No Heat

[LightlyToasted]

Originally Posted by Nanniepoo

I would think '07 and '08 would be fairly similar, but I didn't have to dig through the wheel arch to get to the aux pump. I had ok access in the engine compartment. I can't tell you when specifically it turns on, but if you hold accel pedal down with ignition on (engine off), it'll kick on. Supposed to help you bleed coolant. I could hear it run, but a hand on it will certainly be obvious if it's on or off.

I don't think that's the case for the N62 (4.8i) which has a mechanical water pump - that's the procedure for the N52 (3.0i) with electric water pump.

[LightlyToasted]

Originally Posted by RockDriver

I think I have a similar if not exactly the same problem. 2009 N62 V8 here. But my biggest suspicion is the electric flaps that regulate the air flow. Because my vents barely blow any air even when the fan is set to max, but after driving for some 15 minutes the car does warm up. So it can't be the valve, can it?

Note that the vents will barely blow any air if the system is in auto mode where I suspect that the system is attempting to avoid blowing cold air in your face when it senses not enough heat in the heater core. To check your air flaps you would switch to the manual modes and turn up the fan, which seems to be what you've done.


If the heater valve and aux pump and heater core are working then you'll get warm air in the cabin from whatever vents are working.

[RockDriver]

Originally Posted by LightlyToasted

Note that the vents will barely blow any air if the system is in auto mode where I suspect that the system is attempting to avoid blowing cold air in your face when it senses not enough heat in the heater core. To check your air flaps you would switch to the manual modes and turn up the fan, which seems to be what you've done.


If the heater valve and aux pump and heater core are working then you'll get warm air in the cabin from whatever vents are working.

I've tried everything - auto mode, manual mode, AC on, AC off, no dice. Also, when AC is on, it only blows cold air, even though the temp is set to maximum. Interesting, so according to what you said, I guess in the end it could still be the valve.

[Nanniepoo]

Originally Posted by LightlyToasted

I don't think that's the case for the N62 (4.8i) which has a mechanical water pump - that's the procedure for the N54 (3.0i) with electric water pump.

I have the N62 and am pretty positive I did that as part of my diagnosis. I can try today because I suppose there's not much value in you trying because if it doesn't work is that the pump or the dude on the forum?

[AllyG13]

Having recently retrofitted a webasto evo5 engine heater to my e70 I would say you have an issue with the twin port heater valve for dual climate control. Sounds like the normally open un-powered valve is getting power when it shouldnt or its stuck closed, Id check the wiring to the valve with a multi meter first then replace the valve if its ok.

[AllyG13]

You could also try swapping around the pipes at the twin port valve to see if the other half of the heater matrix warms up.

[LightlyToasted]

Originally Posted by Nanniepoo

I have the N62 and am pretty positive I did that as part of my diagnosis. I can try today because I suppose there's not much value in you trying because if it doesn't work is that the pump or the dude on the forum?

Please let me know how that goes. If the N62 has a coolant bleed mode that would be really useful, but I wonder how well such a small and isolated pump would do for the whole cooling system. It worked really well on my X3 with the N52 with electric water pump.



IIRC the "rest" mode, where you hit the fan up button after turning off the vehicle, is supposed to circulate coolant through the heater core via the aux water pump. I tried that, and couldn't detect any noise or vibration from the aux water pump, but it's hard to get to from the top. I have some time this weekend so I'll take the wheel well liner out to get at it.


I'm also going to check my port settings for ISTA to see if I can get it to talk to all of the modules.

[LightlyToasted]

Originally Posted by cjshaw14

Had similar issue last year with no heat on 09 E70, replacing the valve did the trick, sorry that didn't work. But saw your ISTA comment with no comm to modules, ran in circles until I found what it was, be sure latency is set to 1. Open “Device Manager”, then USB Serial Port properties, go to “Port Settings” tab and click
“Advanced...”. Change latency timer to “1”

@cjshaw14 - thanks! This worked, and now ISTA can talk to all of the modules. The only code sticking around is E723 in IHKA - No message - condensator sensor. I don't think this is my problem.

[Nanniepoo]

Sorry, our E70 was misfiring on the way home so I got a bit distracted. However I can confirm the pump was running with ignition on, with me doing nothing.

Post #2 seems to match that operation: https://xoutpost.com/bmw-sav-forums/...ump-bleed.html. When calling for heat, even without the engine running, the valves open and pump runs.

[LightlyToasted]

Originally Posted by Nanniepoo

Post #2 seems to match that operation: https://xoutpost.com/bmw-sav-forums/...ump-bleed.html. When calling for heat, even without the engine running, the valves open and pump runs.

Good find! I'm pretty sure my aux water pump is not running when calling for heat, so I suspect the pump or circuit is the problem. I may be able to test it out soon and will report back.