I have a 1999 36Ft. M/H on a ford Chassis.What I would like to know is'how can I tell if the Eng.cooling fan is working. It just don't seem to me that it is. For one thing I don't hear it kicking in when it had in the past,and now when pulling a grade at hi RPM's the Temp. will increase subtantally.By backing off on the RPM the Temp. will come back down.

 

It sounds like your fan is not working. The conditions you describe are exactly when the fan clutch (engine driven) or the electric fans should kick in.

Need to know what engine you have for specifics on testing the hydrostatic fan clutch. This is the Ford test procedure for a 1995 unit.

Fan Clutch Test

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. WARNING: TO AVOID THE POSSIBILITY OF PERSONAL INJURY OR DAMAGE TO THE VEHICLE, DO NOT OPERATE THE ENGINE (6007) UNTIL THE FAN HAS BEEN FIRST EXAMINED FOR POSSIBLE CRACKS AND SEPARATION.

Using a suitable marker, 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 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 Rotunda Digital Photoelectric Tachometer 055-00108 or equivalent may 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 in the Specifications at the end of this section.

7. Operate the strobe light at water pump test speed 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 at water pump test speed.

10. Turn the engine OFF.

11. If the fan speed was greater than the specified fan test speed, check for proper parts usage.

If the correct parts are used, replace the fan clutch (8A616).

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 a Engaged Speed Fan Clutch Requirement test is not going to be performed, remove the tachometer, strobe light and throttle adjusting tool.


Maximum Speed Fan Clutch Requirement Test

1. WARNING: TO AVOID THE POSSIBILITY OF PERSONAL INJURY OR DAMAGE TO THE VEHICLE, DO NOT OPERATE THE ENGINE WITH THE HOOD OPEN UNTIL THE FAN HAS BEEN FIRST EXAMINED FOR POSSIBLE CRACKS AND SEPARATION.

If the disengaged fan clutch requirement test was not performed, follow Steps 1 through 5 under Disengaged Fan Clutch Requirement test.

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 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.

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 given in Specifications.

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 at water pump test speed.

8. If the fan speed was less than the specified fan test speed, replace the fan clutch.


Dave / Believer45