Why Is My Car Overheating?

One of the most important parts of your vehicle’s cooling system is the water pump. For more than a century, all water pumps have been pulley-driven, featuring a belt connected to the crankshaft. On older cars, the water pump has a belt of its own, while on newer cars, it’s driven by the same belt that powers the alternator. On the latest cars and trucks, however, electronic water pumps have replaced pulley-driven ones. These are more energy-efficient and help lower emissions. They’re also great for hybrid vehicles, which still require coolant flow when running on the battery.

There are a few ways that a water pump can stop working. A failed belt is the most common and the most obvious. A failed belt can’t spin the pump. That means coolant will no longer circulate, causing your car to overheat. A quick look under the hood will let you know whether the belt has failed. If it’s simply misaligned, you’ll hear a squealing noise.

Another common way is for the pump’s internal seals to fail. When this happens, you’ll usually see small amounts of coolant leaking from a small hole in the bottom of the pump. That opening is called a weep hole, and it’s there precisely to let you know when the pump seals have failed.

Finally, the vanes on the pump inside the engine can wear out. When this happens, the pump looks fine but is no longer move any coolant. The cause is usually corrosion issues due to not changing your coolant or using the wrong one.

After oil, the most important fluid in your engine is coolant, also known as antifreeze.

Coolant gets pumped through the engine block and cylinder head through special passages inside the metal. The fluid carries heat from the hottest points of your engine to the radiator to keep the engine from overheating. Coolant is used because air alone can’t dissipate enough heat.

Engine coolant is more than just water. It’s possible to run your engine on pure water, especially in an emergency, but not for long. Car coolants contain anti-corrosion chemicals designed to make sure your engine doesn’t rust from the inside. With pure water, you’ll start to see rust in just a few minutes. Coolant also doesn’t freeze at low temperatures, which is why it’s called antifreeze.

Automakers like to pick their own coolant formulations. Use the wrong one and your cooling system could fail or break down prematurely. NAPA Auto Parts carries a wide range of coolants that will keep your water pump, thermostat, and other parts working smoothly. Check with a NAPA Auto Parts specialist to make sure you get the right fluid for your vehicle.

Engine coolant can leak out through old and damaged cooling hoses. It can also leak from a bad water pump, radiator, or head gasket. Whatever the source, leaking coolant can leave you with overheating problems.

Your car runs best within a specific temperature range. If it’s too hot, it overheats; if it’s too cold, it loses efficiency. The thermostat helps keep it in the correct range.

The thermostat opens when the engine warms up to its operating temperature. When the engine is cool, the thermostat blocks the flow of coolant. When the engine warms up, the thermostat opens, allowing the coolant to pump through the radiator.

If your thermostat fails in the open position, you won’t get heat when it’s cold out. Your car may also idle poorly since it’s struggling with the cold. If the thermostat fails while closed, your engine can overheat in a hurry.

The mechanics of the radiator are simple. It transfers heat from the hot coolant that flows through it to the surrounding air. If you don’t change your coolant, your radiator can clog. It can also get damaged by rocks and other debris. These radiator issues can make your car overheat. In some cases, the problem can be fixed, but more often than not, the radiator has to be replaced. It’s a tough job, but you can trust your NAPA AUTOPRO service centre to do it right.

The last common cause of an overheating engine is an issue with the cooling fan. When you’re idling or travelling at low speeds, the breeze from driving isn’t enough to cool your vehicle’s engine.

Old cars have mechanical fans mounted to the water pump, either directly or through a clutch. If the clutch fails, the fan won’t spin, and your car can overheat.

Modern cars use electric fans. These don’t have a clutch, but they can still fail. The motor can seize, wiring can become damaged, or the temperature sensors can stop working. The first two problems must be confirmed through a visual or mechanical inspection, while the third should trigger the check engine light.