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noisy blower motor on high


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Greetings, I would want to inquire whether anybody has encountered a boisterous blower motor when operating at its maximum settings. At lesser speeds, the sound is typical, but as the speed increases, a loud noise may be heard coming from behind the dashboard. Please inform me whether anybody has encountered this issue and if disassembling the blower motor for inspection is a complex task.

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Hello, Removing the blower motor requires great care and precision. To begin, open the bonnet (hood) and locate the two strengthening tubes positioned at the top of the engine bay, extending from under the windscreen plastic scuttle panel to each of the strut tops. Start by removing the plastic trim in the right-hand corner that is adjacent to the windscreen.Subsequently, you will have the capability to detach the right-hand strengthening tube that connects to the strut top.

Presented before you is a sizable lid with a flat, box-like structure.The dimensions are about 300mm x 200mm.There is a rough filter foam on the front side, as well as an AUC sensor.Exercise caution while handling the sensor, since its fastener is prone to easy breakage.To access the inside, it is necessary to detach the large lid by unscrewing the four torx screws.
It is advisable to clean the coarse filter. Once you remove the large lid, you will be able to locate the fan motor and the recirculating vent flaps. These vent flaps are not secured and just rest in place. Furthermore, at the termination of the vent flaps, there are driving gears that, if detached, must be reinstalled in the correct orientation to ensure the complete opening and closing of the vent.
It is advisable to lubricate the bearings of the motor shaft, provided that they are not sealed bearings. This may be done by applying mild oil to the ends of the shaft.Avoid excessive application of oil, as it may result in an unpleasant odour inside the vehicle. Additionally, please note that the end-of-line resistor is located in that area.
Inspect the fan blades for any abrasions that might potentially cause it to get entangled.
Do not activate the fan without the box cover attached.
Another plausible explanation for the noise might be that an object has been accidentally put into an air vent. The low setting of the fan may not have sufficient strength to dislodge it, but the high setting could be more effective.
It is advisable to remove the lid of the pollen filters box and take out the pollen filters. Then, increase the fan speed.The pollen filters are changed during maintenance, and if they are not reinstalled properly, they may get disturbed.

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The blower motor only draws air via the coarse foam filter located on the front side of the heater motor box. This foam filter effectively prevents the passage of any particles visible to the human eye.Any dust particles that manage to get through are effectively blocked by the more refined pollen filters. The dashboard outlet vents are the only potential entry point for foreign objects in the system.
The motor itself might be the cause, but it is unexpected for it to squeal at all speeds. However, increasing mileage increases the likelihood of this possibility.
If you decide to remove the motor for replacement, I recommend taking photographs using your mobile phone and using correction fluid or a marker pen to clearly label the drive wheels and other relevant components.
Wishing you success.

Edited by IrvesBMW
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The potential issue might be the coarse filter that safeguards the blower motor located in the engine compartment. The filter may become fragile and fracture, causing the fragments to generate an unusual buzzing sound when they are torn, thrown, and shattered towards the upper section of the blower mower.

It is advisable to verify if the coarse filter is deteriorating and whether it is the underlying cause of your problem.

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There is an excellent video on YouTube demonstrating the process of accessing and replacing this coarse filter. The video is intended for a f01 7 series, however, our F06/f12/f13 HVAC blower is configured in a similar manner. I will attempt to locate the video and provide it in this location.

EDIT: I located the movie, created by a former acquaintance from the e38 Bimmerboard forum era, namely Edwin from the Netherlands. In addition, he captured the audio emitted by the blower at the start of the video, which might potentially aid in identifying if it corresponds to the sound the original poster (OP) is experiencing. Subsequently, he proceeds to demonstrate the process of accessing and removing the cover.


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Yes. I completed this task a fortnight ago. The same bothersome sound persists when the fan speed is increased to 4 or higher. Disassembled the blower and surprisingly discovered a solitary desiccated leaf resting in the blower spindle. Reassembling it resolved the problem. The leaf entered because the inadequate filter had completely deteriorated. Acquired a fresh housing lid from the dealer, which includes a revamped filter (the new one is white). However, I have not yet installed it.

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One may easily browse any of the online part database websites to get the part number for the cover using a coarse filter. The HEATER/AC schematics will provide the information.

    The website <www.realoem.com> is a valuable resource.
    The website address is www.bimmercat.com.
    The website address is www.bmwfans.info.

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Here is a video showing the removal of the whole blower housing from an F07/F10. I am pleased that I saw this particular video, since it clearly demonstrates the precise placement of the blower resistor, which is located at the bottom of the fan housing. I was informed that it was located under the dashboard and would have required disassembling the lower section of the dashboard to access it.

I regret not being aware of this information prior to my recent engagement in the task of replacing the fan over the weekend. Consolidating the task and completing it in its entirety with the arrival of the resistor next week would have been a time-saving measure for me. However, I am now capable of completing the task within a time frame of 30 to 40 minutes.

This clearly demonstrates the significant profits that the thieves get from repairs.


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