Citroen C3 Air-con issue

[Riccoupe]

Hi looking for some advice/confirmation please ?

The son’s car (first run-around after passing his driving test) is a 2011 1.4 (75hp) Citroen C3 Connexion.
I’ve had great assistance on this site concerning issues with the Sat-Nav, etc., and hope that someone will be able to offer some advice re the current issue ?

The issue is that the air con is not cooling. The system has been pressure tested and re-gassed and there are no leaks.
When you press the air con button on the dash there is a slight change in engine revs as expected, but the compressor doesn’t “kick-in”.
Apparently the Re-gas guy was able to manually engage the (magnetic ?) compressor clutch by levering it, but it wouldn’t stay in place ? (I wasn’t actually there so am getting this information third-party. Apologies).

From other similar posts I’ve read here it seems that the main engine Radiator Cooling Fan should be running all the time when the air-con is selected ? Could someone please confirm if this is correct as it doesn’t currently engage (in fact I’ve never seen it running, but maybe it hasn’t needed to as the car only gets small trips ?)

I honestly can’t remember 100% when the air-con last worked. A faulty external temperature sensor was replaced, and a BSI Reset was done to try and (unsuccessfully) solve an issue with the time not appearing in the Radio Display, but I’m not sure if the air-con was working before and after those replacements/procedures.

It’s an old car that we don’t really want to throw a lot of money at, so any guidance re the air-con would be gratefully received (e.g.; should the fan run ? is it worth getting a second-hand-compressor ? maybe change a temperature sensor (?) at the top of the radiator ?)

Sorry for the long post.

Regards, Ric

[RichardW]

You'd need to get it on the computer to see what info there is on the circuit - low / high pressure, or other faults?

You could check if there is 12V getting to the compressor, and if it will engage if you supply 12V to the compressor clutch.

[xantia_v6]

I think that you are on the right track with the cooling fan, but it is still probably best to have the fault codes read to save some guesswork.

[Riccoupe]

Many thanks for the very quick replies RichardW and xantia_V6.

I have used a couple of "generic" ODBC fault code readers, but as expected nothing was reported.
Was trying to avoid buying a lexia device in case we don't end up keeping the car for long.

I'll see if the local mechanic has any time to try applying 12v to the compressor as suggested as I don't really have the facilities or tools here to do so.

Thanks again.

[ozvtr]

The issue is that the air con is not cooling. The system has been pressure tested and re-gassed and there are no leaks.
When you press the air con button on the dash there is a slight change in engine revs as expected, but the compressor doesn’t “kick-in”.
Apparently the Re-gas guy was able to manually engage the (magnetic ?) compressor clutch by levering it, but it wouldn’t stay in place ? (I wasn’t actually there so am getting this information third-party. Apologies).

All of those symptoms point to worn clutch plates on the compressor.
There is a particular gap between the 2 clutch faces when the clutch is disengaged. This is shimmed (adjusted) at the factory. Over time the clutch plates wear and this gap gets bigger, to the point where the clutch wont engage. It's a simple matter of removing the drive plate and removing shims to get the correct gap.
To check this diagnosis, remove the fender liner, start the engine and start the A/C. Tap the face of the compressor clutch with a rubber mallet (or similar). If it begins to spin, The clutch needs to be adjusted.

[ozvtr]

I have used a couple of "generic" ODBC fault code readers, but as expected nothing was reported.
Was trying to avoid buying a lexia device in case we don't end up keeping the car for long.

The point of OBDII (and EOBD) is for emissions ONLY! ANYTHING that will cause an engine to run poorly is reported by the OBD reader. It's very handy to diagnose most ENGINE faults. But it WILL NOT report anything other than something that may cause emissions faults (including EVAP and catalyst faults).
If you want to look at anything other than that, you will need a proper scan tool.

[Riccoupe]

Thanks for the replies ozvtr. Certainly sounds like a possible cause.
Yeah, I meant OBDII. I work in IT so got my letters mixed up lol.
Thanks for the explanation.

[No10Chris]

I agree with the clutch diagnosis, had exactly the same on an old Range Rover, re shimmed and it was fine

[xantia_v6]

If it is a faulty compressor clutch, then the clutch solenoid will have voltage which you could measure, and you should hear it click a few seconds after starting the engine. A diagnostic tool will show that the the compressor clutch is engaged.

[Riccoupe]

Many thanks No10Chris and xantia_v6.