Ford Fiesta Quiz
Engine

Accessory Drive. Diagnosis and Testing

In this manual: Engine
Service Information — 27Suspension — 48Transmission — 9Brake System — 52Steering — 21Engine — 140Manual Transmission, Clutch, Transfer Case and Power Transfer Unit — 48Exhaust System — 6Fuel System — 21Climate Control System — 58Instrumentation and Warning Systems — 26Battery and Charging System — 20Infotainment Systems — 41Lighting — 29Power Distribution — 11Electronic Function Group — 30Body and Paint — 275Frame and Mounting — 3
2steps
~12min
1/5difficulty
Done 0 of 2

Inspection and Verification

  1. Verify the customer concern.
  2. Visually inspect for obvious signs of mechanical damage.

Visual Inspection Chart


  • Damaged or contaminated accessory drive belt
  • Damaged or contaminated pulley(s)
  • Damaged Tensioner
  • Incorrect accessory drive belt
  • Incorrect accessory drive belt installation
  • Generator
  • A/C compressor
  • Pulley(s)
  • Accessory
  1. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

Accessory drive belt concerns

NOTICE: Do not lubricate the accessory drive belt, as damage to the accessory drive belt material may occur.

Cracking

Accessory drive belts are made of rubber, which hardens over time and may develop cracks. Because the accessory drive belt runs over the back of some pulleys, the grooves are exposed. Small cracks are not considered an accessory drive belt fault. Only if a crack is deep enough to reach the bottom of a groove to expose the cord, or if any pieces are missing from the accessory drive belt, is the accessory drive belt condition considered unacceptable.

  1. Inspect the accessory drive belt for cracks. If the damage exceeds the limit, install a new accessory drive belt.
    Refer to: Accessory Drive Belt (303-05B Accessory Drive - 1.6 L EcoBoost (132 kW/180 L PS) - Sigma, Removal and Installation).

Chunking

Chunking describes a condition where long sections of rubber separate from the ribs of the accessory drive belt. This is considered a failure of the accessory drive belt.

  1. Inspect the accessory drive belt for damage. If any pieces are missing, install a new accessory drive belt.
    Refer to: Accessory Drive Belt (303-05B Accessory Drive - 1.6 L EcoBoost (132 kW/180 L PS) - Sigma, Removal and Installation).

Peeling

Peeling is dust that forms between the ribs of the accessory drive belt from rubber that wears off the belt when it is new. There may also be loose particles left on the accessory drive belt during the manufacturing process. These wear off and form small rubber balls that then become lodged in the grooves of the accessory drive belt. This condition usually goes away after 4800–8000 km (3000–5000 miles) of normal driving.

  1. Check the accessory drive belt for pilling. The condition of the accessory drive belt should be compared to the illustration.
    1. Small scattered pellets. Not considered a concern. No action required.
    1. Small scattered pellets. Not considered a concern. No action required.
    1. Longitudinal cracks up to 50% of the rib height. Possible noise concern. INSTALL a new accessory drive belt if noise is present.
      Refer to: Accessory Drive Belt (303-05B Accessory Drive - 1.6 L EcoBoost (132 kW/180 L PS) - Sigma, Removal and Installation).
    1. Longitudinal cracks up to 50% of the rib height. Possible noise concern. INSTALL a new accessory drive belt if noise is present.
      Refer to: Accessory Drive Belt (303-05B Accessory Drive - 1.6 L EcoBoost (132 kW/180 L PS) - Sigma, Removal and Installation).
    1. Heavy deposits in the grooves. Possible noise and stability concerns. INSTALL a new accessory drive belt.
      Refer to: Accessory Drive Belt (303-05B Accessory Drive - 1.6 L EcoBoost (132 kW/180 L PS) - Sigma, Removal and Installation).
    1. Heavy deposits in the grooves. Possible noise and stability concerns. INSTALL a new accessory drive belt.
      Refer to: Accessory Drive Belt (303-05B Accessory Drive - 1.6 L EcoBoost (132 kW/180 L PS) - Sigma, Removal and Installation).

Incorrect Installation

Accessory drive belt noise may be caused by the accessory drive belt being incorrectly installed on the pulley, as shown in the following illustration. Make sure that all the V-grooves on the accessory drive belt contact the pulley correctly.

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

Symptom Chart

Symptom Possible Sources Action
  • Accessory Drive Belt Noise
  • Accessory Drive System
  • Using a stethoscope or other listening device, locate the noise source. INSTALL new components as necessary. CHECK the system for normal operation.
  • Accessory drive belt incorrectly installed.
  • CHECK that the accessory drive belt is correctly installed in the pulley grooves. INSTALL a new accessory drive belt if necessary.
    Refer to: Accessory Drive Belt (303-05B Accessory Drive - 1.6 L EcoBoost (132 kW/180 L PS) - Sigma, Removal and Installation).
    CHECK the system for normal operation.
  • Pulley(s).
  • CHECK the pulley(s) for damage, free rotation, debris, grip and alignment. INSTALL new components as necessary. CHECK the system for normal operation.
  • Grease or Other Contamination.
  • CHECK the accessory drive belt for contamination or damage. CORRECT the source of the leak and INSTALL a new accessory drive belt.
    Refer to: Accessory Drive Belt (303-05B Accessory Drive - 1.6 L EcoBoost (132 kW/180 L PS) - Sigma, Removal and Installation).
    CHECK the system for normal operation.
  • NOTE: Chirp is defined as a often intermittent squeal.
  • Accessory Drive Belt Squeal
  • Pulley Misalignment (usually noticeable at idle).
  • CHECK that the accessory drive belt runs centered on the flat pulleys. CHECK the system for normal operation.
  • CHECK the pulleys for excessive axial play and bent flanges.
  • With the engine running at idle, use a stethoscope to locate the noise source. INSTALL new components as necessary. CHECK the system for normal operation.
  • NOTE: Rattle is defined as a metallic knocking noise.
  • Accessory Drive Belt Squeal
  • Loose Components or Equipment.
  • CHECK that components or equipment are correctly installed and tighten as necessary. CHECK the system for normal operation.

Test yourself

A quick Ford Fiesta quiz: every answer comes with an explanation and a link to the manual page.