F 350 2WD Pickup V8-460 7.5L VIN G EFI (1997)
Fan Clutch: Testing and Inspection
With A/C
Spin the fan. 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:
DISENGAGED FAN CLUTCH REQUIREMENT TEST-COLD
1. Using a suitable marker, mark the water pump pulley, one of the fan blade retaining bolts and the crankshaft pulley.
WARNING: TO AVOID THE POSSIBILITY OF PERSONAL INJURY OR DAMAGE TO THE VEHICLE DO NOT OPERATE THE
ENGINE UNTIL THE FAN HAS BEEN FIRST EXAMINED FOR POSSIBLE CRACKS AND SEPARATION.
2. Connect a tachometer to the engine.
3. Install a throttle adjusting tool.
4. Connect a Sun Strobe Light or equivalent. This can be an SLT-1 or SLT-2 Strobotach or an STA-1 Strobe Trigger adapter for the Sun Distributor
Test Stand. A Digital Photoelectric Tachometer 055-00108 or equivalent can also be used for this test.
5. Start the engine and run it at approximately 1500 rpm until engine temperature has normalized.
6. Adjust the engine to the testing speed of 2,400 rpm.
7. Operate the strobe light at water pump test speed of 3,000 rpm and aim it at the water pump pulley. Adjust the engine speed until the light flashes
and the water pump pulley marks are synchronized.
8. Aim the timing light at the fan retaining bolts. Adjust the strobe light until it is synchronized with the marked fan retaining bolt (fan appears to
stand still).
9. The fan speed must not be greater than the specified fan test speed of 1,900 rpm @ 141°F at water pump test speed of 3,000 rpm
10. Turn the engine OFF
11. If the fan speed was greater than the specified fan test speed of 1,900 rpm @ 141°F, check for proper parts usage.
If the correct parts are used, replace the fan clutch.
If the part(s) are not the correct ones, replace the part(s) and perform the test again.
12. If the Engaged Fan Clutch Requirement Test is going to be performed, do not remove the tachometer, strobe light or throttle adjusting tool.
13. If an Engaged Fan Clutch Requirement Test is not going to be performed, remove the tachometer, strobe light and throttle adjusting tool.
ENGAGED SPEED FAN CLUTCH REQUIREMENT TEST
1. If the Disengaged Fan Clutch Requirement Test was not performed, follow Steps 1 through 5 under Disengaged Speed Fan Clutch Requirement
Test.
WARNING: TO AVOID THE POSSIBILITY OF PERSONAL INJURY OR DAMAGE TO Tide VEHICLE, DO NOT OPERATE THE
ENGINE WITH THE HOOD OPEN UNTIL THE FAN HAS BEEN FIRST EXAMINED FOR POSSIBLE CRACKS AND
SEPARATION.
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 blade to operate at maximum speed.
3. Place the air conditioning selector, if so equipped, in the maximum position and the blower switch in the high position.
4. Adjust the strobe light to water pump test speed of 3,000 rpm
5. Start the engine and adjust it until the water pump pulley is synchronized with the strobe light. This will be near the engine testing speed of 2,400
rpm.
6. Synchronize the timing light with the fan to fan clutch retaining bolt.
7. The fan speed must meet or exceed the specified minimum fan blade test speed of 2,600 rpm @ 211°F at water pump test speed of 3,000 rpm.
8. If the fan speed was less than the specified fan test speed of 2,600 rpm @ 211°F, replace the fan clutch.
