You probably need a new thermostat, when they fail they usually fail open, so the coolant circulates around the radiator and engine when its cold instead of just the engine, so the system will not reach it's optimum temperature which is around 80deg C. Changing the thermostat should solve the problem. The thermostat is under a housing, follow the top hose (large) from the radiator back to the cylinder head and you should find the thermostat housing. Make sure the engine is cold before you undo any screws, drain the system first before attempting any repair. If there isnt a drain screw on the bottom of the radiator remove the bottom hose and drain into a clean container. If the coolant is older than 2 years your better off changing it for manufacturers recommended, protection down to at least -25deg C. Fill the system and leave off the expansion chamber cap, undo any bleed screws on the top hose and allow the engine to warm up at idle speed, once coolant is seen flowing from the bleed screw seal it. Do not over fill the system. Turn off the engine when the temperature gauge is about mid way and allow the system to settle, top up if necessary.
Steve, February 2010
