The main reason for replacing your timing belt before it has actually snapped is that this can prevent any additional internal damage to the engine. If the timing belt was to break while the engine was running then you run the risk of damaging the valves and pistons. This can result in a very expensive set of reapirs, and you still need to replace that timing belt anyway, so it is far better to replace it before it breaks!
Knowing when to replace your timing belt actually depends on the mileage of your car. Depending on the manufacturer, you may see recommendations for it to be replaced anywhere between 60,000 and 105,000 miles. It is best to call your local repair shop and ask for advice about replacing your timing belt. You can expect to pay in the region of $750-$1000 to have it replaced.
What if I Have a Timing Chain, Not a Belt?
If you have a timing chain then this will not require regualr interval replacement to maintain it because timing chains do not break. However, they can still wear out over time so if you are hearing a rattle or a whine under the hood it could be time to look at replacing the chain. Unfortunately, replacing a timing chain is more expensive at arounds $1000 – $1700, but in theory they should need repalced less often so it does balance out.
Your car’s water pump is actually driven by the timing belt, so a good step toward preventative maintenance is to replace the pump at the same time as your timing belt. If your water pump was to develop a leak after you have the timing belt replaced then your mechanic is essentially going to have to carry out the exact same repair in order to replace the pump, so it makes sense to replace them both simultaneously. No-one wants a double bill!
Even if you are a little lax about regular car maintenance, finding out when your timing belt is going to need replaced is a good way to avoid needless expense caused by waiting for it to break.
If you have any questions, post a comment, and I’ll be happy to help with an answer.
Next month: Little Known Reasons to Change Engine Fluids.