C4 grand AC

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Althesandie
Donor 2024
Posts: 17
Joined: 15 Nov 2023, 11:34
x 4

C4 grand AC

Post by Althesandie »

Hi. I have had this Picasso exclusive for years now and since getting it the AC has been a problem Have had it put on the machines at three different garages over the years and despite telling them there is definitely a leak after two to three weeks it does't cool again. Last garage said the vacuum was Ok and no leaks. Just wondering if anybody knows a proper AC specialist in the Newcastle upon Tyne area where I can get this sorted out once and for all. Any help appreciated.
RichardW
Forum Treasurer
Posts: 11083
Joined: 07 Aug 2002, 17:12
x 1054

Re: C4 grand AC

Post by RichardW »

Quite likely it needs new valves, these obviously don't leak when the machine is connected!
Richard W
User avatar
xantia_v6
Forum Admin Team
Posts: 9236
Joined: 09 Nov 2005, 23:03
x 877

Re: C4 grand AC

Post by xantia_v6 »

Also bear in mind that a vacuum test is applying 1 bar of pressure, but in normal operation, parts of the system run at 15 to 25 bar, so a vacuum test can miss small leaks.
Althesandie
Donor 2024
Posts: 17
Joined: 15 Nov 2023, 11:34
x 4

Re: C4 grand AC

Post by Althesandie »

The schraeder valves was my exact thought. Last visit they rang me and said that the vacuum was ok and did I want it gassing up. I said no and the valves were the only thing that made sense to me. He said I will let the mechanic know. Came back and said "Uh, he's already gassed it up but I won't charge you for the gas" Three weeks later hot again.
I never knew that the system ran as high as 15 to 25 bar. I suppose the only way to find it then would be with one of those "Sniffers" or with the dye detector. Wouldn't mind but they also said that the system had some gas left in so it all makes sense.
Just need to find someone who can find it. All the AC specialists just seem to be normal garages with the machine.
Thanks for the replies. It is appreciated.
User avatar
xantia_v6
Forum Admin Team
Posts: 9236
Joined: 09 Nov 2005, 23:03
x 877

Re: C4 grand AC

Post by xantia_v6 »

Try to find someone with a sniffer. Dye can work well, but only if the leak is in a visible location.

If a Schrader valve is leaking, there should be a pressure build up under the dust cap and you will hear a little gas escape if you loosen the gas cap. You can also put a detergent film across the valve opening and see if it forms a bubble.