What Causes the Squeaking Sound When Turning on the Heater?

[DelCarlos]

When turning on the heater in a car, the squeaking sound may be caused by foreign objects on the heater fan, leading to noise during blade rotation. Other possible reasons: Lack of lubrication or damage to the fan bearing; resonance caused by plastic components becoming hard and brittle due to extremely low temperatures; improper adjustment or detachment of the dynamic balancing weights on the fan blades. Solutions: Check the blower and air conditioning system for foreign objects, such as leaves or plastic packaging, which can produce similar sounds. Removing these objects will eliminate the noise. Inspect the condition of the fan bearing and add lubricant or replace the bearing if necessary. For noise caused by hardened plastic components due to low temperatures, no immediate action is needed—simply run the heater for about ten minutes to allow the plastic parts to warm up, and the noise will naturally disappear. Visit a professional repair shop to have the fan blades dynamically balanced. If any balancing weights have fallen off, they should be promptly reinstalled.