Engine Timing and Accessory Drive Guides

Part of the Engine and engine management guides.

A timing belt or chain job is decided by the kit contents, not by the belt. These guides cover what a timing kit actually includes, how the replacement interval is set, which tensioner and pulley hardware belongs with it, and how failure presents. They are written for the person who has to quote the job and then stand behind it.

Timing kits and replacement intervals

Kit contents vary by engine. Read the bill of materials before comparing two quotes.

• Timing Belt Kit Contents Vary by Engine—Read the Bill of Materials
• How Often Should You Replace a Timing Belt Kit?
• Timing Chain Kit Supplier: Reliable Aftermarket Engine Timing Solutions for Auto Parts Businesses
• What are the signs and cost of timing belt failure?

Tensioners, pulleys and dampers

The hardware around the belt is what usually fails first, and it is bought separately unless the kit says otherwise.

• How Do Torsional Damper Springs Eliminate Gearbox Rattle?
• What Is a Belt Tensioner and Why Is It Critical for Car Accessory Drive Systems?
• What Is a Pulley on a Car?
• What Is a Tensioner Pulley?

Frequently asked questions

Does a timing belt kit include the water pump?

Sometimes. It depends on the kit and the engine — the part number and bill of materials decide. Check the contents rather than assuming, especially on engines where the water pump is driven by the timing belt.

How often should a timing belt be replaced?

Follow the manufacturer’s interval for that engine, then shorten it if the vehicle sees severe duty. Mileage alone is not enough: age, heat cycles and contamination all affect belt life.