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When a car gets to where it’s supposed to go without making any strange noises or expelling visible smoke, most people don’t give much thought to what’s beneath the hood of their car.

But belts and hoses are critical to making the car and its components run efficiently, and can fail without much warning. It pays to understand what can cause them to fail and how often they should be replaced.

What do belts do?

Belts are used to run many of the accessories and systems in your car, such as the cooling system, water pump, alternator, and power steering pump. In newer cars, one serpentine belt runs all of these.  In older cars, there is a separate V-belt to run each individual component.

In most cars today, another kind of belt, called a timing belt, is a critical part of how the engine works. In some cases, a timing belt also runs other components such as the oil pump and water pump. Note, not all cars have a timing belt but might have a timing chain instead.

What do hoses do?

Hoses carry various fluids and gases throughout the vehicle. The radiator outlet hose carries coolant to the engine from the radiator. Once the coolant has circulated through the engine, the radiator inlet hose carries the coolant back to the radiator to cool off again.

How are belts and hoses damaged?

Coolant hoses can be damaged by the fluid that runs through them because of something called ECD.  ECD stands for Electrochemical Degradation. ECD happens because the hose, the coolant, and the engine form a kind of battery and the coolant can actually become conductive of electricity, which pits and damages the hose.  

Hoses are also damaged by heat, because it breaks down the rubber. Friction from rubbing on engine parts can also damage the hoses.  And the hoses naturally degrade as they age.

Belts can be broken down by heat, age, ozone, oil, and friction.

What happens if a belt breaks or a hose springs a leak?

The upside of having a serpentine belt that runs everything is that it’s efficient and easy to manage. The downside is that when it breaks, all of that stuff that turns out to be very important to the running of your car stops working.  

If the timing belt breaks, the engine will stop running. Depending on the engine design, when a timing belt breaks the engine may also be damaged.  

Even if a belt just loosens, it will slip and lose efficiency. All of those things that are run by it won’t run as well.

If a hose for the coolant system springs a leak, the heating/cooling system can fail and the engine can even overheat. A leak in a vacuum hose will cause the idle to be rough, the car will lack power on acceleration, and there will be a decrease in gas mileage.

Diagnosis of belt and hose problems

Check belts when the engine is turned off and cool. When checking belts, look for fraying, cracks or splits, or glazing on the sides of the belt.  You’ll need to twist the serpentine belt to see if there are separating layers, cracks, or missing pieces of the grooves on the underside.  

If you have a problem with your coolant hose, you’ll likely have coolant on the ground. In that case, take your car to your friendly mechanic for a cooling system pressure test to diagnose where the leak is coming from.

If you want to check for ECD, follow these steps:

• Makes sure that the engine is cool.
• **Never remove a radiator cap when the engine is hot.**
• **Remember than an electric cooling fan can come on at any time.**
• Squeeze the coolant hose close to the clamps. If it feels squishier than the rest of the hose, suspect ECD. The hose should feel firm but pliable.
• Look for cracks, glazing, bulges, and friction points.

A vacuum hose leak can be found by lifting the hood when the engine is running and listening for a hissing sound. Of course you need to be very careful when you’re dealing with a running engine. If you hear a hissing sound, tell your mechanic who will know how to find the leak.

How often should belts and hoses be replaced?

Belts and hoses should be replaced when they show signs of wear or when they reach a certain age or mileage. However, some newer belts are made of a composite material that doesn’t show any wear until they fail, so in that case it is very important to follow a replacement schedule.

• A serpentine belt should be replaced at four to five years or at 50,000 miles.  
• V-belts should be replaced at three to four years or every 35,000 to 40,000 miles.  
• A timing belt should be replaced according to manufacturer’s maintenance schedule.  Usually this is at about 60,000 miles, but check the vehicle’s schedule to be sure.
• Hoses should be replaced every four to five years or when one fails.

Pay attention to your belts and hoses!

When a belt or a hose deteriorates, it will affect your car’s performance. A small leak in a vacuum hose might have a minor effect, but if the serpentine or timing belts break, your car might not run and could even have a damaged engine. Talk with your mechanic about the condition of the belts and hoses under the hood of your vehicle and make sure they are well maintained.    

Pfefferle Tire and Automotive Service is a two generation, family owned and operated repair shop.  Our services include quick lube service, tires and auto repair, and routine maintenance.  What sets us apart from other shops?  Our technicians do not work on commission, so there is no need for them to oversell.  We like to say, "We advise and you decide!"  
 
Contact Pfefferle Tire and Auto Service to schedule your preventive maintenance appointment! (513) 829-1900 in Fairfield or (513) 894-0025 in Hamilton.