Engine Cooling System: Diagnosis Ford Expedition II

Inspection and Verification

Scheme 2

1. Verify the customer concern by operating the engine to duplicate the condition.
2. Inspect to determine if any of the following mechanical or electrical concerns apply.
3. If the inspection reveals an obvious concern that can be readily identified, repair as necessary.
4. Inspect the coolant condition. Inspect the coolant color. If Motorcraft Premium Gold Engine Coolant VC-7-A (in Oregon VC-7-B) or equivalent meeting Ford specification WSS-M97B51-A1 (yellow color) has a clear or pale yellow color, this indicates higher water content than required. Dark brown could indicate unauthorized stop leak may have been used. Use Motorcraft Cooling System Stop Leak Pellets VC-6 or equivalent meeting Ford specification WSS-M99B37-B6. The addition of Motorcraft Cooling System Stop Leak Pellets, VC-6, darkens Motorcraft Premium Gold Engine Coolant from yellow to golden brown. A light or reddish brown color indicates that rust may be present in the cooling system. Flush the system and refill with the correct mixture of water and Premium Gold Engine Coolant. For additional information, refer to «ENGINE AND RADIATOR FLUSHING»(ref-209901-S03501362832005121200000) . An iridescent sheen on top of the coolant could indicate a trace of oil is entering the system. For additional information on engine diagnosis, refer to «ENGINE SYSTEM-GENERAL INFORMATION»(ref-209898) . A milky brown color may indicate that either engine oil or transmission fluid is entering the cooling system. If transmission fluid is suspected, the cause may be a leaky radiator. Pressure test the cooling system. For additional information, refer to «COMPONENT TESTS»(ref-209901-S21074571972005121200000) . If engine oil is suspected, the cause of the leak may be internal to the engine. For additional information, refer to «ENGINE SYSTEM-GENERAL INFORMATION»(ref-209898) . If transmission fluid is contaminated with engine coolant, the cause may be a leaky radiator. Pressure test the system. For additional information, refer to the «COMPONENT TESTS»(ref-209901-S21074571972005121200000) . If the engine coolant appearance is acceptable, test the engine coolant freezing point range with the Battery/Anti-Freeze Tester. The freezing point should be in the range -23°C to -46°C (-10°F to -50°F). If the vehicle is driven in cold climates less than -37°C (-34°F), it may be necessary to increase the coolant concentration to get adequate freeze protection. Maximum coolant concentration is 60/40. Minimum coolant concentration is 40/60. Adjust coolant range and level if necessary: If the coolant is low, add specified coolant mixture only. If the engine coolant tests weak, add straight engine coolant until the readings are within acceptable levels. If the engine coolant tests strong, remove some of the engine coolant and add distilled water until the readings are within acceptable levels.
5. If the concern remains after the inspection, determine the symptom(s) and go to the «SYMPTOM CHART»(ref-209901-S39137369212005121200000) .

Scheme 3

Scheme 4

Scheme 5

Scheme 6

Pressure Test

1. Turn the engine OFF.
2. Check the engine coolant level. For additional information, refer to «COOLING SYSTEM DRAINING, FILLING AND BLEEDING»(ref-209901-S18813989322005121200000) .
3. Connect Radiator Heater Core Pressure Tester to the degas bottle nipple and overflow hose. Install a pressure test pump to the quick-connect fitting of the test adapter.
4. 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 89 kPa (13 psi) cannot be reached, install a new pressure relief cap. If more than 124 kPa (18 psi) shows on the gauge, install a new pressure relief cap.
7. 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. For additional information, refer to Specifications in this section. 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. For additional information, refer to «COOLING SYSTEM DRAINING, FILLING AND BLEEDING»(ref-209901-S18813989322005121200000) .

Cap-Pressure Relief

1. Inspect the pressure relief cap and seals for damage or deterioration. Install a new pressure relief cap if necessary.
2. Fit the pressure relief cap to Radiator/Heater Core Pressure Tester Kit using the aftermarket adapter.
3. Slowly pump the pressure tester until the pressure gauge stops increasing and note the highest pressure reading. Release pressure and repeat the test. Install a new pressure relief cap if the pressure is not 99.3-121.4 kPa (14.4-17.6 psi).

Radiator Leak Test, Removed From Vehicle

Note. Always install plugs in the oil cooler fittings before leak-testing or cleaning any radiator.

Note. Clean the radiator before leak-testing to avoid contamination of the tank.

Leak-test the radiator in clean water with 138 kPa (20 psi) air pressure.

Mechanical Fan Clutch Test

Spin the fan blade by hand. A light resistance should be felt. If there is no resistance or very high resistance, the minimum and maximum fan speeds must be checked as follows

Minimum Speed Fan Clutch Requirement Test

1. Use a suitable marker to mark the water pump pulley, one of the fan blade bolts, and the crankshaft pulley.
2. Connect a tachometer to the engine.
3. Install a throttle adjusting tool.
4. Connect a digital photoelectric tachometer.
5. Start the engine and run it at approximately 1,500 RPM until the normal operating temperature has been achieved.
6. Adjust the engine speed to 2,300 RPM.
7. Adjust the strobe light to 3,000 RPM and aim it at the water pump pulley. Adjust the engine speed until the light flash and the water pump pulley mark are synchronized.
8. Aim the strobe light at the fan blade retaining bolts. Adjust the strobe light until the light flash is synchronized with the marked fan blade retaining bolt (fan blade appears to stand still).
9. The fan blade speed must not be greater than 1,500 RPM at 3,000 water pump RPM.
10. Turn the engine off.
11. If the fan blade speed was greater than 1,500 RPM, install a new fan clutch.

Maximum Speed Fan Clutch Requirement Test

1. Carry out Steps 1 through 5 of the Minimum Speed Fan Clutch Requirement Test.
2. Block off areas on each side of the radiator in the engine compartment and the front of the radiator grille. This will raise the temperature of the air striking the fan clutch and should cause the fan to operate at maximum speed.
3. Place the climate control function selector switch in the panel mode, A/C request selected, recirculated air request selected and the blower motor switch in the HI position.
4. Adjust the strobe light to 3,000 RPM.
5. Start the engine and adjust the engine speed until the strobe light flash and the water pump pulley mark are synchronized.
6. Aim the strobe light at the fan blade retaining bolts. Adjust the strobe light until the light flash is synchronized with the marked fan blade retaining bolt (fan blade appears to stand still).
7. If the fan blade speed is less than 2,300 RPM, install a new fan clutch.