We recommend that the propylene glycol anti-freeze that comes in all of our 6.2L Ford based engines gets replaced after two seasons of use. Drain the coolant from the system by removing the pressure cap from the high fill bottle then removing the hose indicated in the photograph below.
Prepare the replacement coolant by mixing the appropriate amount of concentrated anti-freeze and water in a clean container. The system holds approximately 12-14 quarts. A 50:50 mix like we use gives you freeze protection to -28 degrees F (-33.3 C) and burst protection to -75 degrees F (-59.4 C).
Replace the hose you removed to drain the system and disconnect the heater hose from the fitting closest to the alternator as indicated in the photograph below.
Pour coolant into the system through the high-fill bottle till coolant comes out of the heater inlet tube. Reconnect the heater hose to the heater inlet tube.
Fill the high-fill bottle to the MAX fill line, Install the cap on the high-fill bottle and back it off one full turn.
Apply water to the engine’s raw water cooling system and start the engine and let it idle for two minutes. Increase the engine RPM to 3000 and let the engine run till the engine comes up to operating temperature, between 153 and 163 Degrees F. Bring the engine back to idle RPM. Determine if the thermostat has opened by feeling the coolant (anti-freeze) hoses at the top and bottom of the heat exchanger. If these hoses are warm, the thermostat has opened.
If the coolant level in the high-fill bottle had dropped, add coolant to the MAX line and replace the cap. Run the engine at 3000 RPM for an additional two minutes. The coolant level should stabilize.
Shut the engine off and let it cool, preferably overnight. As the engine cools, the coolant level in the high-fill bottle will drop. With the engine cooled to room temperature, adjust the coolant level in the high-fill bottle above the MIN line. Replace and tighten the cap and you should be done.