The timing belt: focus on this essential element

We often hear about the timing belt at the mechanic's, and when it comes to replacing it, the cost of the intervention can be a really bad surprise. In this review, we examine the subject in 4 questions.

What is the purpose of the timing belt?

The timing belt is the engine's conductor. It is found on most car engines, commercial vehicles and other vehicles and synchronises the rotation of the crankshaft with the opening of the various valves.

Its role is essential, as the movement of the pistons in an engine must be perfectly coordinated with the intake of fuel and the exhaust of burnt gases. The timing belt of a car can be found on both diesel and petrol engines.

Why should it be replaced?

The timing belt is a "wearing" part that needs to be changed once or twice during the life of the vehicle. It is made of a very strong fibre structure and synthetic rubber. When subjected to high forces, temperature changes and ageing, the rubber loses its original properties and the belt can break.

It is important to change the belt before it breaks. Indeed, in most engines, when the valves are no longer synchronised, the pistons hit it directly and the damage is severe, and sometimes you cannot repair it.

Accessory belt and timing belt: what is the difference?

They are often misidentified and yet the accessory belt has nothing to do with the timing belt of a car. The accessory belt is used, as its name suggests, to drive the engine's accessories: alternator, air conditioning compressor, power steering pump, etc. It is a trapezoidal belt that can be seen when you open the bonnet. The timing belt, on the other hand, is flat, toothed and protected behind a fairing.

Are there engines without any timing belt?

Some engine models do not have a timing belt. In fact, there are two other types of timing:

Chain timing: the belt is replaced by a chain which has the advantage of not being a wearing part and it is therefore not necessary to replace it during the life of the engine.
Sprocket cascade timing: there is no chain or belt. The rotation of the engine is synchronised with the valves via a multitude of sprockets that transmit the movement. There is no need for preventive replacement either.

You now know everything about the timing belt! If you plan to replace the belt yourself, you will certainly need to delete the maintenance reminder. To save you time and money, Icarsoft France offers you diagnostic tools adapted to your vehicle.