Ford 2003 Mustang Workshop Manual page 1850

1. Turn the engine OFF.
2. WARNING: Never remove the pressure relief cap while the engine is operating or
when the cooling system is hot. Failure to follow these instructions can result in damage
to the cooling system or engine or personal injury. To avoid having scalding hot coolant
or steam blow out of the degas bottle when removing the pressure relief cap, wait until
the engine is cooled, then wrap a thick cloth around the pressure relief cap and turn it
slowly. Step back while the pressure is released from the cooling system. When you are
sure all the pressure has been released, turn and remove the pressure relief cap (still
with a cloth).
Check the engine coolant level; refer to
section.
3. Connect Radiator Heater Core Pressure Tester to the degas bottle nipple and vent hose. Install
a pressure test pump to the quick-connect fitting of the test adapter.
4. CAUTION: Do not pressurize the cooling system beyond 152 kPa (22 psi).
NOTE: If the plunger of the pump is depressed too quickly, an erroneous pressure reading will
result.
Slowly depress the plunger of the pressure test pump until the pressure gauge reading stops
increasing and note the highest pressure reading obtained.
5. If the pressure relief cap does not hold pressure, remove and wash the pressure relief cap in
clean water to dislodge all foreign particles from the gaskets. Check the sealing surface in the
filler neck.
6. If 110 kPa (16 psi) cannot be reached, install a new pressure relief cap. If more than 124 kPa
(18 psi) shows on gauge, install a new pressure relief cap.
7. CAUTION: If the pressure drops, check for leaks at the engine-to-heater core hoses,
engine-to-radiator hoses, water valve hose (if applicable), oil cooler return tube gasket
(6N789), radiator and heater core or other system components and connections. Any
leaks which are found must be corrected and the system rechecked.
Pressurize the engine cooling system as described in Step 4 (using a pressure relief cap that
operates within the specified upper and lower pressure limits). Observe the gauge reading for
approximately two minutes; refer to General Specifications. Pressure should not drop during this
time.
8. Release the system pressure by loosening the pressure relief cap. Check the engine coolant
level and replenish, if necessary, with the correct engine coolant mixture; refer to
System Draining, Filling and Bleeding
Cap — 3.8L
1. Inspect the radiator cap and seals for damage or deterioration. Install a new radiator cap if
necessary.
2. Fit the radiator cap to Radiator/Heater Core Pressure Tester Kit, using the aftermarket adapter.
3. NOTE: If the plunger of the pressure tester is depressed too fast, an incorrect pressure reading
will result.
Slowly pump the pressure tester until the pressure gauge stops increasing and note the highest
Cooling System Draining, Filling and Bleeding
in this section.
in this
Cooling