Smelly car (BMW)

VfM4meplse

Ultrasonic wrote: »

How about winter when it will be off most of the time?

Ironically, mine is on a lot more over winter - usually at 23 degrees!

Ultrasonic

VfM4meplse wrote: »

Ironically, mine is on a lot more over winter - usually at 23 degrees!

The AC compressor won't be though. Well not unless it's a really inefficient sytstem. It's off in my car in winter apart from first thing when I'm clearing the windscreen.

Edit: Although actually this means that my AC compressor is used far more frequently in winter than summer.

Iceweasel

If your car has Climate-Control it will be using the AC compressor to dry the air in the car in the winter when humidity is usually higher.

If you have a simpler AC system you should run it at the same time as asking for heat on the temperature control dial.

Some folks question the use of the AC 'snowflake' button and asking for heat at the same time, but it should be remembered that AC stands for Air Conditioning not Air Cooling.

chrisw

Yes, turn it on and leave it to do it's thing. That's how it was designed to operate. The compressor works a fair bit in the winter drying the air unless the outside temperature is less than around 5 degrees to prevent it freezing. Turning it off might feel like saving money but just introduces a load of further problems which can be difficult or costly to rectify.

Ultrasonic

Iceweasel wrote: »

If your car has Climate-Control it will be using the AC compressor to dry the air in the car in the winter when humidity is usually higher.

Not in a VAG car with the ECON button pressed. I don't know more widely.

(It's not especially relevant, but I suspect absolute humidity is higher in summer than winter.)

Iceweasel

Ultrasonic wrote: »

Not in a VAG car with the ECON button pressed. I don't know more widely.

That's very true - with the 'econ' button pressed you'll have only hot air to clear the screen.

With the button un-pressed you should get hot dry air IIRC.

Ultrasonic

Iceweasel wrote: »

That's very true - with the 'econ' button pressed you'll have only hot air to clear the screen.

In my 2005 car, pressing the windscreen demist button automatically turns the compressor on, and this is what I use to initially clear the windscreen. I'll try to avoid heating if I can until the engine has warmed up (to help the engine warm up quicker) and then switch on heating in ECON mode.

chrisw wrote: »

Turning it off might feel like saving money but just introduces a load of further problems which can be difficult or costly to rectify.

Could you be more specific? Does it really need to be on all of the time or is there some periodic use that would keep everything healthy without the fuel economy cost? (I don't wish to derail the OP's thread but hopefully this is still of some interest.)

neilmcl

oldhand wrote: »

Interesting thread,a neighbour bought a new bmw 5 series a few months back and often he passes me in the lane when im out for a walk.I mentioned to him each time he passes me theres a smell for all the world like demestos bleach from his exhaust,I assume its from the catalyst as its only in the morning when the cars first started.He himself smells it when he has the window down at the end of the road but to him it smells like "pee".

Possibly got the Blueperformance option.

neilmcl

VfM4meplse wrote: »

Whoops! Corrected the link now

The care is a 3 series diesel, just over 12 months old.

Exactly which model?

neilmcl

VfM4meplse wrote: »

13 months and I've never refreshed the aircon. I don't use it that much and there are less than 9k miles on the clock.

I'd leave it on all the time. Makes little difference to the economy on the newer BMWs with start/stop technology and as previously stated will keep the system in good nick. Using the a/c infrequently doesn't do it any favours and allows bacteria to build up.