A puddle of coolant and a climbing temperature gauge could mean a split hose or a failing water pump. The repairs differ a lot in cost, so it is worth understanding the clues.
Signs pointing to a hose
- Visible cracks, bulges or a soft section on the hose.
- Coolant residue at a hose joint or clamp.
- A sudden large leak or a burst under pressure.
- The leak is at the top or side of the engine, following the hose route.
Signs pointing to the water pump
- Coolant dripping from the front of the engine, near the drive belts.
- Dried coolant streaks below the pump's weep hole.
- A whining or grinding noise from the front of the engine that changes with revs.
- Play or wobble in the pump pulley.
How a workshop confirms it
A cooling-system pressure test pressurises the cold system to normal operating pressure so leaks show up without the engine running. Some technicians also add UV dye to the coolant. If the pump is driven by the timing belt, it is common practice to replace the belt and pump together.
Do not keep topping up
Topping up with water to get home is acceptable in an emergency, but running a leaking system for weeks risks overheating, head-gasket damage and diluted coolant that no longer protects against corrosion. See why engines overheat in Qatar.