Accessory Drive Belt Concerns

WARNING: This page is about a different car, the 2013 Ford Focus. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Do not lubricate the accessory drive belt, accessory drive belt tensioner or idler pulley(s) as potential damage to the accessory drive belt material construction, accessory drive belt tensioner damping mechanism, accessory drive belt tensioner pulley bearing and idler pulley(s) bearing may occur.

Cracking

Accessory drive belts are made from rubber which hardens with time and can develop cracks. As the accessory drive belt runs on the back of some of the pulleys, the cracks are opened up. Small cracks are not considered to be a failure of the accessory drive belt. Only if the crack is deep enough to reach the bottom of the groove to expose the cord or any chunks are found to be missing from the accessory drive belt, is the accessory drive belt condition considered to be unacceptable.

Check the accessory drive belt for cracks. If the damage exceeds the acceptable limit, install a new accessory drive belt.
Refer to: Accessory Drive Belt .

Chunking

Chunking describes the condition where long lengths of rubber become detached from the ribs of the accessory drive belt. This is considered to be a failure of the accessory drive belt.

Fig 1: Identifying V-Ribbed Serpentine Belt With Chunks Of Rib Missing
Check the accessory drive belt for damage. If any chunks are found to be missing, install a new accessory drive belt.
Refer to: Accessory Drive Belt .

Pilling

Pilling is dust that forms in between the ribs of the accessory drive belt from rubber that is worn off the accessory drive belt when it is new. There may also be loose particles left on the accessory drive belt during the manufacturing process. These are worn off and form into small balls of rubber that then get trapped in the grooves of the accessory drive belt. This condition will usually clear itself within 4800 km - 8000 km (3000 miles - 5000 miles) of normal driving.

Fig 2: Identifying V-Ribbed Serpentine Belt With Piling
Check the accessory drive belt for pilling. The condition of the accessory drive belt should be compared against the illustration.
1. Small scattered pills. Not considered a concern. No action required.
2. Small scattered pills. Not considered a concern. No action required.
3. Longer pills up to 50% of the rib height. Possible noise concern. INSTALL a new accessory drive belt if noise is apparent.
  Refer to: Accessory Drive Belt .
4. Longer pills up to 50% of the rib height. Possible noise concern. INSTALL a new accessory drive belt if noise is apparent.
  Refer to: Accessory Drive Belt .
5. Heavy deposits in the grooves. Possible noise and stability concern. INSTALL a new accessory drive belt.
  Refer to: Accessory Drive Belt .
6. Heavy deposits in the grooves. Possible noise and stability concern. INSTALL a new accessory drive belt.
  Refer to: Accessory Drive Belt .
Incorrect fitment

Accessory drive belt noise can be generated by the accessory drive belt being incorrectly fitted on the pulley as shown in the following illustration. Make sure that all the V grooves on the accessory drive belt contact correctly with the pulley.

Fig 3: Identifying Drive Belt - Incorrect Installation Position

If the cause is not visually evident, verify the symptom and refer to the Symptom Chart.

SYMPTOM CHART

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: Accessory Drive 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: Accessory Drive 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 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). Accessory drive belt idler pulley bearing failure.	REMOVE the accessory drive belt. Refer to: Accessory Drive Belt . INSPECT the idler pulley(s) for surface finish. INSTALL a new idler pulley(s) as necessary. TEST the system for normal operation. REMOVE the accessory drive belt. Refer to: Accessory Drive 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. Loose components or hardware.	CHECK the accessory drive belt tensioner for correct operation or damage. REFER to the Accessory Drive Belt Tensioner in Component Tests . INSTALL a new accessory drive belt tensioner as necessary. TEST the system for normal operation. 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.