Cooling system troubleshooting (Peugeot 305)

The engine gets very hot

(check if the temperature gauge is giving correct readings)

• Low coolant level (for example, due to a leak)
• The drive belt is broken or slipping
• Low engine oil level or wrong grade of oil
• Thermostat is faulty
• The fan clutch is not working properly
• The water pump is faulty
• Internal or external clogging of the radiator core
• The valve in the radiator cap is faulty
• The new engine hasn't broken in yet (reduce speed)
• The brakes are sticking (see chapter 8)
• The ignition timing is too late or the automatic ignition timing correction does not work (see chapter 4)
• Too lean mixture (see chapter 3)
• The cylinder head gasket is blown
• The cylinder head or cylinder liner(s) is warped or cracked

The source is located on the website (PeugeotBook)

The engine warms up poorly

(check if the temperature gauge is giving correct readings)

• Thermostat is faulty
• The fan clutch is not working properly

External coolant leak

• Too much coolant in the system (thermal expansion leak
• The hoses are damaged or loose
• The water pump or thermostat gasket is leaking
• The valve in the radiator cap is faulty
• Water pump seals are leaking
• The radiator core is damaged
• The heater core is damaged

Internal coolant leak

• The cylinder head gasket is blown (coolant enters the exhaust gases or the combustible mixture in the combustion chambers)
• The cylinder head or cylinder liner(s) is warped or cracked
• Cracks in the intake manifold.