1996 Bronco/F-Series

Section 03-03: Engine Cooling

1996 F-150, F-250, F-350, F-Super Duty, Bronco Vehicles and F-250, F-350 and F-Super Duty Vehicles with 7.3L Diesel Engines Workshop Manual

DIAGNOSIS AND TESTING

Pinpoint Tests

PINPOINT TEST A : LOSS OF COOLANT

A1 CHECK COOLANT LEVEL

NOTE: If engine is hot, allow engine to cool down before proceeding.

Check coolant level at radiator coolant recovery reservoir.

Is coolant level OK?

Yes	No
GO to A2.	REFILL as outlined. GO to A2.

A2 CHECK FOR VISIBLE LEAKAGE

Engine coolant has an added dye color, that makes the coolant an excellent leak detector.
Check entire cooling system for visible leakage.

Is there visible leakage?

Yes	No
SERVICE as required. RETEST system.	GO A3.

A3 PRESSURE TEST COOLING SYSTEM

Using Rotunda Radiator/Heater Core Pressure Tester 021-00013 or equivalent, pressurize cooling system as outlined in Pressure Test under Component Tests in this section.

NOTE: Check inside vehicle for possible heater core leakage.

Is there leakage?

Yes	No
SERVICE as required.	GO to A4.

A4 CHECK RADIATOR CAP

Using Rotunda Radiator/Heater Core Pressure Tester 021-00013 or equivalent, test pressure relief radiator cap. Refer to Radiator Cap Pressure Test in Component Tests in this section.

Did radiator cap test OK?

Yes	No
GO toA5.	REPLACE damaged pressure relief cap. RETEST system.

A5 CHECK RADIATOR OVERFLOW HOSE

Remove radiator overflow hose.
Inspect radiator overflow hose for obstruction, cracks or cuts.

Is radiator overflow hose condition OK?

Yes	No
GO to A6.	SERVICE hose as required.

A6 CHECK RESERVOIR

Replenish coolant to Cold level.
Inspect radiator coolant recovery reservoir for leaks.

Is there leakage at radiator coolant recovery reservoir?

Yes	No
REPLACE coolant recovery reservoir. RESTORE vehicle.	GO to A7.

A7 CHECK COOLANT FOR INTERNAL LEAKAGE

Visually inspect coolant in radiator coolant recovery reservoir for signs of transmission or engine oil.

Is oil evident in coolant?

Yes	No
If engine oil is evident on vehicles with an engine oil cooler, REMOVE engine oil cooler and INSPECT for damage. REPLACE if damaged. If engine oil is evident on vehicles without engine oil cooler or if oil cooler checks out OK, REMOVE cylinder head as outlined in Section 03-01A, Section 03-01B, Section 03-01C, or Section 03-01D, depending on engine, and INSPECT for leaking head gasket and head or block cracks. If transmission oil is evident, replace transmission oil cooler in radiator as outlined in this section and check condition of transmission oil as outlined in this section.	GO to A8.

Yes

If engine oil is evident on vehicles with an engine oil cooler, REMOVE engine oil cooler and INSPECT for damage. REPLACE if damaged.

If engine oil is evident on vehicles without engine oil cooler or if oil cooler checks out OK, REMOVE cylinder head as outlined in Section 03-01A, Section 03-01B, Section 03-01C, or Section 03-01D, depending on engine, and INSPECT for leaking head gasket and head or block cracks.

If transmission oil is evident, replace transmission oil cooler in radiator as outlined in this section and check condition of transmission oil as outlined in this section.

GO to A8.

A8 CHECK ENGINE AND TRANSMISSION FOR COOLANT

Remove oil level indicator for engine and transmission.
Carefully inspect oil level indicator for evidence of coolant.

Is coolant evident?

Yes	No
If coolant is in engine oil on vehicles with an engine oil cooler, REMOVE engine oil cooler and INSPECT for damage. REPLACE if damaged. If coolant is evident in engine oil on vehicles without oil cooler or if oil cooler checks out OK, REMOVE cylinder head as outlined in Section 03-01A, Section 03-01B, Section 03-01C, or Section 03-01D, depending on engine, and INSPECT for leaking head gasket and head or block cracks. If coolant is evident in transmission oil, REFER to transmission oil coolant check in Section 07-01A, Section 07-01B, Section 07-01C or Section 03-01D.	Cooling system is OK.

Yes

If coolant is in engine oil on vehicles with an engine oil cooler, REMOVE engine oil cooler and INSPECT for damage. REPLACE if damaged.

If coolant is evident in engine oil on vehicles without oil cooler or if oil cooler checks out OK, REMOVE cylinder head as outlined in Section 03-01A, Section 03-01B, Section 03-01C, or Section 03-01D, depending on engine, and INSPECT for leaking head gasket and head or block cracks.

If coolant is evident in transmission oil, REFER to transmission oil coolant check in Section 07-01A, Section 07-01B, Section 07-01C or Section 03-01D.

Cooling system is OK.

PINPOINT TEST B: ENGINE OVERHEATS

B1 CHECK COOLANT LEVEL

NOTE: If engine is hot, allow engine to cool down before proceeding.

Remove radiator cap and check coolant level at radiator coolant recovery reservoir.

Is coolant level OK?

Yes	No
GO to B2.	REFILL as outlined. REFER to Cooling System, Draining, Filling and Bleeding in the Cleaning and Inspection portion of this section. GO to Pinpoint Test A.

B2 CHECK COOLANT CONDITION

Check coolant for contaminants such as rust or corrosion. Also, check for color discoloration.

Is coolant condition OK?

Yes	No
GO to B3.	FLUSH system. REFER to Cooling System Flush Procedure in the Cleaning and Inspection portion of this section. RETEST system.

B3 CHECK FOR AIRFLOW OBSTRUCTION

Visually inspect A/C condenser core and radiator for obstructions, such as leaves or bugs.

Is there any obstruction?

Yes	No
REMOVE obstruction and CLEAN A/C condenser core and radiator in the Cleaning and Inspection portion of this section. RETEST system.	GO to B4.

B4 CHECK WATER THERMOSTAT OPERATION

Allow engine to run for 10 minutes.
Feel the inlet and outlet heater water hose and the underside of the upper radiator hose.

Are the upper radiator hose and heater water hoses cold?

Yes	No
REPLACE water thermostat. REFER to Thermostat, Water in the Removal and Installation portion of this section. RETEST system.	LEAVE engine RUNNING. GO to B5.

B5 CHECK COOLING FAN

Check for proper cooling fan clutch operation. Perform Fan Clutch Test. Refer to Component Tests in this section.

Did cooling fan clutch operate OK?

Yes	No
CHECK the following: Rust or scale in radiator Water pump shaft and impeller Collapsed lower hose	REPLACE fan clutch. REFER to Cooling Fan Blade and Fan Clutch in the Removal and Installation portion of this section. RETEST system.

PINPOINT TEST C: ENGINE DOES NOT REACH NORMAL OPERATING TEMPERATURE

C1 CHECK FOR FROZEN FAN CLUTCH

Perform fan clutch test as outlined in Component Tests.

Did fan clutch pass test?

Yes	No
GO to C2.	REPLACE fan clutch. REFER to Cooling Fan Blade and Fan Clutch in the Removal and Installation portion of this section.

C2 CHECK THERMOSTAT OPERATION

Remove water thermostat and check opening temperature as outlined in this section.

Does water thermostat begin to open and become fully open at temperatures in the specifications at the end of this section?

Yes	No
REINSTALL water thermostat and CHECK temperature gauge operation as outlined in Section 13-01.	REPLACE thermostat.

PINPOINT TEST D: ENGINE BLOCK HEATER DOES NOT OPERATE PROPERLY

D1 CHECK PLUG AND WIRE

Check for corroded or broken spades on plug.
Check for broken, cracked, or cut wires.
Verify 110-volt AC power source operational.

Are plug and wires OK?

Yes	No
GO to D2.	MAKE necessary repairs. GO to D2.

D2 CHECK CONTINUITY OF PLUG AND WIRES

Disconnect plugs and block heater. Check continuity of wires from plug to element connectors.

Are plug and wires OK?

Yes	No
GO to D3.	REPAIR or REPLACE plugs and wires as necessary. GO to D4.

D3 CHECK RESISTANCE OF BLOCK HEATER

Use Rotunda 73 Digital Multimeter 105-R0051 or equivalent and check for continuity across block heater pins with wires still disconnected.

Is there continuity?

Yes	No
GO to D4.	REPLACE engine block heater. GO to D4.

D4 CHECK OPERATION

Reconnect block heater.
Key to run. Make sure engine is cold (ambient temperature). Key off.
Plug in block heater to known good 120V A/C source and wait 10 minutes.
Key to run. Coolant should be up to 5 to 10°C (40-50°F), bottom of Normal range on gauge.

Has system performed as specified?

Yes	No
System is functional. TERMINATE test.	GO to D5.

D5 CHECK WARNING

Check if block heater is warm.

Is block heater warm?

Yes	No
CHECK operation of vehicle engine coolant temperature gauge. REFER to Section 13-01.	GO to D1.