- Check the fluid level in the reservoir tank. Marks are provided. Check when the engine is at operating temperature. Add a 50/50 mix to maintain performance.
- If it is necessary to add fluid, be sure to check level again soon.
- A coolant level that drops consistently is usually a sign of a small, hard-to-detect leak. In most cases, a loose or damaged hose is the cause of the coolant level drop. However, check the heater core. Check the coolant for droplets of engine oil and the engine oil for milky white contamination (emulsified oil). This would indicate an internal leak (blown head gasket or worse), which must be addressed.
At least once every two years, the engine cooling system should be inspected, flushed, and refilled with fresh coolant. If the coolant is left in the system too long, it loses its ability to prevent rust and corrosion. If the coolant has been diluted with too much water, it won't protect against freezing.
The radiator cap should be examined for signs of age or deterioration. Fan belts should be inspected and, if necessary, adjusted to the proper tension (please refer to "Belt Tension Adjustment" in this section).
Hose clamps should be tightened, and soft or cracked hoses replaced. Damp spots, or accumulations of rust or dye near hoses, the water pump or other areas, indicate possible leakage. This must be corrected before filling the system with fresh coolant.
Check the overflow tank cap for a worn or cracked gasket. If the cap doesn't seal properly, fluid will be lost and the engine will overheat. A worn cap should be replaced with a new one. The coolant should be free of rust and oil. If oil is found in the coolant, there may be a major mechanical problem.
While you are checking the coolant level, check the radiator cap for a worn or cracked gasket. If the cap doesn't seal properly, fluid will be lost in the form of steam and the engine will overheat. If necessary, replace the cap with a new one.
Periodically clean any debris (leaves, paper, insects, etc.) from the radiator fins. Pick the large pieces off by hand. The smaller pieces can be washed away with water pressure from a hose.
Carefully straighten any bent radiator fins with a pair of needle nose pliers. Be careful; the fins are very soft! Don't wiggle the fins back and forth too much. Straighten them once and try not to move them again.
Coolant found in late model trucks is normally a 50/50 mixture of ethylene glycol and water which can be used year round. Always use a good quality antifreeze with water pump lubricants, rust and other corrosion inhibitors, and acid neutralizers.
Also available is another type of antifreeze, propylene glycol, which is non-toxic.
Keep in mind that should you decide to use a propylene glycol antifreeze, you should follow the antifreeze manufacturer's instructions closely. Do NOT mix ethylene and propylene glycol together, as the benefits of the non-toxic propylene glycol would be lost. In the event you decide to change to propylene glycol, make sure to completely flush the cooling system of all ethylene glycol traces.
FLUSHING & CLEANING THE SYSTEM
The system should be completely drained and refilled at least every two years in order to remove accumulated rust, scale and other deposits.
- Remove the radiator and overflow tank caps.
- Place a drain pan of sufficient capacity under the radiator and open the petcock (drain).
- Drain the coolant from the engine block either by removing the drain plug or disconnecting the lower radiator hose.
- When the system is completely drained, close the petcock and fill the system with a radiator flush. Clean water may also be used, but is not as efficient.
- Idle the engine until the upper radiator hose gets hot. Be sure to put the heater on to circulate the water or cleaning fluid through the entire system.
- Allow the engine to cool and drain the system again.
- Repeat this process until the drained water is clear and free of scale.
- Flush the overflow tank with water and leave it empty.
Determine the capacity of the coolant system, then properly refill the cooling system with a 50/50 mixture of fresh coolant (antifreeze and water), as follows:
- Fill the radiator with coolant mixture until it reaches the radiator filler neck seat.
- Start the engine and allow it to idle (heater on) until the thermostat opens (the upper radiator hose will become hot).
- Turn the engine OFF and refill the radiator until the coolant level is at the filler neck seat.
- Fill the overflow tank with the coolant mixture until the level is midway between the upper and lower level marks, then install the radiator cap.
- If available, install a pressure tester and check for leaks. If a pressure tester is not available, run the engine until normal operating temperature is reached (allowing the system to naturally pressurize), then check for leaks.
- Check the level of protection with an antifreeze/coolant hydrometer.
- After the system has cycled between operating temperature and cold a couple of times, check the overflow tank level and top up if needed.