pressure reading. Release pressure and repeat the test. Install a new radiator cap if the
pressure is not 99.3-
121.4 kPa (14.4-17.6 psi).
Cap — 4.6L
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).
1. Remove the pressure relief cap from the degas bottle.
2. Follow the instructions from the pressure tester.
3. 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.
4. 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.
Thermostat — Water
A new water thermostat should be installed only after the following electrical and mechanical tests
have been carried out.
Thermostat — Electrical Test
CAUTION: Always vent the exhaust to the outside when carrying out this test.
NOTE: The electrical thermostat test is most accurate if carried out at less than 37.8°C (100°F)
ambient air. This test may be carried out with or without the hood open and with the engine warm or
cold.
1. Check the engine coolant level. Fill as needed.
2. With the ignition OFF, remove the engine coolant temperature (ECT) (4.6L) or cylinder head temperature (CHT) (3.8L) sensor harness connector and attach ECT (4.6L) or CHT (3.8L)
Sensor "T" Cable as a jumper between the powertrain control module (PCM) (12A650) and the
ECT (4.6L) or CHT (3.8L) sensor. Attach the 73III Automotive Meter to the ECT (4.6L) or CHT
(3.8L) Sensor "T" Cable. Voltage values (0- 5 V) may now be monitored while the sensor retains
its connection to the wiring harness.
An appropriate diagnostic tool may be used to monitor the ECT on vehicles equipped with data link connector (DLC). Klj . 8 ba
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3. Remove the pressure cap from the cooling system reservoir and the fill plug from the engine
crossover tube.
4. CAUTION: Do not fill the cooling system through the reservoir only. Coolant will not
enter the engine. Only the reservoir and the radiator will be filled and engine overheating
will occur.
Add coolant into the fill neck on the engine crossover tube until coolant reaches the top of the fill
neck on the cooling system reservoir.
5. Install the cooling system pressure cap on the reservoir.
6. Continue to fill the cooling system at the engine crossover fill neck until full.
7. Install the engine crossover tube fill plug.
8. WARNING: To avoid the possibility of personal injury or damage to the vehicle, do
not operate the engine with the hood open until the fan has been first examined for
possible cracks and separation.
CAUTION: If the engine temperature gauge does not move, coolant level is low in
the engine and must be filled. Stop the engine, allow to cool, and fill the cooling system
as outlined.
Run the engine until the thermostat opens (coolant flowing through the radiator lower hose
becomes hot).
9. Stop the engine and allow to cool.
10. Add coolant to the engine crossover tube fill neck until the cooling system is full.
11. Install the fill plug.
12. Repeat the fill procedure if necessary.
Filling — Mach I
CAUTION: Vehicle cooling systems are filled with Motorcraft Premium Gold Engine
Coolant VC -7-A (in Oregon VC -7-B) or equivalent meeting Ford specification WSS- M97B51-A1
(yellow color). Always fill the cooling system with the same coolant that is present in the
system. Do not mix coolant types.
CAUTION: Engine coolant provides freeze protection, boil protection, cooling efficiency,
and corrosion protection to the engine and cooling components. In order to obtain these
protections, the engine coolant must be maintained at the correct concentration and fluid level
in the degas bottle.
When adding engine coolant, use a 50/50 mixture of engine coolant and deionized water.
To maintain the integrity of the coolant and the cooling system:
zAdd Motorcraft Premium Gold Engine Coolant VC -7-A (in Oregon VC -7-B) or equivalent
meeting Ford specification WSS- M97B51-A1 (yellow color). Use the same coolant that Klj . 5 ba
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