Author Topic: Aircon failure.  (Read 502 times)

VicW

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Aircon failure.
« on: June 09, 2021, 04:01:22 PM »
It was bound to happen now we have some warm weather but my aircon has failed. It was OK the last time I drove the car but yesterday it would not cool the air right from start-up. It was serviced a couple of weeks ago and was fine before and after. The symptoms are:- On start-up the condensor cooling fan runs but the compressor isn't cutting in and out indicated by a lack of the slight fluctuation on the rev counter as is normal as the compressor cycles, the cooling fan runs all the time and doesn't cycle as is usual. Turn the aircon off and the condensor cooling fan stops. With the engine off but the key in the 'run' position switching the aircon on switches the fan on but you cannot hear the compressor clutch engaging.
My suspicion is that there is a gas leak and that the system is empty hence the compressor clutch will not engage. I say this because when I parked the car the time before the aircon failure I noticed a larger than normal pool of liquid under the engine, larger than is normal with the aircon in use so I suspect a condensor failure, the garage that did the aircon servicing use dye in the regas to detect leaks, I can't see any but I don't know if they use a light source to show the leaks up and I don't crawl under cars any more. The car is booked in for diagnosis next week, watch this space.

Vic.

culzean

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Re: Aircon failure.
« Reply #1 on: June 09, 2021, 04:19:21 PM »
It was bound to happen now we have some warm weather but my aircon has failed. It was OK the last time I drove the car but yesterday it would not cool the air right from start-up. It was serviced a couple of weeks ago and was fine before and after. The symptoms are:- On start-up the condensor cooling fan runs but the compressor isn't cutting in and out indicated by a lack of the slight fluctuation on the rev counter as is normal as the compressor cycles, the cooling fan runs all the time and doesn't cycle as is usual. Turn the aircon off and the condensor cooling fan stops. With the engine off but the key in the 'run' position switching the aircon on switches the fan on but you cannot hear the compressor clutch engaging.
My suspicion is that there is a gas leak and that the system is empty hence the compressor clutch will not engage. I say this because when I parked the car the time before the aircon failure I noticed a larger than normal pool of liquid under the engine, larger than is normal with the aircon in use so I suspect a condensor failure, the garage that did the aircon servicing use dye in the regas to detect leaks, I can't see any but I don't know if they use a light source to show the leaks up and I don't crawl under cars any more. The car is booked in for diagnosis next week, watch this space.

Vic.

Checking and putting more gas into the system may have caused the fill valve on 'low' or 'high' side to leak.... just like happens with tyres sometimes  :o

Also sometimes when the gas getting low in system it can cause the condenser to ice up ( goes into 'supercool' mode ) the system needs the correct amount of gas to control the expansion and compression of the gas,  so this balance gets upset shortly before system fails to have enough gas to trigger the pressure switch to allow compressor to run safely without damaging it.

This refers to domestic aircon,  but the principle is exactly the same.  I noticed the condensor on my de-humidifier starting to freeze up shortly before it stopped running due to a gas leak.....

The extra condensate under your car points to the condensor freezing and a lot more ice than usual melting off it ( in fact not even sure the condensor gets ice on it during normal running, there is a temperature sensor on there and when it gets down towards freezing it cycles the compressor to prevent it freezing up  )..

https://asm-air.com/airconditioning/air-conditioner-freezing-up/
« Last Edit: June 09, 2021, 06:47:47 PM by culzean »
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Rory

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Re: Aircon failure.
« Reply #2 on: June 09, 2021, 09:17:20 PM »
The extra condensate under your car points to the condensor freezing and a lot more ice than usual melting off it ( in fact not even sure the condensor gets ice on it during normal running, there is a temperature sensor on there and when it gets down towards freezing it cycles the compressor to prevent it freezing up  )..

It's the evaporator (inside the car) that freezes up. 

The clutch went on our 09 Jazz a couple of years ago.  Son-in-law has it and the garage fitted a used compressor.

MartinJG

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Re: Aircon failure.
« Reply #3 on: June 10, 2021, 03:06:46 AM »

Sounds like the Aircon people might have messed up the pressure. It shouldn't happen as most of them are now automatic but human error accounts for far too many cockups. The other alternative is that the condensor is just worn and the magnetic action is not functioning but that does seem highly unlikely. I go for geezer gremlins :)

culzean

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Re: Aircon failure.
« Reply #4 on: June 10, 2021, 07:18:50 AM »
The extra condensate under your car points to the condensor freezing and a lot more ice than usual melting off it ( in fact not even sure the condensor gets ice on it during normal running, there is a temperature sensor on there and when it gets down towards freezing it cycles the compressor to prevent it freezing up  )..

It's the evaporator (inside the car) that freezes up. 

The clutch went on our 09 Jazz a couple of years ago.  Son-in-law has it and the garage fitted a used compressor.

The water drains under the car from whatever cold bit is in the car HVAC system ( the bit that is gonna freeze up ) the other ( hot bit ) is in front of engine cooling radiator.   A/C clutch solenoid went on my Civic, whole clutch 50 from Ebay and replaced it myself,  been fine ever since.   For the aircon to run OK and then shortly after a 'service' fail with all the symptoms of low gas points to 'messing with things that ain't broke'... first rule of fault finding is 'look closely at whatever was messed with last'.........
« Last Edit: June 10, 2021, 08:33:27 AM by culzean »
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VicW

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Re: Aircon failure.
« Reply #5 on: June 10, 2021, 02:35:24 PM »
The symptoms that I originally reported have changed, probably my fault for noting them incorrectly in the first place. I said previously that the condenser fan was running all the time the AC was selected to on. Well it isn't now, it is not running at all, it should cycle with the compressor. The compressor doesn't have a visible clutch, later ones don't, but the end of the compressor is rotating. Another clue that I didn't notice before is that both condenser pipes are warm, not good, one should be cooler than the other. It points to a lack of gas pressure and hence probably a leak.
The AC was serviced three weeks ago and had been alright up until Tuesday so I don't suspect their competence, in fact they phoned me when they started on it that it was running cold enough and did I still want it done. I went ahead because it hadn't been for three years and it was possible that the lubricant included in the gas was getting a bit low.

Vic.

culzean

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Re: Aircon failure.
« Reply #6 on: June 10, 2021, 02:46:25 PM »
The compressor drive pulley is the lowest one of the two under the alternator pulley.  Be careful because the outside of the pulley runs all the time ( it has to because the belt is turning it ),  When the clutch solenoid is energised by the ECU it links the outside drive pulley with the centre portion of the pulley ( like 3 flat springs at 120deg ) the centre of clutch is normally in darkness because it is so low down on drive belt, you will need to shine a torch onto the pulley to make sure the centre part is rotating.   Look at the alternator pulley,  there is another pulley right below it with a zinc plated cover and below that is another pulley,  that is the aircon clutch, right down near the front chassis member and hardly visible. As you rightly say the clutch should turn when radiator fans are running.

I would think that even when the gas leaks out the lubricant stays in the system.

https://mdhmotors.com/ac-compressor-clutch-diagnosis-repair/ac-compressor-clutch-exploded-view/

left click on the picture to get a magnified view
« Last Edit: June 10, 2021, 03:15:03 PM by culzean »
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bill888

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Re: Aircon failure.
« Reply #7 on: June 10, 2021, 06:25:07 PM »
fwiw, have you looked through the lower front bumper grill to see if there is any signs of new stone impacts on the condenser?

2007(57) Jazz 1.4SE CVT-7 (GE3 - made in China)

VicW

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Re: Aircon failure.
« Reply #8 on: June 10, 2021, 06:58:35 PM »
Yes I have Bill but nothing obvious. There is dye in the system to detect leaks but I am not sure if you need a special light for it to show up, ultra violet for instance. Condenser leaks caused by stone impacts are about the commonest causes of leaks.

Vic.

VicW

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Re: Aircon failure.
« Reply #9 on: June 14, 2021, 03:30:35 PM »
Car was in for investigation this morning. Not surprisingly they found that the gas was low, only about 100gms remaining, which accounts for the AC not working
They recharged the system and the AC works fine, eliminating any compressor or electrical problems. They were unable to detect any leaks and an ultra violet light source is used to highlight the dye in the gas. My next course of action is to suck it and see, if it leaks again then more work will be required including better access to the condenser as the most likely cause. I was not charged for the work done this morning.

Vic.

culzean

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Re: Aircon failure.
« Reply #10 on: June 14, 2021, 05:07:07 PM »
Car was in for investigation this morning. Not surprisingly they found that the gas was low, only about 100gms remaining, which accounts for the AC not working
They recharged the system and the AC works fine, eliminating any compressor or electrical problems. They were unable to detect any leaks and an ultra violet light source is used to highlight the dye in the gas. My next course of action is to suck it and see, if it leaks again then more work will be required including better access to the condenser as the most likely cause. I was not charged for the work done this morning.

Vic.

https://www.halfords.com/motoring/engine-oils-and-fluids/air-con/superseal-air-conditioning-leak-sealant-mrl-3-134448.html

I have used this on cars before, but they do advise blowing through the LP fill valve with R134A gas after you have blown leak sealer into the system,  just in case the sealer 'seals' the fill valve  :o   I was OK because I usually keep a cylinder of STP gas in garage and just blow a bit in every year.    Trouble is with rubber hoses they get porous after a few years,  and when aircon is not being used the internal pressure equalises throughout the system,  so the LP side that is normally at 25 to 30 PSI when running gets up to over 200PSI when it is not running ( pressure depends on ambient temperature ).

The sealer reacts with moisture in the atmosphere if it gets pushed through porosity or small holes to 'set' it.

I couldn't believe my eyes when Halfrauds was the cheapest - but their prices do seem more reasonable these days.

The automatic gas change machine should detect any significant leak in the system while it is going through its sequence - but I wouldn't expect it to detect really small leaks.
« Last Edit: June 14, 2021, 05:38:57 PM by culzean »
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MartinJG

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Re: Aircon failure.
« Reply #11 on: June 15, 2021, 12:46:46 AM »
Car was in for investigation this morning. Not surprisingly they found that the gas was low, only about 100gms remaining, which accounts for the AC not working
They recharged the system and the AC works fine, eliminating any compressor or electrical problems. They were unable to detect any leaks and an ultra violet light source is used to highlight the dye in the gas. My next course of action is to suck it and see, if it leaks again then more work will be required including better access to the condenser as the most likely cause. I was not charged for the work done this morning.

Vic.

Just be a bit careful there, Vic  :o

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