Replacing the toothed belt – do it yourself step-by-step!


Changing the toothed belt – that’s how it works!

What does a toothed belt do and how do I know that it is defective? How do I change a timing belt? Here’s the info and step-by-step instructions. But be careful, doing this repair yourself is only for very experienced mechanics. If you are unsure, we advise you to visit a specialist workshop.

What does the toothed belt do and how do I recognize a defect?

The toothed belt, sometimes called the timing belt, is the connection point between the camshaft and crankshaft and ensures the transmission of power between these two components. It is a band of rubber and plastic with teeth on the inside – hence the name ‘toothed belt’. This tooth structure allows the toothed belt to grip better and transmit higher forces.
Recognizing a defect in the toothed belt is not so easy, as it is not noticeable with noises like many other defects. If you can hear a squeaking, this can be not only the ribbed V-belt but also the deflection and tensioning pulleys that can be found on both the toothed belt and the ribbed V-belt. These deflection and tensioning pulleys must then be replaced, and at the same time the toothed belt or the V-ribbed belt. Otherwise there is no indication of a toothed belt defect – at some point individual parts will simply fly in your face. That is why the following note is all the more important.

Important: Observe change intervals! The main materials of the timing belt, rubber and plastic, make the timing belt quieter than an iron timing chain, but the material eventually fatigues and wears out. Regular visual checks of the toothed belt are therefore absolutely necessary in order to detect defects at an early stage. If the timing belt breaks, it can cause major damage to the engine. And even if the timing belt still appears to be in good condition, after five to six years at the latest it is time for a change. However, this varies from manufacturer to manufacturer, which is why you should definitely refer to the service specifications of your car manufacturer.

What do I need to change my timing belt?

  • The right timing belt
  • jack
  • locking tool
  • ratchet set
  • Various screwdrivers
  • nut set
  • possibly also torx

Tip: The best way to find the right timing belt is to consult your car’s operating instructions. Alternatively, you can also have the correct timing belt searched out at a workshop you trust using the chassis number of your car!
When changing the toothed belt, it is also a good idea to check the seals and replace them if necessary. In addition, the tension and idler pulleys and the water pump should also be replaced. There are complete toothed belt sets that contain all the necessary parts.

danger: This is a fairly specific guide and will not apply to all models. The very fact that there are so many variations makes it almost impossible to write a universal repair guide; In addition, this is a very demanding repair that should only be carried out by experienced mechanics on their own. Nevertheless, we hope that this guide can be of some help to you.

Step-by-step instructions – changing the toothed belt

  1. First disconnect the engine battery.
  2. In order to be able to remove the old timing belt and install the new one, you need space around the timing belt; the toothed belt is on the engine, which is why you have to dismantle the engine cover, the intake ventilation and then the air filter.
  3. As soon as you have removed these components, you may have to remove the reservoir with the power steering fluid, then the cooling water reservoir, and various connectors. Depending on the vehicle model, the toothed belt is under a plastic cover, which you must of course also remove. You should now have exposed the toothed belt.
  4. Slide the jack under the engine and raise it until it touches the engine – do not jack the engine and make sure the jack is positioned properly!
  5. Now you have to dismantle the bearing block and the motor mount as well as the plastic cover; once these components are removed, the engine is held only by the jack.
  6. In order to be able to remove the old timing belt now, you have to find a mark that is on the lower pulley. There is a matching mark on the housing for it. Rotate the bottom pulley until the marks align. This way you can first use the locking tool that prevents twisting. The locking tool is inserted into one of the camshaft gears at the top.
  7. Now you can loosen the first tensioner to remove the toothed belt. But before you can do that, you have to hold and unscrew the lower part of the pulley, and still unscrew and remove the lower part of the timing belt cover.
  8. The toothed belt can now be completely removed.
  9. Before you install the new timing belt, it is a good idea to replace the water pump.
  10. Before you can do that, however, you must first drain the water pump; there is a drain cock on the water pump for this.
  11. Then loosen the screws of the water pump bracket and pull out the water pump. We might need something tasty here. Then you can immediately install the new water pump.
  12. Before installing the new toothed belt, the deflection rollers and the tensioning roller must also be replaced.
  13. Now you can put on the new toothed belt.
  14. Finally, you must reassemble all the parts in reverse order. Don’t forget to take a test drive to verify that the repair was a success.
  15. If you did that – congratulations! – you’ve managed a pretty tedious repair!

A job that you can do yourself with skill and experience. And you save a lot of money! It is best to also look around in the ATP car parts online shop for cheap new timing belt sets suitable for your car model. However, if you notice that your screwdriver skills are not sufficient, it is better to go to a workshop you trust. And if your ATP spare part is installed, you have at least saved there.

Have you ever done a repair like this yourself? Do you have any other tips for other readers? Write us your experiences in the comments!

Good ride!
Your ATP team


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