The water pump is one of the most important components of a car engine. This is the element that allows the coolant to flow inside the circuit, preventing the engine from overheating. A leak in the cooling system or its malfunction can cause serious engine damage. The duty of every motorist is to check for any problems and make any necessary repairs. If you notice fluid spots under the vehicle or if the engine temperature gauge is too high, it may be time to replace the water pump.
Steps
Step 1. Leave the vehicle to rest overnight in the garage and make sure the floor is perfectly clean
If you can't park it on a clean concrete surface, place a piece of light-colored cardboard under the vehicle in the engine compartment.
Step 2. The next morning, check the status of the carton
If it looks wet, it means there is a leak. Most likely it is the seal or the water pump. If you notice the presence of green liquid, it is antifreeze, which indicates a leak somewhere in the cooling system.
Step 3. Check the water pump pulley
This is the circular component of the water pump to which the drive belt is attached. Try to move the pulley back and forth; if it has excessive play, it may need to be replaced due to high bearing wear.
Step 4. Listen for the noise coming from the engine compartment
Open the hood of the car and start the engine. A hollow, grinding noise is a clear sign of wear on the water pump ball bearings. It is a well audible and recognizable sound.
Step 5. Check for liquid leaks near the water pump and its seal
If you notice liquid droplets or steam escaping, there is a leak.
Step 6. Check to see if the dashboard light for the thermostat that controls the water temperature comes on
When the engine is not receiving enough coolant due to a malfunction or leak, the engine temperature rises causing the engine warning light to illuminate.
Step 7. Check if the coolant level indicator light is flashing
It could indicate that the coolant reservoir has a leak or that the water pump is not working properly. Alternatively it is possible that the leak is somewhere in the cooling system.
Step 8. Check the operation of the car air conditioner
If the air conditioner does not work properly, the cause may be due to a malfunction of the water pump.
Advice
- If you find a puddle of liquid under the car on a very hot day it doesn't necessarily mean there is a problem with the water pump or cooling system. Condensation forms when the air conditioning is running and can drip from the underside of the engine compartment, which is perfectly normal.
- Look for a small hole near the water pump pulley. This is a drain hole from which coolant leaks in case the pump malfunctions or breaks.
- In some vehicles the water pump is not visible because it is hidden by the protective cover of the belt or the timing chain. You should still be able to notice any coolant leaks near the area where the pump is located. Removing the timing belt protective cover is a very demanding job.
- In some cases it is possible that there is no visible fluid leak or suspicious noise, and that all other components are functioning correctly (e.g. fans, belts, hoses, thermostat, radiator, internal heater, plugs, etc.). Only in the event of overheating may you notice steam escaping from the radiator cap or coolant expansion tank, but in most cases, this is completely normal as these components are specially designed to act as a relief valve when the pressure in the cooling system becomes excessive. In this way, the integrity of all other parts is preserved.
- The blades of the internal fan that pushes the coolant of some water pumps are made of plastic. Sometimes the coolant can become corrosive, when the additives of which it is composed lose their effectiveness (it is assumed that the liquid of the cooling system of a car must be changed regularly every 3-7 years of use, precisely to avoid damage to the engine when the additives of which it is composed lose their effectiveness). The blades of the internal fan of the water pump, being made of plastic, can be dissolved and no longer able to move the coolant inside the circuit, consequently causing the engine to overheat. To check for this problem, perform the following test: Start the engine from cold with the radiator cap removed. You should be able to see the coolant moving inside the radiator. If not, it is very likely that the internal fan of the water pump has worn out completely or almost.
Warnings
- After using the car, if the coolant level is low, wait until the engine has cooled down before refilling. When the engine is still very hot, adding water or cold coolant can cause metal parts to crack due to the extreme temperature range it would be subjected to. In this case, the repair costs would rise enormously.
- Do not use 100% pure coolant to fill your car's cooling system as it will cause the engine to overheat. Follow the instructions in the vehicle maintenance booklet. Normally car manufacturers recommend using a mixture of 50% coolant. In some cases, the coolant percentage can be 70%. If you don't live in an area with a very cold climate, you can dilute the coolant using pure water.
