How to fix a car’s water pump?

  Gasoline engines in cars use a mixture of antifreeze and water that is distributed through a radiator by a water pump to lower the temperature of the engine’s operation. The water pump can corrode or wear out and needs to be replaced when it fails. The bearings of the water pump are designed to […]


Gasoline engines in cars use a mixture of antifreeze and water that is distributed through a radiator by a water pump to lower the temperature of the engine’s operation. The water pump can corrode or wear out and needs to be replaced when it fails. The bearings of the water pump are designed to generate a leak when they fail and cannot be easily repaired. However, an average home mechanic can replace a water pump in most cars in almost an hour.

Remember that we can help you keep your car in perfect conditions here at JB Prestige automotive service you will find a team of qualified professionals for maintenance.

Replacing an automobile water pump

  1. Drain the system antifreeze by loosening the radiator drain plug or decoupling the lower coolant hose. Remove the radiator cap to release the negative pressure and allow the antifreeze fluid to drain until the system is empty.
  2. Remove the fan belts or serpentine belt that operates the water pump by pressing firmly on the tension pulley and then pulling out the belt or loosening the accessory that gives tension to the pump belt.
  3. Unscrew the water pump pulley by turning the heads counter-clockwise. Normally, the pump is held with two to four bolts in the motor, but the pulley is too large for you to reach the pump bolts. In these cases, you must disassemble the pulley to allow access to them. The water pump pulley is a design divided in half and can be set aside once it is disconnected.
  4. Unscrew and remove the old water pump by turning the bolts counter-clockwise. The pump is pulled straight out, and it can splash trapped antifreeze when you’re taking it out. There is a gasket on the inside edge of the pump, and there must be a new one included with the new pump. Clean the area around the water channel (where the pump has been mounted) and scrape any material from the old gasket.
  5. Place the new gasket and any adhesive that is included in the new water pump. If the edge of the pump mouth has a certain shape, then the gasket can only be inserted in a certain way. Many pumps simply have a circular opening. Putting this gasket correctly is fundamental for the life of the new pump.
  6. Install the new pump by bolting it to the motor and then connecting the old pulley. Replace the belt and apply tension in the same way that you released the tension of the pulley or tighten the fitting that applies pressure to the pump.
  7. Squeeze the drain plug on the radiator and reconnect all disconnected hoses.
  8. Refill the system by filling the radiator with antifreeze, then turn on the vehicle and continue pouring the coolant until it is no longer needed. Cover the radiator and fill the tank to the proper level.


Use a mixture of 60% antifreeze and 40% water during the first months after changing the water pump. The raw metal needs the additional protection of the chemicals in the antifreeze.

How to know if you should replace your car’s water pump

The water pump is one of the most important parts of your car. It is the piece that pumps water and antifreeze continuously to the engine of your vehicle so that it does not overheat. A leak or defective bearings can cause great damage to the engine. As the owner of a car, you should be aware of faults that require repairs or replacement. Water or antifreeze pools under your vehicle or high temperature readings may be signs that your water pump should be replaced.


  1. Leave your car parked at night on a clean concrete floor. If it is not possible to find a clean space, place a piece of clear cardboard directly under the engine.
  2. Examine the cardboard the next morning. If it seems to be wet, you have a leak somewhere, probably at the water pump or at the board. If you notice a green liquid in the cardboard, it is the antifreeze. This means that you definitely have a leak of antifreeze somewhere.
  3. Check the water pump pulley. Locate the round part of your water pump that is surrounded by the band. Try pushing the pulley back and forth. If it seems to be loose, it may be time to replace it because the bearing is no longer useful.
  4. Listen to your car. Start the engine with the hood open. If you hear a serious screech, it can be an indicator that your bearing is no longer useful. Normally it is very clear when it is no longer useful.
  5. Look for leaks around the water pump and gaskets. If you see water droplets or a small stream, there is a leak.
  6. See if the thermostat’s warning light comes on. If your car is not getting enough antifreeze due to a leak or a faulty water pump, the engine temperature will increase, turning on the warning light.
  7. See if the antifreeze level light is shining. This may be an indicator that the antifreeze reservoir is leaking or that the water pump is not working properly. Another alternative is that there is a leak in the cooling system.
  8. Pay attention to the air conditioning of your car. If the air conditioner is not working properly, the water pump is not doing its job well.

Some water pumps have fan blades made of plastic, which move the coolant, some being corrosive once the additives wear out (you’re supposed to change the coolant every 3 to 7 years to prevent the engine from getting damaged once that the additives wear out). The fan blades can dissolve, leaving the coolant circulating causing the car to overheat. To test this, perform a cold start with the radiator uncovered. You should see that the liquid moves around him. If it does not, there is a good chance that the inner blades of the water drool have corroded and only a small amount remains.

Here at JB Prestige Euro Automotive Service we take pride in providing the best services for European cars in our area.