HOT AIR flowing from air vent when CLIMATE CONTROL is off

[geoffp]

Didn't work. I have digital control, the recycle button does nadda unless the air-con is on.

I will get it looked at when I have my 15k service - currently a bit over 12k.

[OzBoz]

If you are going to mention it at your next service, I would suggest you had some hard figures to hand, or you are going to get the "thats normal" answer from the techs.

Get yourself a little thermometer and measure the output temps at the vent, so you have the evidence.

I believe that a small amount of rammed airflow when moving is normal, in order to avoid drowsiness and asphyxiation when driving with all windows closed, but it shouldn't be warmed.

BTW, if you are using climate control to warm the car in cold weather, (at least in my last car) the air con is still working to de-humidify the air.

Cheers

Brian

[Jester_Fu]

I had this on my last car with climate, and the solution to fix it is the same in my new R32 (MkV) - turn the AC on, let it cool, turn the AC off.

The climate control works to try and achieve a target air temp by mixing hot air and cold air from the heater core and evaporator respectively. There is a 'flap' between the two air paths that allows the air to mix. So, in effect, what you're doing by turning the AC on, letting it get cold, then turning it off is forcing the flow valve to the heater core off and the 'flap' in the mixer closed, blocking off air flow.

It seems silly, but my understanding is the heater core valve in euro cars is programed to open when you turn the car off simply so the core can not freeze and crack during very very cold temperatures - there is somewhere for the water to flow as the core cools and contracts; the radiator. What you're experiencing is a memory effect from the flap and the protection the program applies to the heater core when you turn the car off.

I never bothered trying to get it fixed on my last car. To be honest, i only ever turned the climate off when going for a spirited drive or on lovely spring days. I've been doing it more often in the R32 because of the sun roof and glorious NSW weather of late I'm not going to bother talking to the dealer about it - i know how to shut the hot air off if i want. If you guys need another body to request the mod and help get VW to change the sotware, let me know. Otherwise... i'll just turn the AC on then off

[pinzvidz]

sadly not... aircon uses up quite a bit of fuel, especially at idle.

That's not entirely true. If you're talking about older vehicles with conventional reciprocating or early scroll type A/C compressors, then yes, they'll use a bit more fuel. However, newer compressors are very efficient and will make very little if any difference to your fuel bill. To the OP... just leave your CC on, it's going to do very little A/C cycling on a cool day anyway.

[The_Hawk]

I believe that a small amount of rammed airflow when moving is normal, in order to avoid drowsiness and asphyxiation when driving with all windows closed, but it shouldn't be warmed.

If thats the case it's not entirely unexpected that the air is warmed, the vents it travels through will be close to the firewall so will get some residual heat, especially when it's slow moving. But lets face it, if it's hot enough to bother you, chances are your going to have the AC on anyway, or the fans and the windows... or something else to the point where you won't notice.

Even so it's worth asking the dealer if they know about it.

[Mischa]

That's not entirely true. If you're talking about older vehicles with conventional reciprocating or early scroll type A/C compressors, then yes, they'll use a bit more fuel. However, newer compressors are very efficient and will make very little if any difference to your fuel bill. To the OP... just leave your CC on, it's going to do very little A/C cycling on a cool day anyway.

my car uses almost double the fuel idling with aircon on than it does without it on, i can also notice the power loss

[Jester_Fu]

^Is that from the GT TDI or the Mk2 you're talking about? I'd be surprised to hear it makes a big difference in the GT TDI. The AC should have very little impact on the torque at idle with the diesel engine.

[NickZ]

Dont VW fit bigger compressors for warmer climates like ours? Perhaps this impacts air condition and performance more than it does on euro spec cars?

I notice a big difference in my car on idle - 0.8l/100 without air con versus 1.0l/100 with air con. Without air con after a normal drive it is always below 8.5l/100, whilst with air con it tends to be around 9.5l/100.

[Mischa]

^Is that from the GT TDI or the Mk2 you're talking about? I'd be surprised to hear it makes a big difference in the GT TDI. The AC should have very little impact on the torque at idle with the diesel engine.

thats my gt tdi. hovers round .6 per hour without aircon and around 1 or 1.1 with aircon. i rarely use aircon anyway so it doenst bother me. does it not make a difference on your car?

[Jester_Fu]

Doesn't seem to make any difference in the R... probably because it kills a baby whale every time i start it up

I'm surprised the GT TDI uses more juice Does it effect your average consumption much? Just curious...

[Mischa]

Doesn't seem to make any difference in the R... probably because it kills a baby whale every time i start it up

I'm surprised the GT TDI uses more juice Does it effect your average consumption much? Just curious...

lol well im not really one to talk to about average consumption... i barely ever use the aircon and ive never heard of anyone getting a higher average than i do