Also known as a timing belt, if you have a traditional internal combustion engine your cambelt plays a vital role in your engine’s operation. In a nutshell, it makes sure that all the crucial components are working in sync with each other. If it fails, the damage can be severe and expensive to fix. EV owners don't have to worry about cambelts. but keep reading as you may learn something new about how ICE cars work.
Weighing up the cost versus the value of your motor, you may even decide to scrap your car. That’s where we can help, here at EMR Vehicle Recycling. For more than 70 years, we’ve been helping our customers get the very best prices for their end-of-life vehicles – so you don’t walk away empty handed.
But we’re getting ahead of ourselves. Instead, let’s get you up to speed on the symptoms of cambelt failure so that you can - hopefully - prevent the risk of it happening.
What a cambelt does in your engine
The cambelt is a reinforced rubber belt with teeth that keeps your engine’s camshaft and crankshaft moving in perfect synchronisation, so that the engine’s valves open and close at the right times during the intake and exhaust strokes. If the timing is correct, fuel enters the cylinders, combustion happens efficiently and exhaust gases leave without issues.
In most modern engines, the cambelt is hidden under protective covers, which means you can’t easily inspect it. The belt’s teeth are designed to grip gears securely, but over time the material can weaken from heat, wear and exposure to contaminants. If the belt slips or breaks, the valves and pistons can collide, often causing severe internal engine damage. Because of this, manufacturers specify replacement intervals for cambelts based on mileage or time, whichever comes first. Vehicle owners should check the handbook that came with the car for details.
4 common causes of cambelt damage
A cambelt can deteriorate for several reasons. Here are the most common:
- Age-related wear and tear
- Oil or coolant contamination
- Incorrect belt tension
- Faulty or worn pulleys and tensioners
Age-related wear and tear happens naturally over time. Even if your mileage is low, the rubber material in the cambelt can become brittle and crack. That’s why it’s important to keep replacing it at the manufacturer’s recommended interval, even if the car hasn’t been driven much.
Oil or coolant contamination is another potential cause. If there’s a leak from a gasket or seal, the fluid can seep onto the belt, weakening the rubber and causing it to slip or snap.
Incorrect belt tension can occur if the belt has been fitted too loosely or too tightly during servicing. Too loose and it may slip on the gears, too tight and it can put excessive strain on the belt and associated components.
Faulty pulleys or tensioners can also cause premature cambelt wear. These parts help guide and maintain the correct tension on the belt, so if they’re worn, misaligned or damaged, they can cause uneven wear patterns and eventual belt failure.
5 signs your cambelt may be failing
While cambelt failure can sometimes happen suddenly, there are warning signs to look out for:
- Unusual ticking or clicking noises from the engine
- Difficulty starting the engine
- Engine misfires or rough running
- Visible cracks or wear on the belt
- Oil or fluid leaks near the cambelt area
Unusual ticking or clicking noises from the engine often come from the cambelt area if the belt is starting to loosen or if the teeth are slipping on the gears. This sound can also be caused by the belt wearing unevenly, which can happen when a pulley or tensioner is no longer working as it should. If this is left unchecked, the slippage can worsen until the belt jumps teeth or snaps entirely, causing significant internal damage.
Difficulty starting the engine can happen when the cambelt has stretched or slipped enough to alter the engine’s timing. The spark plugs may fire at the wrong point in the cycle, making ignition harder. In some cases, the engine might crank for longer than normal or fail to start altogether. This problem can develop gradually, so it’s worth investigating as soon as you notice a change in how the engine starts.
Engine misfires or rough running are signs that the valve timing is no longer in sync with the crankshaft. A stretched or damaged cambelt can cause the intake and exhaust valves to open and close at the wrong moments, disrupting combustion. This may feel like a loss of power, hesitation during acceleration or a general lack of smoothness when driving. Continued use in this state can cause further stress to engine components.
Visible cracks or wear on the belt are clear physical warnings that it needs replacement. The rubber can dry out, split or develop frayed edges over time, especially in older belts. Missing teeth on the belt’s surface are an even more serious sign, as they reduce the belt’s grip on the gears, increasing the chance of sudden failure. If you – or more likely, your mechanic – spot any of these issues, the belt needs to be replaced immediately.
Oil or fluid leaks near the cambelt area are a double threat. The leak itself may be caused by a failing gasket or seal and, if the fluid reaches the belt, it can soften the rubber, making it slippery and weak. This contamination accelerates wear and can cause the belt to degrade much faster than usual - meaning the leak and the belt both need to be addressed at the same time.
What are the repair and replacement options for a failed cambelt?
If a cambelt has failed, the repair process depends on the extent of the damage. In non-interference engines, a qualified mechanic may be able to replace the belt and any associated parts like tensioners and pulleys without further work. However, in interference engines, a snapped belt often leads to bent valves, damaged pistons or even cracked cylinder heads, meaning an engine rebuild or replacement could be necessary.
When a mechanic replaces a cambelt, it’s standard practice for them to also replace the tensioners, pulleys and water pump - if it’s driven by the belt. This ensures the new belt runs smoothly and reduces the chance of future failure. The job requires precise alignment of the camshaft and crankshaft, so it’s carried out using specialist tools and technical procedures. In total the average cost of all this work is over £500 — which is quite an outlay for an older car.
Since it’s not something you can do alone, if your cambelt does break and you decide that it’s too expensive to get fixed, then you may consider scrapping your car. If so, EMR Vehicle Recycling is here to help. We’re dedicated to getting you the very best price for your old car. All you need to do is enter your car reg and postcode into the fields on our homepage, and you’ll have an instant online quote before you can say “scrap my car”. Ready to find out what yours is worth?
