The water pump or coolant pump is an integral part of a vehicle’s cooling system. Its job is to circulate coolant through the engine and to all the parts of the cooling system.
Without a functioning water pump, the vehicle will be unable to take the excess heat produced in the engine and transfer it to the radiator via the coolant. This means that the engine will start to accumulate too much heat and will lead to overheating which can cause major damage to the internal components.
The water pump is usually driven by the serpentine belt but may also be driven by the timing chain or belt inside the front cover of the engine. Because of this, the water pump can be affected by other failures like a seized alternator bearing or a broken serpentine belt.
Because coolant is inherently acidic, the water pumps will wear out over time – either by the gasket material sealing it – failing or the fins of the pump itself wearing away. This can also be accelerated by coolant that has degraded.
What Does It Cost to Repair a Water Pump?
Because water pumps can be built in many different ways and be located in different places in the engine, the costs can vary from vehicle to vehicle. Here are a few different examples of water pump replacement cost (or repair cost) to give you an idea of the range of prices (using an estimated US average shop rate of $80/hr):
1. A 2010 Toyota Corolla 2.4L is leaking coolant. The technician inspects it and finds the water pump bearing failed and is letting coolant leak out.
- Water pump – $48 approx.
- Coolant – $15 approx.
- Remove and replace – 2.3 hrs at $80/hr – $184
- Shop supplies – $10
- Cost of repair – $257
2. A 2014 Ford F-150 5.0L is whining from the front of the engine. The technician diagnoses the noise and determines that it is the water pump bearing.
- Water pump – $75 approx.
- Coolant – $15 approx.
- Removed and replace – 1.7 hrs at $80/hr – $136
- Diagnosis – 1.0 hr at $80/hr – $80
- Shop supplies – $10
- Cost of repair – $316
3. A 2006 Subaru Forester 2.5L is overheating. The technician performs cooling system tests on the engine and concludes that the water pump is not circulating properly. After removing the timing cover, the technician finds the water pump impeller is worn out.
- Water pump – $55 approx.
- Coolant – $15 approx.
- Removal and replacement – 3.0 hrs at $80/hr – $240
- Diagnosis – 2.0 hrs at $80/hr – $160
- Shop supplies – $10
- Cost of repair – $480
4. A 2001 Chrysler Sebring 2.7L has oil and coolant mixing, evidenced by a milky brown oil condition. The technician performs testing and diagnoses a water pump leaking inside the front cover.
- Water pump – $50 approx.
- Coolant – $15 approx.
- Removal and installation – 6.6 hrs at $80/hr – $528
- Diagnosis – 1.0 hr at $80/hr – $80
- Shop supplies – $10
- Cost of repair – $683
The average cost to replace a car’s water pump can be as low as $200 to $300 with an externally mounted water pump and as high as $600 to $800 if the timing cover must be removed in order to access the pump.
Note that these water pump prices can be higher if the pump failure causes an overheating issue as this can have many possible causes and takes longer to diagnose.
What are the Symptoms of a Failed Water Pump?
Water pumps can fail in three main ways – either by failing to circulate coolant, leaking or making noise.
When a water pump wears out, it may start to leak. This can be because the seal between the water pump and the block has worn down or the bearing on the water pump fins wears out and blows out the seal around it.
Because the water pump holds a lot of the coolant in the engine inside its housing, when they start to leak, it will be a major coolant leak and is most often not driveable when in this instance.
Since water pumps can be located inside the front cover of the engine and driven by the timing belt, they can also leak internally into the engine. This will cause coolant to mix with the engine oil which thins out the engine oil.
This can cause bearing wear inside the engine which can damage the engine. The symptoms of coolant mixing with the engine can be overheating as well as the oil appearing milky brown.
Water pump bearings can also start to make noise when they wear out which will sound like a squealing noise. This can sometimes be mistaken for a serpentine belt or pulley and should be diagnosed using either a stethoscope or an electrical noise diagnosis device.
The most damaging failure of a water pump is when the pump fins wear off of the pump drive and the pump is unable to circulate the coolant through the system. This leads to elevated engine temperatures and possibly overheating of the engine which, if left unchecked, can cause internal engine damage – including head gasket failure, damage to pistons and valves or cracks in the block or head.
These repairs can be very costly and thus, any overheating condition must be addressed immediately to prevent them.
How Can Water Pump Repairs be Avoided?
Water pumps are under heavy load whenever the engine is running. As such, they will eventually wear out with time – usually somewhere between about 150,000 and 250,000 miles.
One of the primary causes of water pump failure is a coolant that has degraded and as such, regular cooling system maintenance can help prolong their lifespan.
Coolant should be tested regularly for strength using a hydrometer and should read below -30 degrees Fahrenheit to be the correct mixture. If it fails the concentration test, the cooling system should be drained and refilled with the proper mixture of coolant.
If the coolant appears to have flakes or any rust coloring in the reservoir, the cooling system should be flushed with distilled water to clean out the buildups in the cooling system and then, filled with the proper mixture of coolant and water to achieve the correct strength.