How to Bleed Air From a Powerstroke Cooling Systemby Don Bowman
The Ford Powerstroke cooling system capacity is 27.5 qts., plus an additional 0.5 qt. if the system has a coolant filter. Properly filled, it should contain four gallons of Dexcool or Ford Gold antifreeze, which would approximate a 50/50 mix of coolant to water. It is important to allow the cooling system to breathe by maintaining a loose radiator cap while servicing, as opposed to closing the cap and allowing the engine to build pressure in the system. Always use extreme care when opening a coolant system filler cap that may contain pressure as bodily injury may result.
Remove the cap on the coolant reservoir. If the reservoir isn't full to the designated full mark, add water until it is. Ford Powerstroke engines do not need to be "burped" of air because they incorporate a "degas" reservoir. Place the cap on the reservoir loosely so no pressure can become trapped.
Start the engine and allow it to reach operating temperature. Watch the temperature gauge and if it strays any higher than 10 degrees above normal, shut the engine down. Allow it to cool for 20 minutes.
Check the coolant reservoir level. If the level is low it is a good sign that the thermostat has opened and the air has been purged. Fill the reservoir to an inch over the full line on the bottle. Start the engine again and watch the temperature and the reservoir. Add water as the level recedes. If the temperature rises with no apparent loss of coolant in the full reservoir, a fault in the system is present. The most probable faults are an incorrectly installed thermostat, faulty thermostat, faulty fan clutch, collapsed hose or plugged radiator.
Start the engine and look at the fan to see if the fan is keeping up with engine speed. If the fan is revolving slowly, the fan clutch is faulty. Look for a collapsed hose on the top or bottom.
Shut the engine off. Feel the radiator on the fan side for cool spots. If one side is cooler than the other, the radiator is not flowing properly. This doesn't happen too often, but is possible. If this is not the problem, the fault is pointing to the thermostat. Remove the upper radiator hose, using the screwdriver to loosen the clamp. Start the engine. If the thermostat is faulty the temperature will rise to the normal temperature but no antifreeze will flow from the top hose. Install the top hose and tighten the clamp.