We have created this guide to let you know the symptoms of a failing cooling system water pump, this will result in the engine creating noise, overheating or breaking the serpentine belt.
The water pump is designed with a weep hole to allow
coolant to leak from its housing
before it can reach the shaft bearing which will cause the shaft to lock up and
stop turning. If this shaft locks up it will cause the serpentine belt to break
which will cause a break down. It's typical for the pump shaft seal to leak while
the engine is running, and then stop leaking once the engine has been shut off.
When the coolant level inside the engine diminishes the engine will overheat which
can cause the block or cylinder heads to crack. It is difficult to replace the water
pump seal by itself which is why in most cases
the water pump must be replaced.
The water pump is designed with two shaft bearing which support the main shaft
of the pump. When these bearings go out they can cause a squeaking, ticking or grinding
noise because the shaft bearings are trying to lock up within the pump housing,
(sometimes a failing water pump will be silent). This bearing failure is due to
corrosion or the pressure being applied to the pulley by the serpentine belt or
the timing belt or chain. If the water (coolant) pump is not replaced it can cause
the pump to lock up which will derail or break the serpentine belt. Below is a water
pump being driven by the serpentine
belt and the tension being applied by the belt tensioner. To check the water
pump shaft bearings remove the belt
and grasp the pulley or fan and move it side to side, there should be little to
no play within the shaft bearings and the housing. An additional method to check
the bearings is to look straight down at the pulley and see the alignment of the
pulley with the other pulleys of the engine. If the water pump pulley is noticeably
offset then you know the bearings are bad.
The operation of the water pump is to circulate coolant throughout the radiator
and cooling system, if the impeller of the pump has an issue this circulation stops
and the engine will overheat.
To check for this condition lower the coolant level a few inches so you can see
the radiator cooling tubes, with the radiator cap off warm the engine, when the
engine reaches operating temperature you should be able to see coolant flowing from
the tubes if not this could be the failure. In the image below you can see the impeller
has dislodged itself from the main shaft.
Our certified technicians are ready to answer car repair questions for free. We hope you saved money and learned from this guide and video, we are creating a full set of car repair guides. Please subscribe to our 2CarPros YouTube channel and check back often for new videos which are uploaded regularly.