SKF Timing Belt Kits - SKF.com

Failure analysis overview
Water pumps
Although modern coolant pumps are maintenance-free
for a number of years, they are not fault-free and some
problems do occur:
A water pump leak can be due to:
1. Damaged water pump seal due to incorrect
mounting.
2. The use of excessive or wrong sealant type with
gaskets or O-rings. This can lead to early leakage or
even incorrect mounting angle when tightened. This
leads to incorrect centering of the belt. Here, you
can see rubber residue on the idler and the coating
around/under the O-ring.
3. A badly corroded water pump, whose lifespan has
expired. This pump was not changed in time during
the timing system maintenance. A severe leakage of
coolant past the mechanical seal and out of the drain
vent, washed the grease from the bearing spindle
and this lead to the failure/breakdown.
4. Abrasive particles originating from metal corrosion/
erosion are carried around by the circulating coolant
and score the seal contact faces.
5. Worn spindle bearings allow shaft misalignment to
occur between the seal contact faces.
The water pump may be inefficient due to:
1. Metal corrosion/erosion gradually destroying the
form of the impeller vanes.
2. Excessive end float of the impeller spindle in its
bearing increasing the working clearance between
the impeller vanes and the pumping chamber.
3. Internal engine condition and component life is
highly dependant on good coolant, which prevents
the build-up of corrosive and/or calcareous
materials that are harmful to a water pumps’
components. A thorough flush through and complete
refill with approved coolant type for the engine is
recommended to ensure maximum life from a new
water pump.
1. Incorrect mounting
2. Excessive sealant
3. Life-span expired
15