13 Belts and Hoses To Check On Your Car (Especially Before Winter) | Family Handyman

By Bob Lacivita

Published on Oct. 22, 2024

Belts and hoses protect your engine and keep it running and operating properly. Winter temperatures can cause them to unexpectedly fail.

With well over 50 years in the car repair industry and as a vehicle owner, I have seen firsthand how extreme winter (and summer!) temperatures wreak havoc with drive belts and hoses in our vehicles. A weak or worn hose splitting open or a drive belt shredding can quickly cause a side-of-the-road breakdown at the most inopportune time. Visually inspecting your car’s belts and hoses should be a regular part of your monthly maintenance schedule. However, winter’s frigid temperatures, combined with the added stress on our vehicle’s systems, can be especially hard on cars. That’s why it is essential to check belts and hoses before the weather turns harsh.

Ahead, master auto technicians share their expertise and practical tips to help prevent breakdowns and increase your driving safety and comfort.

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Cold weather causes rubber—and other components made from rubber composites and synthetics—to shrink and become brittle. This makes them more likely to crack or leak, especially for hoses exposed to constant freeze/thaw temperatures in the engine compartment. Check all hoses for surface cracking, dry rot, leaking or splitting at connection points or fittings, and squeeze to ensure they are not mushy or leaking.

Most car hoses are made from rubber or rubber composites that may be reinforced with polyester strands or metal wire. Other hoses can be made of plastic composites. Some hoses use traditional worn hose clamps, while others are secured with threaded metal fittings or spring retainers that rely on rubber or composite seals or O-rings to seal the connection. High-pressure hoses may use crimp-style metal hydraulic fittings, which are notorious for leaking. High-pressure hoses should be pliable, not soft, when squeezed.

Replace any hoses that feel soft, show signs of bulging or swelling, or have coolant or fluid seeping through. Inspect the areas around the hose clamp connections for any whitish or colored powder or crust buildup. This typically indicates a slow coolant leak but may also signal a deteriorating hose, hose clamp, or the part the hose connects to. For example, the thermostat housing may corrode due to old or degraded coolant. Over time, hose clamps can lose their elasticity from age, overtightening or improper installation.

Coolant hoses move coolant throughout the cooling system to help keep the engine at the correct operating temperature. A failed coolant hose can quickly cause the engine to overheat, steam to pour out from under the hood, and a slimy coolant to cover the engine compartment.

There are usually two radiator hoses: an upper and lower radiator hose. Typically, they are located at the top and bottom of the engine. They connect to the radiator inlet and outlet, carrying coolant circulated by the water pump between the engine and the radiator.

Tom Diamond, Master ASE and Mazda technician, recommends you “always replace both radiator hoses at the same time and flush the coolant system.” He also suggests checking the coolant recovery tank hoses.

Although most vehicles have two heater hoses, some cars can have four or more. Usually located at the rear of the engine, they connect to and transport hot coolant from the engine through the heater core, warming the passenger compartment and helping defog the windshield.

In a pinch, you may be able to repair, or disconnect the good heater hose from the heater core and connect it back to the engine—bypassing the heater core. This hopefully will get you home or to a repair shop. If one heater fails, replace them all.

These hoses carry fuel from the gas tank to the engine. Depending on your vehicle, they can be either low-pressure or high-pressure hoses. Fuel hoses and lines generally run from the fuel tank at the rear of your car, through the fuel filter, then into the fuel delivery system (injectors, carburetor, etc.). They may weave throughout the frame or undercarriage and can be tricky to locate or identify.

Check all fuel delivery system connections for leaks and ensure all hoses are secure. And word to the wise: never drive with a leaky fuel hose, because spilled gasoline can suddenly ignite, instantly ruining your day.

Brakes are your vehicle’s most important safety system. Because the front calipers turn with the wheels when steering, brake hoses are made from fiber-reinforced rubber, connecting the brake calipers to steel brake lines.

Brake hoses are susceptible to dry rot and cracking. Reinforced brake hoses should be difficult to squeeze. Replace immediately if you feel any weakness or swelling. Diamond recommends “replacing all brake hoses, even if only one shows signs of damage and flush the brake fluid to remove any grit from a deteriorating hose.” A leaking brake hose can prevent your car from stopping when the brake pedal is applied, often leading to a serious accident.

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Located under the hood and in and under the dashboard, vacuum hoses can range in diameter from 1/8 inch up to 3/4 inch and are used to deliver vacuum (negative) pressure from the intake manifold to the emission control and fuel control systems, the HVAC system, the brake booster and other systems that rely on vacuum to operate and function correctly.

Check these for damage or cracking, especially if your Check Engine Light (CEL) is on or your engine is running/idling rough. Bad vacuum hoses can prevent you from controlling which HVAC ducts you need hot air flow from—dangerous if you are unable to clear fog from the windshield. These hoses often become brittle and split right at the point where they connect to a device. Now is also a good time to check the wiper washer fluid hoses.

To help cool automatic transmission fluid (ATF) and engine oil, high-pressure hoses carry these fluids to coolers normally located in the radiator. These hoses usually run under the car, are constructed the same as brake hoses, only much larger and longer in size. High-pressure power steering (PS) hydraulic hoses transport power steering fluid between the power steering pump and the steering gear

An air intake hose directs outside air into the air filter housing, then the mass air flow sensor and finally into the intake manifold. A leak in this hose can result in all types of drivability issues, including stalling, poor fuel economy, increased exhaust pipe emissions or CEL to come on. Check for deteriorated rubber and that all device connections are properly installed, clean and secure.

Drive (V-belt) or serpentine belts are essential to keep your car running. They spin the alternator, water pump, air conditioning compressor, power steering pump, and, if your car has one, a supercharger or air pump.

Today, most serpentine belts are manufactured from a long-lasting ethylene propylene composite material (EPMD). Timing belts are usually molded from rubber or neoprene and have strong fibers or steel running the length of the belt (similar to a tire). Replace belts that are glazed, missing pieces/teeth, rounded over, have surface cracks, are covered in any fluid or are peeling or fraying.

V- and serpentine belts should be taut, with about a 1/4 inch to less than 1/2 inch deflection when pressed with your thumb along its longest run between pullies. ASE Master Technician Bernie Johnson stated, “The top of a V-belt should be even with the top of the pully (pullies) being driven.”

If your belts are squeaking or chirping, you need to check and inspect belt/pully alignment, pully grooves for rust or gunk, the idler pulley or if the spring-loaded automatic belt tensioner is fatigued.

Because most timing belts are usually hidden behind engine covers, they are often overlooked. If your car has one, check your owner’s manual on when you should replace the engine timing belt. The timing belt connects the camshaft and crankshaft gears. Johnson added, “If the timing belt in an interference engine snaps while driving, the pistons will slam into any open valves, causing a very expensive breakdown.”

That’s why it’s particularly important to inspect your timing belt before winter’s cold frosty weather arrives. If you can remove the front engine cover, check the timing belt for the same deflection (the longest run between gears) and wear issues as a serpentine belt.

No. According to Marc Hood, shop owner and ASE Master Technician. Although fuel, vacuum and transmission cooler hoses all look the same, “hoses are designed for specific applications.” Hood noted “fuel hoses will balloon and weaken” if used to replace leaking transmission cooler hoses, the same if using vacuum hose for a fuel hose.