When to Replace your Timing Belt
When to replace your timing belt is determined by the manufacturer of your vehicle. The owners handbook that came with the car will show all the required servicing intervals and the timing or cam belt change will be shown there. First change of the timing or cam belt will fall at around 50 - 60 thousand miles as shown on your odometer. This will vary somewhat dependant upon the vehicle in question.
The timing or cam belt is a rubber and fibre loop that actuates the valves on the top of your engine via a camshaft. Drive is taken from a pulley that is usually at the lower end of your engine. Because the actuation of the valves in a certain sequence is very important you can see that having a cam or timing belt in good condition is vital.
The belt is tightened into place by tensioners, these have a small pulley within them. These also wear, so you may consider changing these at the same time you change the timing or cam belt. It does add to the cost of the repair, but if they misfunction outside of the normal cam belt change cycle you will incur additional repair costs.
Not replacing your cam or timing belt at the right time means that you are open to massive repair costs should the belt fail. It is sometimes a hard call because with modern multi valve engines, a belt change can be a costly exercise. Most of this cost is due to labour charges because so much within the engine bay has to be removed to gain access to the belt itself. However, not changing the belt means that should it fail, you will be facing a top engine rebuild due to bent valves or worse.
Some manufacturers claim their engines to be non interference engines. This means that should the cam or timing belt fail, less damage is incurred as a result of that failure. However, even in these cases, some damage does incur, as you will still have to replace broken rockers and other parts designed to break to prevent more serious damage.
Should you be buying a second hand car, make sure you inspect any documentation that comes with it. Look for proof that the cam or timing belt has been changed if the cars mileage is near or over the manufacturer's belt change criteria. If there is any doubt as to the belt being changed, factor the cost of a belt change into the buy price of the vehicle. If the seller does not wish to lower the price of the car due to needing a belt change, then walk away as you must have this done.
It is quite feasible to change the cam or timing belt yourself, which will of course bring the cost of the work down considerably. However, be prepared for a lot of work, and make sure you set the timing up properly. If you are not sure how to do this then either call on the help of a more experienced friend, or have the work done professionally. If you do decide to do the work yourself, do not skimp on parts, the replacement belt you buy must be an OEM part otherwise you risk premature failure.
