A/C - Blower Motor Howling/Whistling Noise
SI B 64 01 05October 2006
Heating and Air Conditioning
Technical Service
This Service Information bulletin supersedes S.I. B64 01 05 dated August 2005.
[NEW] designates changes to this revision
SUBJECT
Blower Motor Howls and/or Whistles
MODEL
E90, [NEW] E91 (3 Series) Vehicles produced to March 31, 2006
[NEW] SITUATION
A whistling noise can be heard from the ventilation system under the following conditions:
- Control panel set to "AUTO" mode
- Blower speed set to 4 or higher
- Vehicle heated up
- Set temperature of over 72 F.
[NEW] CAUSE
- Blower motor corrosion caused by water ingress
- Contact between the Heater/Air Conditioner and support tube
- Whistling at the air blending flap
- Whistling at the mixed air flap
- Whistling at the demister flap
[NEW] PROCEDURE
Inspect the blower for evidence of water or rust, also in the area of the thrust bearing. If the blower is corroded it must be replaced.
If water ingress is detected use the following procedure
1. The area around the cowl trim must be checked for leaks. If necessary replace the cross member sealing strip and the retaining strip for the cowl panel trim. Refer to the following Repair instructions:
- RA 5113117 Replace the cowl panel trim
- RA 5131... Remove and refit/replace the retaining strip for the cowl trim
2. It is also necessary to check that the upper part of the microfilter housing is fitted correctly.
3. Check that the gap (A) between the upper microfilter housing and cowl is no more than 1cm. Remove and reposition housing as necessary to reduce the gap.
If no water ingress can be detected use the following procedure
1. Remove the instrument panel and check the clearance between the Heater-Air Conditioning housing and the support tube. At the area between the fresh-air flaps and the defroster flaps using a sheet of paper.
2. It must be possible to slide the sheet of paper between the Heating-Air Conditioning housing and the support tube (3).
3. See the second illustration to the left for a cross-sectional view of checking the clearance.
4. If the sheet of paper does not slide through and the Heating-Air Conditioning housing is contacting the support tube, fit a washer (8x23x1mm) at each fastening point (1).
5. Once the clearance has been restored, warm up the Heating-Air Conditioning system for approximately 60 minutes to a set temperature of 79 F. Check to see if the whistling noise still occurs.
6. If the noise still occurs, replace the Heating-Air Conditioning housing. Refer to EPC for the proper part numbers. After a new housing has been installed recheck the clearance between the Heating-Air Conditioning housing and the support tube and correct as necessary.
PARTS INFORMATION
WARRANTY INFORMATION
Covered under the terms of the BMW New Vehicle Limited Warranty.
Part Number Description Quantity
Defect Code Refer to KSD
Labor Operation: Refer to KSD
Labor Allowance: Refer to KSD
Disclaimer