How can I tell if the water pump in my car is faulty?

To prevent the car's internal combustion engine from overheating, constant cooling is essential. The water pump provides a constant flow through the cooling system and keeps the engine temperature low. However, the water pump can become defective, especially after high mileage. In our guide, we explain the symptoms of a faulty coolant pump and why it fails. You'll also find valuable tips on how to replace your water pump.

Why are water pumps important?

The pump circulates water

When the engine is running, the water pump circulates coolant. It moves coolant heated by the engine to the radiator and coolant cooled by the radiator back to the engine. In this way, the coolant circulates reliably through the radiator at the front of the vehicle. The temperature of the coolant is significantly reduced. The cooled coolant is then returned to the engine. If the cooling circuit is interrupted, the engine will gradually overheat, causing permanent and extremely costly damage.

Typical Symptoms of a Faulty Water Pump

When the water pump is defective, typical symptoms often occur.

Low coolant level

Water pump leaks are common, especially in older vehicles. In this case, the water pump failure is announced very early by a coolant leak, which often evaporates immediately due to high temperatures. A drop in the coolant level in the expansion tank often indicates a faulty water pump.

Water under the car

If the water pump is leaking badly, symptoms such as dripping coolant may occur. A small or large loss of coolant is always a sign of a cooling system problem. Coolant usually forms a puddle under the vehicle. However, this symptom can also indicate damage to the radiator, cylinder head or piping system.

Distinct noises.

If the water pump has suffered mechanical damage, it will often make a noise. Knocks, creaks, and squeaks can all be signs of a damaged water pump. However, these sounds are usually only audible when the engine is running with the hood open.

Significant engine overheating.

If the damage is such that the cooling system fails, the engine will overheat very quickly. Pay close attention to the engine temperature gauge on the dashboard. This is the most common warning. It indicates that your engine or radiator is overheating.

Heater failure.

A faulty heater can also indicate a problem with the cooling system. The vehicle should be stopped and repaired as soon as possible.

Possible causes of a water pump fault

There are several possible causes of water pump failure. Especially with high mileage, gradual wear and tear is often responsible for a faulty water pump.

Water loss due to worn seals

In addition to wear and tear, aging materials are often the cause of water pump failure. Constant high temperatures can cause water pump seals to become brittle and porous. As a result, more coolant escapes. The coolant can also be damaged by contamination or improper additives.

Other problems

• Water pump wear due to high mileage
• Broken internal propeller
• Aging of seal materials
• Foreign matter in the coolant
• Coolant additives not approved by the manufacturer

How to check an automotive water pump

• Step 1: Check the temperature gauge
• Step 2: Listen for noise
• Step 3: Turn on the heater
• Step 4: Check the pulley
• Step 5: Look for coolant leaks