Timing Belts – Connect Parts Together, To Operate In Sequence

Timing Belts - Connect Parts Together, To Operate In Sequence
Timing Belts - Connect Parts Together, To Operate In Sequence

Timing belts have replaced timing chains, in most of the vehicles on the road today.

And, this belt, is totally different, from “V-belts” or “Serpentine belts”.

Because, this belt performs, a much more important job. First, the belt, provides a connection, between the camshaft and crankshaft. Consequently, allowing the pistons and valves, to operate in proper sequence.

Timing belts have proven to be, quieter and more efficient, than timing chains.

But, those benefits come at a cost. Consequently, they require more frequent replacement, than timing chains. Because, they have a shorter lift span than other parts. Furthermore, the timing belt, is responsible for synchronizing, the engine’s many functions.

And, may also include, running the water pump. Most timing belts cannot be seen, by just looking under the hood. Because, they are usually hidden by plastic or tin covers. And, that is another good reason, to follow your owners manual for replacement.

Engine Timing Belt
Engine Timing Belt

First, it controls the rotation, of the camshaft and crankshaft. And, the opening and closing, of the engine’s many valves. So, when all this is done, it allows the fuel, to ignite in the combustion chamber, at the right time. In order for this process to take place, the valves, have to open and close, at the right time.

If You Replace The Belt, Replace The Water Pump At The Same Time

When your timing belt needs replacement, it usually makes sense to also replace the:

  • Water pump
  • Tensioners
  • Pulleys
  • Gaskets

All at the same time as the belt. However, in some systems, a timing chain or a fan, drives the water pump. But, in most cars, the timing belt does all the work. So, why change the water pump at the same time. Essentially, time and labor costs.

Replacing Belt And Water Pump
Replacing Belt And Water Pump

Your belt or chain, may only have a few thousand miles left on it. And, if the water pump fails, you’ll be doing much of the same work, all over again. So, save time and money, and combine your auto repairs, wherever possible. Finally, for many vehicles there are complete kits, that include every thing you need. This also works, in reverse. So, if the water pump goes, replace the belt.

Consequences Of Wrong Engine Timing

If the timing is wrong, the valves can open, when the pistons are at the top of the cylinder. As a result, your engine can suffer anything from, bent valves to a broken piston. First, you will have to disassemble, the top part of the engine. Before, you actually know, the full extent of the damage. That’s why, the valves and pistons, have to be in the correct position, at the right time.

There Are Two Types Of Engines, That Use A Timing Belt:

Best know as, Interference and Non-interference engines.

Free-running Engine (non-interference)

If the belt breaks on a “free-running” design, the engine will just stop. There is enough clearance, between the pistons and valves, so no mechanical damage usually occurs. So, it is possible, just replacing the belt, may fix your problem.

Interference Engine

Damaged Valves In Cylinder Head
Damaged Valves In Cylinder Head

But, if the timing belt breaks, on an “interference engine”, mechanical engine damage will occur. Most commonly, the damage is, the pistons hitting open valves. Resulting, in the need for expensive repairs. In extreme cases, replacing the engine may be required.

Piston Damage
Piston Damage

Breakage, is not the only reason to replace your timing belt. Looseness and wear, can allow the timing belt to slip. And, this is another form of belt failure. Furthermore, causing poor performance, no start conditions or engine damage.

So, proper maintenance requires timing belt replacement, at regular intervals, before it breaks or wears out. Therefore, the manufacturers provide, a replacement schedule and repair information for this critical component.

How do you know if your vehicle, has a timing belt? How do you know, when it should be replaced? Check out our (PDF) files or your owner’s manual to be sure.


So, timing belts are cheap, probably costing less than $30 at an auto parts store. But, your mechanic will probably charge, several hundred dollars (or more) for a belt replacement. Finally, with something as important as the belt, prevention is better than failure.

Thank You !