Chronic Overheating (F and 2F Engines)
Symptoms
The temperature gauge climbs above normal under load, on hills, towing, or in slow traffic. In severe cases, the engine boils over and dumps coolant.
Cause
The F and 2F petrol engines produce substantial heat and rely on a mechanical fan and a single-core radiator that was marginal when new. Decades of scale buildup inside the block and radiator reduce coolant flow. The original fan clutch (if fitted) wears and stops engaging properly. Australian summer temperatures push the cooling system beyond its design limits, particularly in inland areas where ambient temperatures regularly exceed 40 degrees.
Fix
Start with the basics: flush the cooling system thoroughly (including the block, not just the radiator), replace the thermostat ($20-40), and check the fan belt tension.
If the radiator is original, have it tested for flow rate, a partially blocked radiator is the most common cause.
Re-coring ($300-600) or fitting an aluminium replacement ($400-800) solves the problem permanently.
An electric thermo fan ($150-300) provides additional airflow at low speeds.
On the 2F, also check the water pump for bearing play and weeping.
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