Engine Cooling: Diagnosis Lincoln LS I

Inspection and Verification

Scheme 50

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. CAUTION: The cylinder head temperature sensor is not reusable after removal on 3.9L engines. For electrical concern testing see «SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV»(ref-132995) .
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. If Motorcraft Premium Engine Coolant (green-color) VC-4-A or equivalent meeting Ford specification ESE-M97B44-A has a clear, light green or blue color, this indicates higher water content than required. If Motorcraft Premium Gold Engine Coolant (yellow-color) VC-7-A or equivalent meeting Ford specification WSS-M97B51-A1 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 System Stop Leak Powder, part number E6AZ-19558-A (and RA-2) or equivalent meeting Ford specification ESE-M99B170-A except as noted in ES-F6SE-19A511-AA. 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 Engine Coolant or Premium Engine Gold Coolant. An iridescent sheen on the surface of the coolant could indicate a trace of oil is entering the system. For additional information on engine diagnosis, see «ENGINE SYSTEM - GENERAL INFORMATION»(ref-177124) . 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, see «COMPONENT TEST»(ref-177126-S08550577392005062000000) . If engine oil is suspected, the cause of the leak may be internal to the engine. For additional information on engine diagnosis, see «ENGINE SYSTEM - GENERAL INFORMATION»(ref-177124) . If transmission fluid is contaminated with engine coolant, the cause may be a leaky radiator, pressure test the system. For additional information, see «COMPONENT TEST»(ref-177126-S08550577392005062000000) . If the engine coolant appearance is acceptable, test the engine coolant freezing point range with the Battery/Antifreeze 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 the coolant is low, add specified coolant mixture only. If the coolant tests weak, add straight engine coolant until the readings are within acceptable levels. If the coolant tests strong, remove some of the engine coolant and add 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.
6. Verify the cooling system is correctly filled and bled. For additional information, see «COOLING SYSTEM DRAINING, FILLING AND BLEEDING»(ref-177126-S33156574382005062000000) .

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Pressure Test

1. Turn the engine OFF.
2. Remove the cowl vent screen.
3. Check the engine coolant level. For additional information, see «COOLING SYSTEM DRAINING, FILLING AND BLEEDING»(ref-177126-S33156574382005062000000) .
4. 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.
5. Slowly depress the plunger of the pressure test pump until the pressure gauge reading stops increasing and note the highest pressure reading obtained.
6. 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.
7. If 8-9 kPa (13 psi) cannot be reached, install a new pressure relief cap. If more than 12 kPa (18 psi) shows on the gauge, install a new pressure relief cap.
8. 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; see «GENERAL SPECIFICATIONS»(ref-177126-S20798257002005062000000) . Pressure should not drop during this time.
9. 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, see «COOLING SYSTEM DRAINING, FILLING AND BLEEDING»(ref-177126-S33156574382005062000000) .

Radiator Leak Test, Removed From the 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 tank.

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