Symptom Chart

WARNING: This page is about a different car, the 2015 Ford Focus. However, it is still accessible from the selected car via links, so may be relevant.

Symptom	Possible Sources	Action
Accessory drive belt noise	Accessory drive system	CHECK the system with the engine running and the accessory drive belt removed (only run the engine for a very short period). If a noise is apparent, the cause is not the accessory drive system. If a noise is not apparent, the cause is the accessory drive system. CHECK where the noise is coming from. Use a stethoscope or other listening device to determine the source of the noise. INSTALL new components as necessary. TEST the system for normal operation.
Accessory drive belt incorrectly installed.		CHECK the accessory drive belt is correctly installed in the pulley grooves. INSTALL a new accessory drive belt as necessary. Refer to: Air Conditioning (A/C) Compressor Belt . TEST the system for normal operation.
Pulley(s).		CHECK the pulley(s) for damage, freedom of rotation, stone entrapment and alignment. INSTALL new components as necessary. TEST the system for normal operation.
Lubricant or other contamination.		CHECK the accessory drive belt for contamination or damage. RECTIFY the source of the leak and INSTALL a new accessory drive belt. Refer to: Air Conditioning (A/C) Compressor Belt . TEST the system for normal operation.
NOTE: Squeal is defined as a continuous shriek, most noticeable when the engine is being accelerated or with electrical load. Accessory drive belt squeal	Accessory drive belt tensioner worn, damaged or contaminated with oil.	CHECK the accessory drive belt tensioner for correct operation, damage or contamination. REFER to the Accessory Drive Belt Tensioner Component Test in Component Tests . INSTALL a new accessory drive belt tensioner as necessary. Refer to: Accessory Drive Belt Tensioner . TEST the system for normal operation.
NOTE: Whine is defined as a continuous noise at the same frequency, generally associated with plastic pulleys. Accessory drive belt whine	Poor surface finish on accessory drive belt idler pulley flat surface(s).	REMOVE the accessory drive belt. Refer to: Air Conditioning (A/C) Compressor Belt . INSPECT the idler pulley(s) for surface finish. INSTALL a new idler pulley(s) as necessary. TEST the system for normal operation.
Accessory drive belt idler pulley bearing failure.		REMOVE the accessory drive belt. Refer to: Air Conditioning (A/C) Compressor Belt . INSPECT the idler pulley(s) for smooth rotation. INSTALL a new idler pulley(s) as necessary. TEST the system for normal operation.
NOTE: Chirp is defined as a twittering noise, often intermittent Accessory drive belt chirp	Pulley misalignment (usually evident at idle).	CHECK that the accessory drive belt is running centrally on the flat pulleys. TEST the system for normal operation. CHECK the pulleys for excessive end float and bent flanges. With the engine running at idle, use a stethoscope to identify the source of the noise. INSTALL new components as necessary. TEST the system for normal operation.
NOTE: Rattle is defined as a metallic knocking noise Accessory drive belt rattle	Accessory drive belt tensioner hitting the end stops.	CHECK the accessory drive belt tensioner for correct operation or damage. REFER to the Accessory Drive Belt Tensioner Component Test in Component Tests . INSTALL a new accessory drive belt tensioner as necessary. TEST the system for normal operation.
Loose components or hardware.		CHECK the components or hardware for correct installation and tighten as necessary. TEST the system for normal operation.
Accessory drive belt fraying	Accessory drive belt. Pulley(s).	CHECK the extent of the fraying by referring to the illustrations shown in the Visual Inspection in Inspection and Verification . Only INSTALL a new accessory drive belt if the fraying is within the criteria quoted in the Visual Inspection in Inspection and Verification . TEST the system for normal operation. CHECK the pulley(s) for damage, freedom of rotation and alignment. INSTALL new components as necessary. TEST the system for normal operation.