Alfa Romeo 156: Water pump and cooling-system leaks leading to overheating

The engine-driven water pump on the 156 (petrol and JTD diesel) commonly begins to weep or leak from its seal, often from around 80,000-120,000 km, and radiators, plastic coolant unions and hoses go brittle with age. Owners report coolant loss, a rising temperature gauge and overheating risk. On belt-driven pumps the failure can also destroy the cam belt, so the pump is normally replaced at each belt change. Chronic overheating on these alloy engines can lead to head-gasket damage, so leaks should not be ignored.

• Coolant loss and low reservoir level
• Coolant puddle or dried residue under the front of the engine
• Temperature gauge rising or overheating in traffic
• Sweet coolant smell or visible weeping from the water pump
• Heater blowing cold or steam from under the bonnet

1. 1

   With the engine cold check the coolant level and look for crusty residue or weeping around the water pump, radiator seams, plastic unions and hose joints.

2. 2

   Warm the car fully and watch the temperature gauge stays steady in traffic; feel that both radiator hoses get hot (thermostat) and check the cooling fan cuts in.

3. 3

   Ask when the water pump and cam belt were last done together, and look for mayonnaise on the oil cap or cross-contamination that would hint at earlier overheating or head-gasket damage.

Parts involved: Water pump.

$400 to $1,300 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Has the water pump been replaced, and was it done with the cam belt?”
• “Does the temperature gauge stay steady in traffic, or has it ever overheated?”
• “Is it losing any coolant or leaving drips where it's parked?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.