Ford 2003 Mustang Workshop Manual page 1905

operating. 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
cooling system, use extreme care when removing the pressure relief cap from a hot degas
bottle. Wait until the engine has cooled, then wrap a thick cloth around the pressure relief cap
and turn it slowly one turn (counterclockwise). Step back while the pressure is released from
the cooling system. When certain all the pressure has been released, remove pressure relief
cap (still with a cloth).
1. Immerse the pressure relief cap in water and install it on the shallow filler neck of
Radiator/Heater Core Pressure Tester and Radiator Cap Adapter, part of Radiator/Heater Core
Pressure Tester.
2. Immerse the filler neck seal in water and install it in the filler neck adapter.
3. Install the filler neck adapter with the filler neck seal to the Radiator Cap Adapter.
4. Connect the female quick-connect fitting of the pressure test pump to the male quick-connect
fitting of the filler neck adapter.
5. NOTE: If the plunger of the pump is depressed too fast, 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.
6. Release the pressure by turning the relief screw counterclockwise. Then tighten the pressure
relief screw and repeat Step 6 (at least twice) to make sure the reading is repeatable within the
specifications of the pressure relief cap.
7. If the pressure test gauge readings are not within specifications, install a new pressure relief
cap. If the pressure test gauge readings are within specifications, carry out the cooling system
pressure test.
Radiator Leak Test, Removed From the Vehicle
CAUTION: Never leak test an aluminum radiator or intercooler in the same water that
copper/brass radiators are tested in. Flux and caustic cleaners may be present in the cleaning
tank and they will damage aluminum radiators and intercoolers.
NOTE: Clean the radiator or intercooler before leak testing to avoid contamination of tank.
1. Leak test the radiator or intercooler in clean water with 138 kPa (20 psi) air pressure.