Ford Pick-Ups/Bronco 1976-1986 Repair Guide

Cooling System


See Figures 1, 2, 3 and 4

Never remove the radiator cap under any conditions while the engine is running! Failure to follow these instructions could result in damage to the cooling system or engine and/or personal injury. To avoid having scalding hot coolant or steam blow out of the radiator, use extreme care when removing the radiator cap from a hot radiator. Wait until the engine has cooled, then wrap a thick cloth around the radiator cap and turn it slowly to the first stop. Step back while the pressure is released from the cooling system. When you are sure the pressure has been released, press down on the radiator cap (still have the cloth in position) turn and remove the radiator cap.

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Fig. Fig. 1: Cooling system with a coolant recovery bottle

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Fig. Fig. 2: Check antifreeze protection with an inexpensive tester.

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Fig. Fig. 3: Coolant level check

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Fig. Fig. 4: The system should be pressure tested once a year.

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 too much water, it won't protect against freezing.

The pressure cap should be looked at for signs of age or deterioration. Fan belt and other drive belts should be inspected and adjusted to the proper tension. (See checking belt tension).

Hose clamps should be tightened, and soft or cracked hoses replaced. Damp spots, or accumulations of rust or dye near hoses, water pump or other areas, indicate possible leakage, which must be corrected before filling the system with fresh coolant.


See Figure 5

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Fig. Fig. 5: Check the radiator cap gasket for cracks or wear.

While you are checking the coolant level, check the radiator cap for a worn or cracked gasket. It the cap doesn't seal properly, fluid will be lost and the engine will overheat.

Worn caps should be replaced with a new one.


See Figure 6

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Fig. Fig. 6: Keep the radiator fins clear of debris for maximum cooling.

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.


See Figures 7 and 8

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Fig. Fig. 7: Open the radiator petcock to drain the cooling system. Spray first with penetrating oil.

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Fig. Fig. 8: On vehicles without a coolant recovery system, fill the radiator as shown

Completely draining and refilling the cooling system every two years at least will remove accumulated rust, scale and other deposits. Coolant in late model trucks is a 50/50 mixture of ethylene glycol and water for year round use. Use a good quality antifreeze with water pump lubricants, rust inhibitors and other corrosion inhibitors along with acid neutralizers.

  1. Drain the existing antifreeze and coolant. Open the radiator and engine drain petcocks, or disconnect the bottom radiator hose, at the radiator outlet.

Before opening the radiator petcock, spray it with some penetrating lubricant.

  1. Close the petcock or reconnect the lower hose.
  3. Add a can of quality radiator flush and fill the system with water.
  5. Idle the engine until the upper radiator hose gets hot.
  7. Drain the system again.
  9. Repeat this process until the drained water is clear and free of scale.
  11. Close all petcocks and connect all the hoses.
  13. If equipped with a coolant recovery system, flush the reservoir with water and leave empty.
  15. Determine the capacity of your coolant system (see capacities specifications). Add a 50/50 mix of quality antifreeze (ethylene glycol) and water to provide the desired protection.
  17. Run the engine to operating temperature.
  19. Stop the engine and check the coolant level.
  21. Check the level of protection with an antifreeze tester, replace the cap and check for leaks.