V70 - Air Con trips off in hot weather
 

Hi,

The air con in my 2005 V70 D5 does not like it when the outside air temperature (OAT) rises above 22 degrees celsius i.e. at the point air con becomes useful.

The system has been re-gassed and will run o.k. when the OAT is below 22 degrees.

However, on warmer days it runs for about five minutes and then trips off. If it is then switched off for ten minutes it will run cold for a further five minutes once it is switched back on.

Please note that these times are all approximate but long motorway trips are now a cycle of cool-hot-hot-cool-hot-hot-cool.... and so on.

Do the symptoms ring any bells ? Where should I start my fault finding ? Should I only drive at night in the summer months?

best wishes
Skids

you say the system has been filled, did they put the correct quantity of gas in? low or high quantities will not work properly..
It is a legal requirement to carry out a leak test too, was this done correctly?

Too much gas can cause a trip-out as it gets over-pressure.

Good questions that unfortunately I am unable to answer. The work was completed by a reputable local garage.

I will try and find a garage that can check the pressure.

pressure varies widely due to ambient temperature, it bears no relation to the volume of gas in the system.


He will have to drain it out and put back the 750grams or what ever the figure is for your car . It should say on a sticker under the bonnet.

I would also check your radiator cooling fan is working , had exactly the same symptoms on a rover 75 I owned , also worth checking that your air intakes/radiator for litter and leaves as these can reduce air flow dramatically.

My 2003 S80 had a similar problem cutting out after about 10 minutes. Turned out to be the compressor clutch and specifically the need to remove a couple of the shims. Basically it is the clutch disengaging. Hope that helps.

Thanks for the additional advice.

I believe that that main radiator fan is running o.k. otherwise I would expect the coolant temperature to be higher than expected especially on warm days.

The compressor clutch is of an age where problems are probably to be expected. I will investigate it.

Does the compressor run much in the same way one on a fridge runs i.e. runs until the system reaches a certain temperature then de-clutches until commanded to re-clutch as the temperature has risen?

Also I guess it is an electro-mechanical device?

best wishes
Skids

did you check the fan? it should run at a lower speed when ever the AC is on and working...

yes the compressor runs as you said...

I have not had time to check the radiator fan yet but will try tomorrow. I have looked at the compressor clutch gap and it looks to be nearer 3mm than 5mm.

When started from cold with an OAT of 19C, the air con on fully cold and the engine at tick over the air con clutch keeps cycling in and out; approximately running for nine seconds followed by off for five seconds and so on. I have no idea if this is normal and to be expected.

I am waiting for a hotter day before conducting more tests.

S