[coolesnce]

I know our I drives have the active ventilation feature, but do you know if we have the REST button/ feature to blow in the car residual engine heat whrn the car is parked like my 2005 X5 did?

[Lotus7]

The X3 does not have a "Rest" function or dedicated button for that function. However, the X3 does have a"Parked-car ventilation function" that is timer controlled. It can be set via iDrive for the current time and will run the blower, with vents, open for 30 minutes to exhaust warm air from the car. Does the opposite of what you're looking for.

Only the start time is programmable, it then runs for a full 30-minute cycle. A second, 30-min. cycle can also be programmed within a 24-hour period. Caution: Excessive use of this function will run your battery down!

Glad to know that the X5 survived to 3005. That's quite a production run!

[coolesnce]

Originally Posted by Lotus7

The X3 does not have a "Rest" function or dedicated button for that function. However, the X3 does have a"Parked-car ventilation function" that is timer controlled. It can be set via iDrive for the current time and will run the blower, with vents, open for 30 minutes to exhaust warm air from the car. Does the opposite of what you're looking for.

Only the start time is programmable, it then runs for a full 30-minute cycle. A second, 30-min. cycle can also be programmed within a 24-hour period. Caution: Excessive use of this function will run your battery down!

Glad to know that the X5 survived to 3005. That's quite a production run!

Thanks for the info Lotus, Yeah I have used the Parked car ventilation to keep the X3 cooler on hot days, but now that it is getting cold and ill be going to snow conditions soon i was wondering how to get warm air blowing into the engine while im parked like my x5 did. Any ideas?? O h yeah typo on the 3005, if only BMWs lasted that long without costing $$$$ to maintain..lol

[xDrive35i]

Originally Posted by coolesnce

Thanks for the info Lotus, Yeah I have used the Parked car ventilation to keep the X3 cooler on hot days, but now that it is getting cold and ill be going to snow conditions soon i was wondering how to get warm air blowing into the engine while im parked like my x5 did. Any ideas?? O h yeah typo on the 3005, if only BMWs lasted that long without costing $$$$ to maintain..lol

Even with the compressor off, the blue/red knob will filter out cold or hot air depending on where the marker rests. Try pushing it all the way to the red square when turning parked car ventilation on.

[paul386]

I find turning this feature on / off to be too annoying (even after programming the menu position onto my hotkeys). It needs a dedicated button on the console!

[coolesnce]

Originally Posted by juddholland

Even with the compressor off, the blue/red knob will filter out cold or hot air depending on where the marker rests. Try pushing it all the way to the red square when turning parked car ventilation on.

l'll try that and see if it helps. Ill do it on a cold cold day so ill know if its pumping in cold outside air or warm residual engine heat.

[Nahoa]

If you turn of the car and keep the electronics on the fan keeps operating, don't they? Will that move heat off the warm system? Maybe this is the Rest function without a dedicated button? Not cold enough here at the moment to give it a try.

[Lotus7]

Originally Posted by Nahoa

If you turn of the car and keep the electronics on the fan keeps operating, don't they? Will that move heat off the warm system? Maybe this is the Rest function without a dedicated button? Not cold enough here at the moment to give it a try.

The fan keeps running and blowing air through the heater core, but the heated water in the engine block is no longer circulating. Within a few minutes, the residual heat from the 1/2 liter of warm coolant in the heater core is exhausted, and the fan just blows cold air. The engine block and the 8 liters of coolant in the block and cylinder head still is warm but that energy can't get to the heater core to be transferred to the air being circulated into the passenger compartment.

On some X3 (F25) models, the possibility actually exists to implement a "residual engine heat extraction system". The 28i (N52) engine and the 35i (N55) engine both use an electrically driven water circulation pump. The pump is controlled by a coolant temperature sensor and the engine "BSM" (Basic Control Module). The pump only runs when the engine gets hot and the pump speed is modulated to match engine and turbocharger load (F55 only). The programming is optimized to save energy (fuel).

It's theoretically possible (actually would only take some code to be added) to run the engine circulating pump at the same time as the heater fan. That would circulate the engine's stored energy (heat) to the heater core and allow it to be transferred to the passenger compartment until the engine block heat was exhausted.

The only issue with the system is the additional battery energy that would be used. Currently, if you run the blower on battery power with the engine off the current will quickly deplete the battery. That's why there's a 30 minute limit on the timed interior ventilation system. Running the (high-current) water pump in addition to the fan would deplete the battery even faster. Maybe the limit would have to be reduced to 10 or 15 minutes, but those would be toasty warm minutes.

Footnote for 20i, 30d, and 35d engine owners: Unfortunately, the 20i engine uses a mechanical, shaft driven coolant pump, and the 20d, 30d, and 35d all use belt driven coolant pumps. No way to run those when the engine is not turning over. Sorry.

[paul386]

Originally Posted by Lotus7

The fan keeps running and blowing air through the heater core, but the heated water in the engine block is no longer circulating. Within a few minutes, the residual heat from the 1/2 liter of warm coolant in the heater core is exhausted, and the fan just blows cold air. The engine block and the 8 liters of coolant in the block and cylinder head still is warm but that energy can't get to the heater core to be transferred to the air being circulated into the passenger compartment.

On some X3 (F25) models, the possibility actually exists to implement a "residual engine heat extraction system". The 28i (N52) engine and the 35i (N55) engine both use an electrically driven water circulation pump. The pump is controlled by a coolant temperature sensor and the engine "BSM" (Basic Control Module). The pump only runs when the engine gets hot and the pump speed is modulated to match engine and turbocharger load (F55 only). The programming is optimized to save energy (fuel).

It's theoretically possible (actually would only take some code to be added) to run the engine circulating pump at the same time as the heater fan. That would circulate the engine's stored energy (heat) to the heater core and allow it to be transferred to the passenger compartment until the engine block heat was exhausted.

The only issue with the system is the additional battery energy that would be used. Currently, if you run the blower on battery power with the engine off the current will quickly deplete the battery. That's why there's a 30 minute limit on the timed interior ventilation system. Running the (high-current) water pump in addition to the fan would deplete the battery even faster. Maybe the limit would have to be reduced to 10 or 15 minutes, but those would be toasty warm minutes.

Footnote for 20i, 30d, and 35d engine owners: Unfortunately, the 20i engine uses a mechanical, shaft driven coolant pump, and the 20d, 30d, and 35d all use belt driven coolant pumps. No way to run those when the engine is not turning over. Sorry.

Since the pump is already PWM capable (you said it modulates speed during operation to match engine load) the pump could be put on a very low setting to save energy. Seems like this feature is a must as it existed on previous BMW's and was quite useful in the winter. Shame!

I wish car companies started updating software / adding features with regularity of computer manufacturers or cell phone manufacturers. These cars are becoming techy enough that this seems to be mandatory going forward (and a required change in thinking for automotive companies).

[Lotus7]

Originally Posted by paul386

Since the pump is already PWM capable (you said it modulates speed during operation to match engine load) the pump could be put on a very low setting to save energy. Seems like this feature is a must as it existed on previous BMW's and was quite useful in the winter. Shame!

I wish car companies started updating software / adding features with regularity of computer manufacturers or cell phone manufacturers. These cars are becoming techy enough that this seems to be mandatory going forward (and a required change in thinking for automotive companies).

Good point. Certainly running the pump at a low speed would be more than enough. or alternately, it could be cycled every few minutes for a few seconds to move some warm coolant into the heater core.

I know the car companies are extremely sensitive about letting anyone know the details of their vehicle management systems, and certainly are not going to publish any source code, but one would think that they might license some kind of "approved" developer access to parts of their system to install features such as this, as aftermarket options.

Then, of course, there are companies like ProChip who have successfully "hacked" the BMW entertainment systems to enable functions that BMW never thought of.

I suspect that the safety related system coding, including engine ancillary management is probably encrypted and not easy to get into by anyone except the factory software team.