Belts And Hose Inspection
What Our ASE Certified Technicians Do
The following components are inspected. Their condition is recorded and compared to manufacturers' specs. Recommendations are made per the Motorist Assurance Program Uniform Inspection Guidelines. Exposure to heat, vibration, and contamination makes belts and hoses wear out faster than any other components in your car. That's why regular inspections are so important. Here are the belt and hose types in your car, along with their applications.
Visual Belt Inspection
- Checked for glazing, cracking, peeling and softening
- Checked for proper tensioning
- Checked for proper alignment of drive pulleys
- Condition of each belt is recorded
Accessory Drive Belts
While some accessories in your car are electrically powered by the charging system, others use the engine itself as their power source. The power for these accessories is delivered by a system of pulleys and belts. Examples of these accessories are:
- Water pump for engine cooling
- Power steering pump
- Air conditioning compressor
- Radiator cooling fan
Many late model cars use a single serpentine belt in place of individual belts to drive these accessories.
Hoses Visual Inspection
- Check for leaks
- Check for hardening, cracking, and softening
- Pressure test cooling system for leaks
- Condition of each hose is recorded
The hoses that convey your car's fluids are made of two rubber layers with a layer of fabric in between. Typical hoses include:
- Radiator and Heater Hoses - These hoses convey coolant to the engine and heater core.
- Fuel Hose - As the name implies, this hose transports gasoline from the tank to the engine.
- Power Steering Hose - It connects the power steering pump to the steering gear
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Think of the synthetic rubber timing belt, which is reinforced with fiber cords, as the drum major of car maintenance -- meaning it keeps everything in the engine in sync. When the engine is on, it's in constant, timed motion, thanks to the belt, the connection between the crankshaft and camshaft.
So why is this important? The crankshaft converts linear energy from the pistons, which move up and down, into rotational energy that eventually turns the wheels. The camshaft opens and closes the engine's valves to allow air and gas in and out of the engine. The timing belt links the two in harmony. Without it, the pistons and valves would collide.
Obviously, this is bad news for vehicle maintenance as this internal collision can cause destruction fair amount of engine damage. Therefore, it's important to stay ahead of your belt's lifespan -- traditionally replacing it every four years or 60,000 miles (96,561 kilometers) or, in newer vehicles, every 100,000 miles (160,934 kilometers). Be sure to check your vehicle's maintenance manual to see what your car or truck's manufacturer suggests.
So we've all accepted the timing belt's importance, but that doesn't mean you have to spend your days worrying that your belt will force you to pay a large maintenance bill. Instead, you can act as the band director and keep that timing belt in check by watching its wear and arming yourself with the knowledge to replace it. Read on to learn about the wear of your belt, typical tools needed in a repair and how to replace it.
Your car's timing belt is responsible for maintaining the precision that's crucial to your engine's functions. Essentially, it coordinates the rotations of the camshaft and crankshaft so the engine's valves and pistons move in sync. The expected lifespan of your timing belt is specific to your car and engine configuration, usually between 60,000 and 100,000 miles. (You can check your owner's manual or look online for your car's service schedule.)
The manufacturer's recommended intervals are a safe guideline; you probably won't need to replace your belt any earlier [source: Allen]. However, if you're approaching your service interval and have doubts about the belt's condition, you might as well get it replaced a little early. It'll be less expensive than waiting until after the belt breaks.
Why is it important to replace the timing belt on such a strict schedule? The belt is a synthetic rubber strap that contains fiber strands for strength. It has teeth to prevent slipping, which fit into the grooves on the end of the camshaft and crankshaft. It's a simple part for such an important function, and when it snaps, things get a lot more complicated. Unlike many car parts that gradually lose function as they wear out, a timing belt simply fails. Whether the belt breaks or a couple of teeth strip, the end result is the same. One minute, your car will be running perfectly; the next minute, it won't. You're in trouble if your car has an "interference engine," in which the valves are in the path of the pistons. If the camshaft or crankshaft moves independently in an interference engine, there will be at least one valve/piston collision. The fragile valves will bend, and you'll be faced with a costly repair.
It's easy to check the belt for signs of premature wear -- just locate it in the engine bay (usually under a plastic or metal shield that should be easy to remove) and check it for drying, fraying and discoloration.
The belt itself is inexpensive, probably costing less than $20 at an auto parts store. Your mechanic will probably charge several hundred dollars (or more) for a belt replacement service, though. Those hours spent dismantling and reassembling the engine bay add up quickly.
You can replace the timing belt yourself if you have access to the necessary equipment. In some cars, it's a straightforward procedure -- remove the engine covers and shrouds, line up the camshaft and crankshaft, slip off the old belt, and slip on the new one. Sometimes, though, it's a lot more complicated. For example, the timing belt might loop through a motor mount, in which case the mount would need to be removed to access the belt. You'd need an engine hoist or stand to safely remove and replace the mount [source: Juran].
Keep in mind that an error in this job, such as improperly turning the engine by hand or failing to coordinate the shafts, will cause the same damage as a snapped belt. Make sure you understand the procedure before getting started.
Need more help with the do-it-yourself approach? The next section will point you in the right direction.