Water pump leak diagnostics

March 31st, 2025
Water pump leak diagnostics Leaky water pump caused by liquid sealant (pump was already leaking during the warm-up phase)

Water pump leak diagnostics

March 31st, 2025
Water pump leak diagnostics Leaky water pump caused by calciferous water (hard water)

Water pump leak diagnostics

March 31st, 2025
Water pump leak diagnostics Leaky water pump caused by rust in the cooling liquid (lack of corrosion protection in the coolant)

Water pump leak diagnostics

March 31st, 2025
Water pump leak diagnostics Excess use of liquid sealants (in this case, silicone)
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What can happen if too little coolant is in the cooling circuit (also known as the engine cooling system)? Is there a risk of overheating or even an engine fault if the coolant is dirty? What do squeaking noises and other indications of faults on the water pump in the vehicle mean? All of these points described can result in defective gaskets and premature failure of the water pump. You can find further causes of leaks, or wear, in this article from Pierburg.


The sliding ring seal is normally damaged by dry running of the water pump (lack of coolant) and due to polluted coolant. Both issues lead to abrasive seal wear, and premature failure of the water pump.

Causes of leakage:
  • Operation of the water pump without cooling liquid.
  • Contaminated coolant (rust, corrosion products, lime, liquid sealant, oil, sand, etc.).
  • Turning the new water pump by hand (damaging the sliding ring seal). The sliding ring seal, which is still dry, starts making a squeaking noise. The longer the pump shaft is turned back and forth, the louder the squeaking becomes.
  • Use of incorrect, corrosive or unsuitable coolant.
  • Impacts on the pump shaft (sliding ring seal fracture due to vehicle accident or inexpert installation).
  • Pump bearing worn-out.
  • Use of radiator sealant additives in the coolant (sliding ring seals are stuck).
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