Ask Dan! – What Does My Timing Belt Do?

“What does my timing belt do, and why is it such a big deal to replace it?”

A Technical Description

The timing belt keeps the upper and lower half of the engine moving in sync. It connects the crankshaft (lower half) to the camshaft (upper half). The crankshaft control the movement of the pistons and the camshaft controls the opening and closing of the valves. If these get slightly out of sync the car can knock, run very poorly, or not run at all. If the timing belt breaks or slips, the car will not run and may potentially damage the engine. Regularly replacing the timing belt helps to ensure the belt won’t break which keeps the engine running and prevents costly engine damage.

Timing Belt Configuration

A Timing Belt is Like the Conductor of a Symphony

Think of it this way: A smooth running engine is like a symphony. There are many pieces that have to work together in perfect harmony. The timing belt is like the conductor that makes sure that every piece of the orchestra is playing its part at just the right moment. If the conductor were to walk off the stage during the middle of the song, it would be impossible for every member of the orchestra to make their entrance at the correct moment. The result? The symphony falls apart. Everyone will likely play their part at the wrong time, creating a train wreck of a sound and then… stop. If the timing belt breaks, the internal parts of the engine no longer work in perfect harmony and the symphony of the engine…stops.
Why Does it Cost So Much to Replace It?
The biggest cost in replacing a timing belt is the labor involved. The timing belt is usually located in an area that requires that many other components be removed before the timing belt can even be reached. Another contributing factor to the cost is the number of other parts that are typically replaced when the timing belt is done. Because the timing belt runs on a number of pulleys, tensioners, and (usually) the water pump, it is prudent to replace these items at the same time the timing belt is replaced. Think of it this way: You wouldn’t want to pay for 5 hours of labor to replace the timing belt, and then find out six months later that the water pump is leaking and that you now have to pay another 5 hours of labor to replace the water pump that was located in the same area as the timing belt. Replacing all those parts at the same time can save quite a bit of money on future labor costs.
Have a question for Dan?  Ask it here or send it to
Dan Amundsen is a Master ASE Certified Technician, with over 40 years of automotive repair experience.  He has been the owner of Juanita Firs 76 since 1978.  He runs a true family business with his two children, three nieces, and many just-like-family employees that have been with the company for over 15 years.

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