1994-2002 [Subscribe to Daily Digest] |
S.I. # 854-2143
June 1999
Noise from A/C system
Cars affected
Saab 900 M94 M98
Background
This SI is intended to prevent unnecessary repairs while ensuring the correct cause of the fault is rectified.
Various types of noise may be heard from the A/C system. Some of these are normal and others can occur in the event of a malfunctioning expansion valve, antifrost thermostat or compressor.
Antifrost thermostat malfunctions on cars within VIN intervals T2037750 - W2019950 (3D/5D) and T7010027 - W7008292 (CV) have caused a large number of compressor breakdowns. It is essential to make sure the antifrost thermostat on cars within the above VIN range is fitted with a white plastic clip instead of a metal one. It is also necessary on these cars to replace the thermostatic switch on the compressor as its service life is limited by the number of times it is activated. This number will increase if there is a malfunction in the antifrost thermostat, which will cause the compressor to break down.
Parts required
50 45 976 Antifrost thermostat (CA: 30581274)
43 83 824 Thermostatic switch Seiko-Seki up to and
including VIN S2002729 (3D/5D) and S7013039 (CV) (CA: 30550728)
46 32 014 Thermostatic switch Seiko-Seki from VIN S2002730 (3D/5D) and S7013040 (CV) (CA: 30557509)
50 45 166 Expansion valve (CA: 30576226)
Symptoms, Identifying different noises
The following list can be used to aid the identification of different noises and their possible causes.
1. It is normal to hear a noise from the compressor's electromagnetic clutch when it engages, provided there is correct play. See Service Information 854-1427 for Saab 9000.
2. A hissing sound coming from the evaporator like steam being released from the system is completely normal (but can be amplified if the expansion valve is malfunctioning).
3. Rattling is caused by A/C pipes touching the body, especially under the battery tray.
4. A very high frequency howling sound occurring when the compressor starts or is engaged. The sound can be heard best at approx. 70 km/h in fifth gear (1800 - 2000 rpm) or when stationary after the engine has been running for a few minutes. The cause is the expansion valve.
5. A repetitive humming sound that is not dependent on engine speed or vehicle speed is caused by the expansion valve.
6. High frequency whistling caused by the expansion valve.
7. A metallic sound heard from the compressor can be caused by internal damage.
posted by 216.164.137...
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
