What Causes the Abnormal Noise in Side Curtain Airbags?
2 Answers
Most common abnormal noises in side curtain airbags depend on the engine's rotational speed state. Several scenarios of abnormal noise: Noise occurs only at idle or low-speed operation. Possible causes include: excessive clearance between piston and cylinder wall; overly tight piston pin or connecting rod bearing assembly; excessive clearance between tappet and its guide hole; wear on the camshaft profile; sometimes, a loose starter causing pulley noise (noticeable during speed changes). When maintaining a certain speed, the noise becomes chaotic, with brief sounds emitted during rapid deceleration. Possible causes include: cracked camshaft timing gear or loose fixing nut; broken crankshaft; loose piston pin bushing; excessive axial clearance of the camshaft or loose bushing. Noise appears during rapid acceleration and persists during high-speed operation. Possible causes include: loose connecting rod bearing, melted or mismatched bearing shell; loose crankshaft bearing or melted bearing shell; broken piston pin; broken crankshaft. Relationship between noise and temperature: Noise occurs at low temperatures and diminishes or disappears as temperature rises. Possible causes include: excessive clearance between piston and cylinder wall; piston issues due to inaccurate depth and width of main bearing oil groove; low oil pressure leading to poor lubrication. Noise appears after temperature rises and diminishes or disappears when temperature drops. Possible causes include: premature ignition due to overheating; opposite orientation of the major and minor axes of the piston skirt ellipse; insufficient piston ovality, excessively small clearance between piston and cylinder wall; deformed piston; excessively small piston ring clearances.
The rattling noise from the side curtain airbag is indeed concerning. Based on my experience, there are several common causes. Loose components are the primary issue - for instance, unfastened bolts securing the airbag can create metallic squeaking sounds during daily bumps. Material aging is another factor, particularly when the plastic or rubber edges of the airbag harden and produce creaking noises when compressed. Improper installation sometimes occurs when technicians neglect lubrication during new vehicle assembly or post-accident repairs, leading to rusted metal contact points. Although rare, electronic control system malfunctions can also cause noises if sensor vibrations transmit to the airbag structure. I recommend visiting a professional workshop immediately to check bolt tightness and apply lubricant. Ignoring these sounds may delay airbag deployment during collisions - safety should never be compromised.
