I notice that there were two service bulletins about the ticking noise at idle but I want to know how to fix it?
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2003 Oldsmobile Bravada Question: Ticking Noise at Idle
Answer #1lawrenceg October 20, 2009, 16:52Master
The only bulletin I found was for a ticking noise from the cooling fan clutch. Here is a brief description of this problem and fix. If your ticking noise doesn't exactly match these symptoms, then it is something else, and the source of the noise will need to be determined.
Some customers may comment on an underhood tick noise heard while the vehicle is idling. Technicians may find that the noise does not increase or decrease with changes in the engine idle RPM. The tick noise occurs at approximately one second intervals.
This condition may be caused by the electro-viscous fan clutch control function of the Powertrain Control Module (PCM) attempting to keep the fan speed between 300-600 revolutions per minute (RPM). At idle, the cooling fan speed will drag to approximately 500 RPM then oscillate between 300 and 600 RPM. When the fan speed drops below 500 RPM, the PCM will pulse the fan control solenoid. The pulsing of the solenoid is the cause of the ticking noise.