Engine Cooling System: Diagnosis Ford Taurus IV facelift

Inspection and Verification

Note. The addition of Motorcraft Cooling System Stop Leak Pellets, VC-6, darkens Motorcraft Premium Gold Engine Coolant from yellow to golden tan.

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1. Verify the customer's 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 it as necessary.
4. Inspect the coolant condition. Inspect the coolant color: NOTE: The addition of Motorcraft Cooling System Stop Leak Pellets, VC-6, darkens Motorcraft Premium Gold Engine Coolant from yellow to golden tan. 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 can 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 only. 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 clean distilled water and engine coolant. An iridescent sheen on top of the coolant can indicate a trace of oil is entering the system. For additional information on engine diagnosis, refer to «ENGINE SYSTEM-GENERAL INFORMATION»(ref-212097) . 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. Refer to «COMPONENT TESTS»(ref-212100-S25054240092005122300000) . If engine oil is suspected, the cause of the leak may be internal to the engine. For additional information on engine diagnosis, refer to «ENGINE SYSTEM-GENERAL INFORMATION»(ref-212097) . If transmission fluid is contaminated with engine coolant the cause may be a leaky radiator, pressure test the system. Refer to the «COMPONENT TESTS»(ref-212100-S25054240092005122300000) . 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 -50°F to -10°F. If the vehicle is driven in cold climates less than -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 coolant is low, add specified coolant mixture only. If the engine coolant tests too 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 clean distilled water until the readings are within acceptable levels.
5. Verify the cooling system is correctly filled and bled. Refer to «COOLING SYSTEM DRAINING, FILLING AND BLEEDING»(ref-212100-S06677154962005122300000) .
6. If DTC P1474, P1477 or P1479 are present, refer to the «INTRODUCTION - CNG, FLEX-FUEL & GASOLINE»(ref-225317) article for diagnosis.
7. If the concern remains after the inspection, determine the symptom(s). GO to «SYMPTOM CHART»(ref-212100-S36221520762005122300000) .

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Pressure Test

1. Turn the engine OFF.
2. Check the engine coolant level. Refer to «COOLING SYSTEM DRAINING, FILLING AND BLEEDING»(ref-212100-S06677154962005122300000) .
3. Connect the 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. Pressure check the pressure relief cap. If 8-9 kPa (13 psi) cannot be reached or if more than 12 kPa (18 psi) show 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; refer to «GENERAL SPECIFICATIONS»(ref-212100-S07643659232005122300000) . 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 «COOLING SYSTEM DRAINING, FILLING AND BLEEDING»(ref-212100-S06677154962005122300000) .

Radiator Leak Test, Removed From the Vehicle

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

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

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

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