Any ideas why air con would suddenly go really cold?

I have my heating turned up (hot/cold dial to full heat and temp set to max) no problem. If i set temp to around 22 at some point it suddenly swaps to pushing out really cold air?? turn to full and heat comes back? its really irritating ....... 2007 3.0L Diesel VW Touareg SE
2003 4.4 LPG, Vogue, Silver

is the Wife in the car? that's usually what f**ks around with the settings in mine....

Could be an airlock in the system, anything other than the coolant level at max can introduce bubbles into the system that then group and can cause issues. Usually giving it a bit of welly increases the flow and disperses the airlock.

I also notice you have LPG - depending on where they have tapped into the coolant pipes you could find this is causing the problem (the water will choose the path of least resistance etc)

The other thing, if it only happens at lower revs is the Auxiliary coolant pump could have failed, quite common on BMW's around the same age and it is a BMW part... 

Bienbn wrote:

is the Wife in the car? that's usually what f**ks around with the settings in mine....

just told the wife its her fault 2007 3.0L Diesel VW Touareg SE
2003 4.4 LPG, Vogue, Silver

thank you dan, sounds complicated so as summer is on the way, cold is fine by me  2007 3.0L Diesel VW Touareg SE
2003 4.4 LPG, Vogue, Silver