CAR CARE - TIPS AND TRICKS

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Car Cooling System Fault Finding Tips

Overheating
Insufficient coolant in system - Thermostat faulty - Radiator blocked or grille restricted - Electrical cooling fan faulty - Temperature gauge sender unit faulty - Air locked cooling system - Pressure cap faulty.

Overcooling
Faulty thermostat - Temperature gauge sender unit faulty.

Coolant leakage
Damaged hoses or hose clips - Radiator core leaking - Pressure cap faulty - Water pump seals leaking - Boiling due to overheating - Core plug leaking - Cylinder head gasket leak - Cracked cylinder head or cylinder block.

Corrosion
Infrequent draining and flushing - Incorrect anti-freeze mixture or wrong type.

Simple thermostat test
Lower the thermostat into a pan of boiling water, if the thermostat fails to open fully within a minute renew it. The thermostat should close as the water cools, again, if not renew it.

Draining and Flushing the Car Cooling System
Draining the system: When the engine is cold - remove cap from radiator or expansion tank (attempting this when the engine is hot can result in serious scalding) - Disconnect the bottom hose from the radiator and drain into a suitable container.

Flush the radiator by inserting a garden hose into the top and run the water until clear. Reverse flush the system by removing the thermostat and inserting a garden hose until the water flows clear from the bottom hose. In severe cases the radiator should be removed and flushed in the reverse direction of normal flow.

The heater may be flushed by disconnecting the hoses on the bulkhead and connecting the garden hose to one side and flush until the water runs clear out of the other. This can be repeated in the other direction. (The heater control slides may have to be in the full on position).

Refilling
Reconnect all hoses, add anti-freeze to system using recommended ratio and grade for your vehicle. Fill system slowly with water to cold level mark on expansion tank if fitted, or an inch below radiator cap. Replace the filler cap/s, run engine until normal operating temperature is reached while keeping a careful lookout for leaks. Turn off engine and leave to cool for at least 2 hours, then check coolant level, top up as necessary.

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