Mitsubishi Repair: L200 Warrior 2004 2.5 diesel manual, l200 warrior, coolant fluid

Question
I have had overheating problems.  Thermostat is fine water pump changed.  the AA man who recovered me said it wasnt the head gasket as he tested to see.  what other things could it be?

Answer
Barry,
This could be a failing radiator fan or an inefficient radiator.  If the radiator appears to have lots of bent fins and the fans are not turning on at the appropriate time, this can cause an overheating problem.  There's also the possibility the coolant fluid has very dirt and is no longer good at cooling the engine.  A coolant flush may be in order.  Also, an improper water/anti-freeze mixture or air bubbles in the coolant system can also cause this problem.
Good luck!