system doesn't detect the correct data from the sensors, it will switch back off. Unfortunately there's no flag in the system that says "if it failed, don't do it again."

I think there's also some logic for if the actual fan doesn't engage, but I could be imagining that one.

If it's been a while since you've had the AC refreshed, you're likely down on gas. Seals rot, etc. Although you can do the work yourself (with some special tools) it's just easier to take it to a shop and let them diagnose/fix.

 

[saleen836]

First is the A/C working... is it cooling properly? Have you connected gauges to see high/low side readings?

It is Common for A/C compressors to cycle on/off. Now if it is doing fast and not really cooling especially in the middle of the day, then it could be low on freon. If its noisy well it's a part that wears internally.

Yes, my aircon works perfectly and always blows cold, it is the air con clutch that operates for approx 5-10secs then cycles off, most noticeable when car is in the shop for it's yearly road worthyness test as the car idles while they check emmisions

 

[86GT351]

Yes, my aircon works perfectly and always blows cold, it is the air con clutch that operates for approx 5-10secs then cycles off, most noticeable when car is in the shop for it's yearly road worthyness test as the car idles while they check emmisions

If you are saying it blows cold and you are only experiencing the concern when idling, that is not so much of a concern. Pressures vary in an AC system under load. That is based on air flow through the front of the vehicle going across the condenser.

As the Airflow goes through the condenser it assists in the system breaking the Freon down from a High Pressure Liquid into a Low pressure gas. It does this because when it goes through the expansion valve it changes the Freon to a mist. Imagine a bottle of cleaner. Clearly a liquid, however when sprayed it comes out as a mist. This helps the system remove the heat and humidity out of the cabin of the vehicle allowing it to feel cooler.

Ultimately you can change out the compressor or clutch assembly and have the same result. If this is happening while driving the you have more to investigate.

 

[saleen836]

If you are saying it blows cold and you are only experiencing the concern when idling, that is not so much of a concern. Pressures vary in an AC system under load. That is based on air flow through the front of the vehicle going across the condenser.

As the Airflow goes through the condenser it assists in the system breaking the Freon down from a High Pressure Liquid into a Low pressure gas. It does this because when it goes through the expansion valve it changes the Freon to a mist. Imagine a bottle of cleaner. Clearly a liquid, however when sprayed it comes out as a mist. This helps the system remove the heat and humidity out of the cabin of the vehicle allowing it to feel cooler.

Ultimately you can change out the compressor or clutch assembly and have the same result. If this is happening while driving the you have more to investigate.

View attachment 104532

Thankyou, very helpfull info

 

[86GT351]

Thankyou, very helpfull info

You are welcome!