7 replies to this topic

[GoldPod]

Hi all,

 

Just bought a Citroen Picasso (Xsara Picasso, 2006, 1.6HDi Exclusive) Been meaning to for years, and so far very glad I finally have.

 

Just one real problem, with the aircon not working (tho supposedly very recently regassed). No cold air at all through any of the vents; No click of the compressor kicking in when it's switched on. Interior fan works effectively on all speeds, nothing untoward there. 

 

However, have noticed that when restarting with a warm engine, there's a noise like something inside the dashboard is knocking. Not all that loud, like the rubber handle of a screwdriver being knocked against the inside;, lasts for about 5-10 seconds, louder, about 4 beats per second at first, getting quieter and less rhythmic until it stops. 

 

Putting two and two together (and maybe making five?) found that various internet searches point to something called the aircon flap (or door) actuator? (Maybe also known as "Air Conditioning / Heater Flap Reduction Gear /Damper motor")

 

Could a problem with this be what's causing the prob with the aircon? I've searched these forums but so far been unable to find anything similar, tho maybe I'm missing something? Also spent several hours searching online but been unable to find this exact problem on a Picasso.

 

Anyone come across this before or got any pointers to what it actually might be? Could the two things be unrelated, and if so, what is the knocking?

 

Car runs really well otherwise, everything seems to work as it should, no warning lights or messages on dash (other than needs a service), Done 144000 miles but looks and drives like half that.

 

Thanks for any advice

[stimulator]

This maybe some help. I talk now of a C3 saloon. Aircon is provided by the compressor band an evaporator. The compressor is driven by the engine the evaporator is in the heater box. This cools the air that is passed through it. The air exits and then passed through or partially through or bypasses the heater matrix. The air is diverted etc by s flap. The flap is driven by a motor via a gear. On the C3 that gear had a habit of stripping a tooth or two which made a ratcheting noise as thevmotit tried to drive it. If you have auto Aircon then you have motor driven flaps, if manual Aircon then the flaps are mechanically linked by rods.

[GoldPod]

Thanks stimulator

 

Yes it is auto aircon, and the display shows A/C when the button is pressed, tho no click from compressor or change in engine idle.

 

Hmm - wondering if there's two faults here: 1, the compressor not kicking in, and 2, the aircon flap/motor. 

So...:

1: is there a way of manually actuating the compressor - a relay or connection somewhere that will actuate it to test it?

And

2: Anyone know how to even get at the flap actuator motor to test that?

 

Thanks again

 

[stimulator]

When the Aircon is switched on the engine cooling fan is also switched on at low speed. This ensures the condenser is cooled. If the fan doesn't run the compressor doesn't engage. Condenser is mounted behind the car rad. There are two safety switches in the system low pressure and high pressure. The low pressure is activated by lose if refrigerant in the system and prevents the compressor engaging. The other is high pressure which as it says operates if the system overpressured and cuts it out. This is a common fault from overcharging the system with refrigerant.

Edited by stimulator, 02 May 2018 - 05:58 PM.

[discv]

In my opinion, the heater flaps may or may not be working correctly. But they will not prevent the A/C compressor from kicking in.

The fact that the system was regassed is the clue. Unless whatever allowed the previous gas charge to escape has been fixed- the new charge will also leak away. You need someone who can detect the leak- and that will be A/C specialist territory. Kwik Fitup will tell you their machine senses leakage- but it will not detect a slow leak, only a sizeable loss over around 1 minute. 

 

There are 3 flap/motor assembles. They can all be got at after removing the lower centre facia- just about!

[cris1117]

Hi. I had to change the engine cooling fan on mine, not a big job just expensive and a fairly common thing on the 1.6 HDI.
Try the free stuff first, with the engine running is the engine cooling fan working when you switch the aircon on?
If not try to get on a quite road at about 30mph switch on the aircon and see if it blows cold, you will need to maintain 20/30mph for a few minutes to keep the airflow doing the work of the fan.

[cris1117]

Hi. Just found the thread that helped me repair my a/c, maybe of some use to you.



http://www.citroenpi...ing#entry175388

[GoldPod]

Thanks to all who posted suggestions trying to help, sorry it's been a while getting back to update you, had ISP problems.

 

Anyway, the car's now been fixed    , turned out the problem was a v-e-r-y s-l-o-w leak in the evaporator, which has now been replaced (free of charge!) So lotsa nice frosty air, which has been very welcome over the past few warm days.

 

As you surmised stimulator, the knocking appears to be being caused by a divertor flap, which seems to struggle a bit but gets there eventually. So as you said discv, it may or may not be working, but not the cause. Looking at the work required to get at them, I think this'll have to wait for a day when I have much more time available than lately.

 

Thanks guys