Ac noise in cold temperature

drewdogg77 · 12-06-2019, 11:16 AM

My 650gc makes a motorized like noise whenever the temperature outside is cold through out the AC vents,, its not a watery sound its like a motor is trying to turn but stuck,, whenever the temp outside is about 73 degrees and below... Took it to the dealer and they drained out all the coolant and replaced it, they said its air in the cooling system but the noise is still there... any ideas what this could be????????
I have another appointment on tuesday 12/9/19 one of the techs said it could be the motor for the flap making the noise,, thing is they have to pull my whole dashboard out tho....

Opie55 · 12-06-2019, 01:17 PM

Too hard to say w/o being able to hear the noise. Not sure what "motorized" means, especially since you described a frozen motor as "watery."

ezmaass · 12-06-2019, 08:08 PM

I'd put my money on the motor for the flaps. If you notice, every so number of times you turn off the car, these motors seem to go through a self diagnostics test, and they'll actuate for some period of time when the car is shut down. That's the only "mechanical" or "motor"-like sound I've ever heard come from the HVAC vents... not sure what else would even be located there to make such a sound.

Only other motor related to HVAC I could think of would be blower resistor motors - having had those go on a previous BMW, it didn't make any sound, though. The result of the failure was simply spinning up/down of the fan speed randomly.

I'm going with flaps.

drewdogg77 · 12-06-2019, 10:32 PM

when the car is off i dont hear anything, its only when ac is on and the temperature outside is around 73 degrees and below, the bmw tech said only thing it could be is the flap motors but he doesnt look to sure lol,,, but they would have to pull my dash out to replace the flap motors,,, hmmm a little sceptical about that tho,,,,

SanDiego640 · 12-07-2019, 09:00 AM

Quote:

Originally Posted by drewdogg77

My 650gc makes a motorized like noise whenever the temperature outside is cold through out the AC vents,, its not a watery sound its like a motor is trying to turn but stuck,, whenever the temp outside is about 73 degrees and below... Took it to the dealer and they drained out all the coolant and replaced it, they said its air in the cooling system but the noise is still there... any ideas what this could be????????
I have another appointment on tuesday 12/9/19 one of the techs said it could be the motor for the flap making the noise,, thing is they have to pull my whole dashboard out tho....

On my E90 the blower motor exhibited similar noises when it reached the point of failure. I agree with the previous reply, I'm going with motor for the flaps or the blower motor.

thebmw · 12-07-2019, 09:59 AM

One of my 650s has a similar problem. When the heater is turned on (anything over 60 degrees on the temperature dial), it sounds like something is bubbling or an amplified water droplet sound. There is a rhythmic clunking as well that can even be felt in the steering wheel. I have cleared the cooling fluid lines and air bubbles. Although, someone suggested that there may still be a bubble stuck in one of the heating core valves. Others have suggested that a bearing in the heating core is bad. Not sure which one. Not worth the 10+ hours getting to the heating core to find out. I just turn on the heat to full, heat up the cabin, then turn it off.

12-06-2019, 11:16 AM	#1
drewdogg77 Enlisted Member 2 Rep 37 Posts Drives: 2015 650i GC Join Date: Mar 2014 Location: tamarac florida iTrader: (0) Garage List 2011 BMW 550I [0.00]	Ac noise in cold temperature My 650gc makes a motorized like noise whenever the temperature outside is cold through out the AC vents,, its not a watery sound its like a motor is trying to turn but stuck,, whenever the temp outside is about 73 degrees and below... Took it to the dealer and they drained out all the coolant and replaced it, they said its air in the cooling system but the noise is still there... any ideas what this could be???????? I have another appointment on tuesday 12/9/19 one of the techs said it could be the motor for the flap making the noise,, thing is they have to pull my whole dashboard out tho....
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12-06-2019, 01:17 PM	#2
Opie55 Colonel 1195 Rep 2,906 Posts Drives: '15 650i Convertible Join Date: Apr 2018 Location: US iTrader: (0)	Too hard to say w/o being able to hear the noise. Not sure what "motorized" means, especially since you described a frozen motor as "watery." Last edited by Opie55; 12-06-2019 at 08:35 PM..
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12-06-2019, 08:08 PM	#3
ezmaass Lieutenant Colonel 370 Rep 1,698 Posts Drives: '17 650xi GC / '15 Audi R8 V10 Join Date: Oct 2008 Location: CT iTrader: (0)	I'd put my money on the motor for the flaps. If you notice, every so number of times you turn off the car, these motors seem to go through a self diagnostics test, and they'll actuate for some period of time when the car is shut down. That's the only "mechanical" or "motor"-like sound I've ever heard come from the HVAC vents... not sure what else would even be located there to make such a sound. Only other motor related to HVAC I could think of would be blower resistor motors - having had those go on a previous BMW, it didn't make any sound, though. The result of the failure was simply spinning up/down of the fan speed randomly. I'm going with flaps. __________________ 2017 BMW 650xi Gran Coupe \| MSport \| Exec Package \| Driver Assist Plus \| ACC Stop & Go \| Adaptive Drive \| B&O \| Night Vision \| Cold Weather \| Active Seats 2015 Audi R8 V10 \| Brilliant Red on Black \| S-Tronic \| Carbon Sideblades \| Carbon Trim \| Full Leather \| Sport Exhaust \| Illuminated Doorsills \| I-Pod \| Contrast Stitching Previous: '14 550xi, '07 335i, '01 325i
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12-06-2019, 10:32 PM	#4
drewdogg77 Enlisted Member 2 Rep 37 Posts Drives: 2015 650i GC Join Date: Mar 2014 Location: tamarac florida iTrader: (0) Garage List 2011 BMW 550I [0.00]	when the car is off i dont hear anything, its only when ac is on and the temperature outside is around 73 degrees and below, the bmw tech said only thing it could be is the flap motors but he doesnt look to sure lol,,, but they would have to pull my dash out to replace the flap motors,,, hmmm a little sceptical about that tho,,,,
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12-07-2019, 09:59 AM	#6
thebmw Post Advisor 1631 Rep 1,692 Posts Drives: More Manuals than Automatics Join Date: Feb 2010 Location: Illinois iTrader: (10)	One of my 650s has a similar problem. When the heater is turned on (anything over 60 degrees on the temperature dial), it sounds like something is bubbling or an amplified water droplet sound. There is a rhythmic clunking as well that can even be felt in the steering wheel. I have cleared the cooling fluid lines and air bubbles. Although, someone suggested that there may still be a bubble stuck in one of the heating core valves. Others have suggested that a bearing in the heating core is bad. Not sure which one. Not worth the 10+ hours getting to the heating core to find out. I just turn on the heat to full, heat up the cabin, then turn it off.
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