Insights
Cambelt Replacement: Why You Cannot Afford to Put It Off
The cambelt is one of the most important parts of your engine, and also one of the easiest to forget, because it is hidden away and gives no warning before it fails. Skipping or delaying a cambelt change is one of the most expensive gambles you can take with a car. Here is what it does and why it matters.
The cambelt, also called a timing belt, keeps the top end of your engine turning in perfect time with the bottom end. That timing is what lets the valves open and close exactly when they should as the pistons move. It is a toothed rubber belt, and like any rubber part it ages, hardens and eventually wears out, whether the car is driven hard or barely at all.
Here is the part that catches people out. On many engines, known as interference engines, the valves and pistons share the same space at different moments. If the cambelt snaps or jumps while the engine is running, that careful timing is lost, and the valves and pistons collide. The result is often bent valves and serious internal damage, which can cost more to repair than the car is worth. A cambelt is cheap insurance against a very expensive failure.
The key with cambelts is that they are replaced on a set interval, not when they show a problem, because they give no real warning before they go. The exact figure varies by engine, but it is commonly somewhere around 100,000 kilometres, and many manufacturers also set a time limit such as every five or so years, because the rubber degrades with age regardless of distance. Your handbook or a quick check with us will tell you the right interval for your engine.
There are a few things worth knowing when you have it done. It usually makes sense to replace the tensioner and idler pulleys at the same time, because they wear alongside the belt and it is far cheaper to do them together than to go back in later. On many engines the water pump is driven by the cambelt too, so replacing it during the same job is a smart, money saving move. Doing the lot at once means you are good for another full interval.
Be especially careful when buying a used car. Many people have no idea when, or if, the cambelt was last changed, and a missing or overdue cambelt is a real risk hiding behind an otherwise tidy car. If there is no record of it being done, it is far safer to assume it is due and budget for it than to find out the hard way on the motorway.
The simple message is that a cambelt is not a job to push out to save a bit now. Done on schedule it is a routine, planned cost. Left too long it can write off your engine. If you are not sure where your car stands, bring it in and we will check the history.