Finding out that your timing belt (or cambelt) needs to be replaced tends to fill drivers with dread; cambelt replacement is costly and doesn’t seem to make any difference to a vehicle’s performance. However, failing to replace your cambelt can result in even more costly, and potentially dangerous, damage to your vehicle. So, what is a cambelt, and why is it worth making sure yours is safe?
What is a Cambelt?
Cambelts connect the moving parts within a vehicles engine: the crankshaft, the camshaft and the valves. Before the 1970s, vehicle manufacturers used chains to transmit motion between the engine crank and the camshafts, making sure that the complex parts of a vehicle’s engine are synchronised. Nowadays, rubber cambelts are used because they are lighter and quieter; however, they also wear out and stretch, unlike the old-style chains. As a result, some car manufacturers are now reverting to using chains, which are designed to last throughout the engine’s life.
When to Change a Cambelt
Based on average use, a vehicle’s engine will make over 35 million revolutions each year. A range of factors cause inevitable wear and tear on your cambelt; dust, moisture, vibrations from the engine and heat cause the rubber to stretch or weaken. When this happens, the cambelt can slip or fail.
Each vehicle manufacturer will have its own recommendations for cambelt replacement, usually between 4 years or 40,000 miles and 5 years, or 60,000 miles. Some vehicle owners choose to err on the side of caution and replace their cambelt before the recommended time or mileage. If you experience any of the following, check with your garage; your cambelt may be damaged and may need to be replaced immediately:
- Your cambelt is under most strain when the engine makes sudden changes in speed, for example, when you are moving off or changing gear. If your cambelt makes a noise, such as grinding, hissing or rattling, contact a local garage. A squealing noise is a good indication that your cambelt is loose, which could indicate that it needs replacing as it has stretched. If you have recently had a new cambelt and it squeals, you need to get it tension adjusted and checked for unusual wear or flaws.
- If your cambelt is damaged or has slipped, it is possible that your vehicle won’t start at all. This can be easily diagnosed by a garage, who will check to see if the camshaft turns while the crankshaft is turned. If the camshaft doesn’t turn, the cambelt is broken.
If your cambelt snaps or slips out of place while you are driving, it can cause a significant amount of damage to your vehicle. If you are in any doubt about the age or condition of your cambelt, consult a reliable local garage who can do some simple, visual checks to make sure that your cambelt is in good condition.