Merely checking the output voltage of the batteries is not indicative of their ability to deliver adequate starting power. As batteries age, their internal resistance to current
Cooling system service
Check the coolant level during shutdown periods at the interval specified in FIGURE 1. Remove the radiator cap after allowing the engine to cool and, if necessary,add coolant until the level is about 3/4-inch below the radiator cap lower sealing surface. Heavy duty diesel engines require a balanced coolant mixture of water,antifreeze and coolant additives. Use a coolant solution as recommended by the engine manufacturer.
Inspect the exterior of the radiator for obstructions and remove all dirt or foreign material with a soft brush or cloth. Use care to avoid damaging the fins. If available,use low pressure compressed air or a stream of water in the opposite direction of normal air flow to clean the radiator. Check the operation of the coolant heater by verifying that hot coolant is being discharged from the outlet hose.