Engine Cooling System: Diagnosis Ford Ranger I

Inspection & Verification

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. VISUAL INSPECTION Mechanical Electrical Leaks Damaged Hoses Loose/Damaged Hose Clamps Damaged Water Thermostat Gasket Damaged Head Gaskets Damaged Intake Manifold Gasket Damaged Water Pump Damaged Radiator Coolant Recovery Reservoir Damaged Heater Core Damaged Fan/Fan Clutch Damaged Engine Coolant Temperature Sensor Damaged Wiring
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 VC-4-A or equivalent meeting Ford specification ESE-M97B44-A (Green color) has a Clear, Light Green or Blue color, this indicates higher water content than required. If Motorcraft Premium Gold Engine Coolant VC-7-A or equivalent meeting Ford specification WSS-M97B51-A1 (Yellow color) has a Clear or Pale Yellow color, this indicates higher water content than required. NOTE: The addition of Motorcraft Cooling System Stop Leak Pellets, VC-6, darkens Motorcraft Premium Gold Engine Coolant from Yellow to Golden Tan. 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 ESE-M99B32-B5 except as noted in ES-F65E-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. 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 - RANGER»(ref-204976) . 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-204985-S06910589152005111600000) . 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 - RANGER»(ref-204976) . 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-204985-S06910589152005111600000) . If the engine coolant appearance is acceptable, test the engine coolant freezing point range with the battery and 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 to 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 water until the readings are within acceptable levels.
5. If the concern remains after the inspection, determine the symptom(s). GO to «SYMPTOM CHART»(ref-204985-S22838620202005111600000) .

SYMPTOM CHART

ENGINE COOLING SYMPTOM

Scheme 2

Scheme 3

Scheme 4

Scheme 5

Scheme 6

Pressure Test

1. Remove the radiator cap or degas bottle cap. Fill the radiator as needed. Fit the pressure tester to the radiator neck or degas bottle using an aftermarket adapter.
2. Pump the cooling system to a maximum of 102 kPa (14.9 psi) and hold for two minutes. If the pressure drops within this time, inspect for leaks and repair as necessary.

THERMOSTAT - ELECTRICAL TEST

Note. The electrical thermostat test is most accurate if carried out indoors 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) sensor harness connector and attach ECT Sensor "T" Cable as a jumper between the powertrain control module (PCM) (12A650) and the ECT Sensor. Attach the 73 Digital Multimeter to the ECT Sensor "T" Cable. Voltage values (0-5 V) may now be monitored while the sensor retains its connection to the wiring harness. A scan tool may be used to monitor the ECT on vehicles equipped with Data Link Connector (DLC).
3. Place the transmission in PARK (P) or NEUTRAL (N).
4. Start the engine and allow the engine to idle throughout this test. Allow the engine to run for two minutes, then record the ECT voltage. Record the ECT voltage every 60 seconds. When the ECT voltage trend changes direction or only changes slightly (0.03 volt or less) from the previous reading, record this as the thermostat opening voltage. Use the voltage and corresponding coolant temperature chart listed below. VOLTAGE & COOLANT TEMPERATURE Coolant Temperature °C (°F) ECT (Volts) 22 (71) 3.00 43 (109) 2.01 71 (159) 1.01 82 (180) 0.75 91 (195) 0.059 97 (206) 0.050 105 (221) 0.040
5. If the thermostat opening voltage is greater than 0.58 volt and less than 90°C (194°F), install a new water thermostat.
6. If the thermostat opening voltage is less than 0.58 volt and greater than 90°C (194°F), the water thermostat is good and a new thermostat should not be installed. GO to «SYMPTOM CHART»(ref-204985-S22838620202005111600000) for further instructions.

THERMOSTAT - MECHANICAL TEST, 3.0L & 4.0L ENGINES

1. Remove the water thermostat.
2. Check the water thermostat for seating. Hold the water thermostat up to a lighted background. Leakage of light around the thermostat valve at room temperature indicates that a new water thermostat should be installed. Some water thermostats have a small leakage notch at one location on the perimeter of the thermostat valve, which is considered normal.
3. Immerse the water thermostat in a boiling antifreeze and water mixture.
4. See «GENERAL SPECIFICATIONS»(ref-204985-S07454866482005111600000) chart for water thermostat opening temperatures.

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 tank.

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

FAN CLUTCH TEST

1. Spin the fan blade (8600) 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

Fan Clutch Test - Minimum Speed Requirement

1. Use a suitable marker to mark the water pump pulley (8509), one of the fan blade retaining bolts and the crankshaft pulley (6312).
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. Operate the digital photoelectric tachometer at 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 digital photoelectric tachometer at the fan blade bolts. Adjust the strobe light until the light flash is synchronized with the marked fan blade bolt (the 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 (8A616).

Fan Clutch Test - Maximum Speed Requirement

1. Carry out Steps 1 through 5 of the Fan Clutch Test - Minimum Speed Requirement.
2. Block off areas on each side of the radiator in the engine compartment and the front of the radiator grille (8200). This will raise the temperature of the air striking the fan clutch and should cause the fan blade to operate at maximum speed.
3. Place the climate control function selector switch in the MAX A/C position and the blower motor switch in the HI position.
4. Adjust the strobe to 3,000 RPM.
5. Start the engine and adjust the engine speed until the digital photoelectric tachometer light and the water pump pulley mark are synchronized.
6. Aim the digital photoelectric tachometer light at the fan blade retaining bolts. Adjust the digital photoelectric tachometer light until the light flash is synchronized with the marked fan blade bolt (the fan blade appears to stand still).
7. If the fan blade speed is less than 2,300 RPM, install a new fan clutch.

Scheme 7