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Old 18th July 2022, 23:55   #11
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Originally Posted by TomTheTyke View Post
Update as of 11.15pm. Popped out to the car just before bed, gave it a try now everything had ‘cooled down.’

We had cold air again almost straight away.

Not sure if this is possible but there is no shade in the car park at work so car was stood all day in direct sun, then engine running adding to that. Could it be a symptom of tired compressor / condenser just not being able work efficiently enough in those temperatures?

Again my lack of AC knowledge is showing, no such issues in the TF!

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Edit to reply Arctic: thanks for the info, I will check the demist but when I just turned the AC on auto earlier, the fan came on, but would that be testing the right speed? Condenser looks OK in terms of major damage but presumably bumper off to have a proper inspection?
Hi Tom.
Did you start the car making sure all air con was off, then press the demist button, look through the front grill and see the fan running continually ? if not then all you heard was the internal fan.

Please do the above and report back, all fans and condensers are going to be tested over the next few days and weeks with this heat.
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Old 19th July 2022, 07:56   #12
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Sounds like a cooling fan issue follow Arctics excellent guides on the fan which will help
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Old 19th July 2022, 08:43   #13
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My condenser & compressor were both replaced with new items ... However though it does blow cold l do have a feeling that it could be better.
I think Gary has hit the nail on the head here. I have thought the same thing about both my cars' air conditioning but in the current high temperatures (mid to upper thirties) I'd say that we are expecting too much.

When a car has been standing in intense direct sun the interior effectively becomes an unventilated greenhouse. No system is going to be capable of quickly reducing the temperature by 15 or even 20 degrees which is what we all expect. Now I can hear dissenting voices!

At the weekend I travelled in a friend's company car; a brand new BMW 330 petrol hybrid and ambient temperature was 27 to 30˚c. It certainly wasn't ice cold inside. The system was running continuously at a high blower speed with manual switching between fresh and recirculated air intake to maximise the cooling effect. The journey was about an hour on a motorway and single carriageway A roads. It was tolerable inside the car but I wouldn't say I was particularly comfortable and the system never attained the target temperature of 20˚. This is a brand new vehicle, not a 20 years old MG Rover.

Now on to Tom's first post.
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Originally Posted by TomTheTyke View Post
Think compressor is running ... a 'clicking' noise every 3 or 4 seconds from the compressor area.
Radiator fan did come on once air con was engaged as well.
The way to check your compressor Tom is to watch the pulley whilst an assistant switches between 'Econ' and 'Auto' modes. When the air conditioning is switched on ('Auto' mode) the centre of the pulley should begin rotating and remain so. If it's cycling every 3 or 4 seconds between engaged and disengaged then that means that your refrigerant pressure is either too low or too high. The reason for this would need investigating but as you've said that the radiator fan is running continuously it's very unlikely to be that.

Google an automotive mobile air con. specialist near you. He'll have the equipment to check your refrigerant charge and a pressure gauge set to diagnose the problem accurately.

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Old 9th August 2022, 13:17   #14
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Afternoon all,

Sorry for the delayed reply, work then a fortnight's holiday got in the way.

All suggestions much appreciated. I have been doing some tinkering today so have finally tried the points from Arctic and Simon.

i) The fan is working when the demist is switched on.

ii) The compressor also seems to be working; the centre is still in Econ mode then spinning consistently when the aircon is on.

We do still also have cold air, even now as I've just checked and it's above 25C; so it really was just the two days when the temps were very high.

AFAIU that still leads to the same 2 possibilities - either it has lost some gas or there is a weakness with the compressor or condenser being past best. I think a specialist would be required to diagnose? Whether or not I get that far this year, with the system working relatively well, remains to be seen.
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Old 11th August 2022, 06:45   #15
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Thanks for the update Tom. When you return to a very hot car interior, the "lazy venting" feature (activated by T4) is useful but if you haven't got that I recommend the following:
  1. Lower the rear windows by a few inches to provide a flow of air through the interior.
  2. Select 'Auto' mode and set both temperature controls to 'LO'.
  3. Cancel the automatic recirculation setting.
  4. After a couple of minutes when you feel that the fanned air is becoming cooler, close the rear windows and manually select recirculation.
  5. As you become more comfortable, cancel recirculation and to reduce blower noise set the temperature controls slightly higher, for example 17˚.

I hope that's useful.

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Old 11th August 2022, 08:44   #16
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Thanks very much.

Funnily enough yesterday when the dash display topped 30C, it did seem to struggle again, will give this a try.
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Old 13th August 2022, 10:57   #17
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Not sure, but I am not sure people run the aircon properly. If you are only getting a low blowing from the aircon into the cabin, try this:- the plus and minus sign on the aircon console, press the + sign, and you will find that you get a good blast of air through the vents. As the temperature goes down, the fan inside will slow down to a steady speed.Also press the ‘little man’ to alter where the air is blown out. My aircon is set at 20deg, and stays throughout the year as such.
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Old 14th August 2022, 18:44   #18
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Originally Posted by bl52krz View Post
Not sure, but I am not sure people run the aircon properly. If you are only getting a low blowing from the aircon into the cabin, try this:- the plus and minus sign on the aircon console, press the + sign, and you will find that you get a good blast of air through the vents. As the temperature goes down, the fan inside will slow down to a steady speed.Also press the ‘little man’ to alter where the air is blown out. My aircon is set at 20deg, and stays throughout the year as such.

Thanks, but the issue I had wasn't a low force from the aircon, rather that it was forcefully blowing hot air, because the system was trying but failing to get down to the target temp of about 20C. Normally I'd say this would mean no gas, but as the thread described it seems to only happen when the temperature the aircon is being asked to cool is very high, say about 30C + external, meaning considerably higher in the car.

In theory, there needn't be any need to adjust those settings as 'Auto' should do the trick.

As it happens I took the car on a round trip of about 150 miles yesterday in very hot conditions. Opening the rear windows to 'pull' some air through as opposed to relying on auto recirculation definitely helped (thanks Simon).

On the motorway the car was fine even with windows up, but obviously lots of air flow to the condesner and the cabin was already cooler by this point. Once we stopped in traffic at the other end of our journey we struggled again and increasingly just blew hot, but the external temp was by then reading 31.5C.

On the way home in the evening, with temperatures a bit lower externally, the aircon was 100% icy cool.

All this leads me to think it could just be extreme temps and tired, 21y.o. equipment, rather than a gas leak. I also know the only real way to tell would be to see a specialist, but as it's pretty much working in all but the most extreme conditions - slow inner city traffic with over 30C - I think that might be one that we let ride through the winter and see how we go.

Thanks again for the all the help.
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Old 15th August 2022, 07:17   #19
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On the motorway the car was fine even with windows up, but obviously lots of air flow to the condesner and the cabin was already cooler by this point. Once we stopped in traffic at the other end of our journey we struggled again and increasingly just blew hot, but the external temp was by then reading 31.5C.
Thanks for this helpful description Tom. Your system should not have been blowing "hot" air, even with 31.5˚C outside and since this occurs when there is no ram effect upon the condenser I'd suggest checking the following:
  • I see that your car is a 2001 V6. Does it have a 3 speed fan? I know that it's passed the demist test for slow speed, but it's possible that the higher medium speed (triggered by high air conditioning demand) isn't working if the relevant brush (grey wire) is worn.
  • Your condenser may be past its best. Inspect the lower rows of fins for damage which are the most susceptible to rainwater and debris. This would reduce the surface area and therefore the efficiency.

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Old 15th August 2022, 09:28   #20
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Thanks for this helpful description Tom. Your system should not have been blowing "hot" air, even with 31.5˚C outside and since this occurs when there is no ram effect upon the condenser I'd suggest checking the following:
  • I see that your car is a 2001 V6. Does it have a 3 speed fan? I know that it's passed the demist test for slow speed, but it's possible that the higher medium speed (triggered by high air conditioning demand) isn't working if the relevant brush (grey wire) is worn.
  • Your condenser may be past its best. Inspect the lower rows of fins for damage which are the most susceptible to rainwater and debris. This would reduce the surface area and therefore the efficiency.

Simon
Thanks again for the help. Interesting to learn how the system works. I suppose when I say 'hot' I mean 'ambient' air, it's just that it was hot yesterday!

The car is relatively low miles, 47k ish and 7k of those are me in the last year, so it may well be on the original 3 speed fan if that's what was fitted. Is there a way to know which I have?

This thread seems to be the best way to test operation? https://www.the75andztclub.co.uk/for...hlight=trinary

I've done plenty of mechanical tinkering but never messed about with electrics before!
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