I discovered this....

[mcbutler]

If you have been driving your Z4 and pulled up waiting for the kid to leave school/wife to leave work you obviously turn off your engine. In this weather the car soon gets cold doesn't it....
Well BMW ingenuity to the rescue, with the engine warm, ignition off just press the + button on your fan control and the heating will continue without the car running, the centre LED on the fan speed is displayed during this function. To cancel it press the fan -, used it this evening, brilliant.........

 

[buzyg]

Finally a reason to get an E89. :wink:

 

[Tcochrane92]

Until the engine gives up all its heat and stops heating the HVAC system
PTC / auxiliary heater would get around that problem though! but don't think the e89's have that...

 

[SteveSmith]

Finally a reason to get an E89. :wink:

 

[Mr Tidy]

Great idea - but I won't need to get an E89 as I've got no kids and the wife lives at another address now!

 

[Maniac]

Yes it’s called the residual heat function. Handy when waiting around. Most cars have it now.

 

[Vonlipvig]

You sir, need a beer! This will make waiting at the train station much more comfortable

 

[mcbutler]

You sir, need a beer! This will make waiting at the train station much more comfortable

I like your style Mr Vonlipvig........

 

[ph001]

Errrmmm...don't all cars do that if you just leave the ignition in the accessory position??

 

[Maniac]

Errrmmm...don't all cars do that if you just leave the ignition in the accessory position??

Typically the residual heat implementation runs the water pump in an open loop, something that doesn't happen normally until the engine is running. Therefore making the best use of heat left in the engine to keep you warm.

 

[ph001]

Got you. The N52 does in fact run the electric water pump for a while after the engine is switched off to equalise the temperature in the head. Whether it runs through the heater matrix or not though is another matter.

 

[Nanu]

Great idea - but I won't need to get an E89 as I've got no kids and the wife lives at another address now!

Some people have all the luck. Once you get an e89 you've got it made

 

[mcbutler]

Errrmmm...don't all cars do that if you just leave the ignition in the accessory position??

Nope, that just runs the heater blower which will blow cold in a few moments. The E89 runs the electric water pump as well circulating hot water from the block to the heater.