Timing Belt and Sprockets

Inspect both sides of the timing belt. Replace the belt with a new one if any of the following conditions exist:

Hardening of the rubber-back side is glossy without resilience and leaves no indentation when pressed with a fingernail
Cracks on the rubber backing
Cracks or peeling of the canvas backing
Cracks on rib root
Cracks on belt sides
Missing teeth or chunks of teeth
Abnormal wear of belt sides: the sides are normal if they are sharp, as if cut by a knife
If none of these conditions exist, the belt does not need replacement

Check for premature parting of the belt

Check if the teeth are cracked or damaged

Look for noticeable cracks or wear on the belt face

You may only have damage on one side of the belt; if so, the guide could be the culprit

Foreign materials can get in between the teeth and cause damage

Inspect the timing belt for cracks, fraying, glazing or damage of any kind

Damage on only one side of the timing belt may indicate a faulty guide

ALWAYS replace the timing belt at the interval specified by the manufacturer