Timing Belt: Inspection

Inspect the belt closely. If the following problems are evident, replace the belt with a new one.
1. Hardened back surface of rubber
  Back surface is glossy, non-elastic and so hard that when the nail of your finger is pressed into it, no mark is produced.
  
  Fig 1: Checking Timing Belt Hardness
  Courtesy of HYUNDAI MOTOR CO.
2. Cracked back surface of rubber.
  
  Fig 2: Checking Timing Belt For Cracks
  Courtesy of HYUNDAI MOTOR CO.
3. Side of belt is badly worn.
  NOTE: A belt in good condition should have clear-cut sides as if it were cut with a sharp knife.
  
  Fig 3: Checking Timing Belt Condition
  Courtesy of HYUNDAI MOTOR CO.
4. Teeth are badly worn out.
  Initial stage: Canvas on load side of the tooth flank worn (fluffy canvas fibers, rubber gone, color changed to white, and unclear canvas texture)
  
  Last stage: Canvas on the load side of the tooth flank worn down and rubber exposed (tooth width reduced).
5. Missing tooth
  
  Fig 4: Checking Timing Belt For Tooth Wear
  Courtesy of HYUNDAI MOTOR CO.
If backlash or an irregular noise is observed when rotating the pulley, replace the timing belt tensioner and idler pulley.

Fig 5: Checking Timing Belt Tensioner Condition
Courtesy of HYUNDAI MOTOR CO.