It is not unusual to hear about replacing timing belts in car engines, and there are specific service periods in which replacements are recommended so that you don’t suffer engine damage from a broken timing belt. Some cars do not have a timing belt, though. Some Volkswagens, for example, have a timing chain instead. So what then is the distinction between timing belts and timing chains?
A timing belt is a high-quality rubber belt with teeth. It is located outside the engine and has a cover that protects it from damage. This is the standard engine setup for most cars. The rubber material allows the belt to fasten tightly and smoothly to both the engine and the transmission. A harder material would not have as much cover area, giving it less traction or “grab.” The flexibility of rubber also allows for the tightest fit and least amount of slack, which gives the least amount of variation between the two turning points in the engine and transmission. For a belt connecting the timing of two systems, this lack of slack is critical to keeping things running in unison.
The downside of flexible rubber is that its elasticity eventually wears out, stretching it to the point that it loses traction and can slip. As the elasticity fades away, it becomes brittle, which leads to cracks and breaks. Once the rubber reaches this point, there is no fix possible. You have to replace your belt. Fortunately, rubber is not a terribly expensive material and the replacement belt typically only costs between $25 and $50. You will spend the bulk of your money on the labor that it takes to replace the part. If you put it off and wait until the belt breaks, you will end up paying much more to repair the engine damage it will likely cause.
A timing chain operates like a bicycle chain that connects from the inside of your engine to the transmission, the way your foot pedals connect to the wheel gears on a bicycle. Like the timing belt, the goal is to keep the engine and transmission running in unison. Unlike the timing belt though, a timing chain is made of metal links instead of rubber. Whereas your timing belt will wear out and require replacement anywhere between 40,000 and 100,000 miles, a timing chain does not wear out. It will only need a replacement if something goes wrong with it.
What could go wrong with it? To begin with, it requires oil from the engine to keep it lubricated. If it loses lubrication causes the timing chain to gather too much friction and start to wear out quickly. Lack of oil is common in vehicles with high mileage.
Rubber has a natural elasticity that keeps it tightly connected to the engine. Metal does not. To compensate for this lack of flexibility, timing chains have an apparatus called a chain tensioner that keeps them tight and prevents them from vibrating. This tensioner can be a spring-loaded part, or they can be operated by oil pressure in the engine. These timing chain tensioners have chain guides and chain silencers that help hold the chain in place, but these parts all wear out over time and need to be replaced.
Why is vibration a bad thing? Vibration indicates a loss of energy that reduces speed and control, and more importantly, throws the timing off inconsistently. It also creates friction and produces heat. The more your timing chain vibrates, the slower and hotter your engine will get. That is a counterproductive way to drive.
Signs of Trouble
If your car is making rattling, whirring, whining, or buzzing noises, your timing chain may be coming loose. You may notice a lack of power in the engine and trouble starting your Volkswagen. These noises are all signs that you should replace your timing chain. When your timing chain gets too worn, it is usually replaced with a new kit that contains a new tensioner and chain guide, as well as a few other parts of the timing chain apparatus. Some vehicles have more than one chain. In these cases, professional technicians often recommend replacing all of them. These kits usually cost between $150-$250, but with the labor included, it could cost you up to $1500.
You can find information for installing a new timing chain in your service manual. However, be warned that older pushrod engines are much easier to replace the timing chain in than newer models with front-wheel drive. Their transversely-mounted engines do not give you much space to work. Prevention is the best way to deal with timing chains. Keep your engine well-oiled, and your timing chain can last up to 300,000 miles.
Timing Chain Help
If you suspect your timing chain may be going bad, come see our expert European Auto technicians at A&M Auto Service, convenient to Pineville, Charlotte, and Greensboro, NC. Our family-owned business will give you peace of mind while we handle your car maintenance. Set up an appointment with A&M Auto Service today.