See Figure 1
At least once every 2 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.Checking The Radiator Cap
See Figure 2
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.
DRAIN & REFILL
The system should be completely drained and refilled at least every two years in order to remove accumulated rust, scale and other deposits.
FLUSHING & CLEANING THE SYSTEM
See Figures 3, 4, 5 and 6
- Remove the radiator cap. Drain the existing coolant by opening the radiator draincock and engine draincock (if equipped, located on the water pump housing) or by disconnecting the bottom radiator hose at the radiator outlet.
Before opening the radiator draincock, spray it with some penetrating lubricant.
- Close the draincock or reconnect the lower hose and fill the system with water.
- Add a can of quality radiator flush.
- Idle the engine until the upper radiator hose gets hot.
- Drain the system again.
- Repeat this process until the drained water is clear and free of scale.
- Close all draincocks and connect all the hoses.
- If equipped with a coolant recovery system, flush the reservoir with water and leave empty.
- Determine the capacity of your cooling system (see the Capacities Chart). Add a 50/50 mix of quality antifreeze and water to provide the desired protection.
- Run the engine to operating temperature.