David,
When you get the new pump in, check the position of the impellor on the shaft. Reference to my picture on preceding page, the impellor was not pressed on the shaft far enough, it was flush with the end of the shaft. The impellor was not sitting in the recess of the pump housing properly. It was too far out on the shaft for the divider plate to fit. Your unit may or may not have to be adjusted. Someone may just have done mine on Friday afternoon. Feel free to holler when you need to.
I am not familiar with the Thermal or Non-Thermal designation. Could they mean Thermal or Friction clutch? Below is the clutch info from the 67 Pontiac manual, so you can understand the operation of the fan clutch.
THERMOSTATICALLY CONTROLLED ENGINE
FAN FLUID CLUTCH
A thermostatically controlled engine fan fluid clutch is used on Air conditioned equipped cars and operates only when additional air flow is required to reduce radiator coolant temperatures.
This clutch is of simple functional design and is made of lightweight metal filled with silicone oil which is hermetically sealed. The finned (rear) housing contains a hub assembly (secured to the housing bearing) which attaches to the engine water pump. Four bosses with tapped holes (in the rear face) provide for attachment of the engine fan. The front surface of the housing has six deep circular grooves which index with six matching bosses on the rear face of a floating clutch. A separator plate and front cover (with thermostatic coil control) complete the clutch assembly.
FUNCTION
During periods of operation when radiator discharge air temperature is low (below approximately 150°F.), the fan clutch limits the fan speed to 800-1400 rpm. In this position, the clutch is disengaged since a small oil pump driven by the separator plate forces the silicone oil into the reservoir between the separator plate and the front cover assembly. In this position also, the passage from this cavity to the clutch area is closed by the coil spring leaf valve.
As operating conditions produce a high radiator discharge air temperature (above approximately
150°F.), the temperature sensitive bi-metal coil tightens to move the leaf valve (attached to the coil)which opens a port in the separator plate, allowing flow of silicone oil into the clutch chamber to engage clutch, providing a maximum fan speed of approximately 2200 rpm.
The clutch coil is calibrated so that a road load with an ambient temperature of approximately 90°F.,the clutch is just at a point of shift between high and low fan speed.
No attempt should be made to disturb the calibration of the engine fan clutch assembly as each assembly is individually calibrated at the time of manufacture.
Under certain temperature conditions there is an apparent lateral movement at the fan tip which should not be considered as a hub or bearing failure. This condition is a design feature of the clutch assembly which allows up to approximately 1/4" lateral movement measured at the fan tip.
NOTE: Testing a fan clutch by holding the small hub with one hand and rotating the aluminum hous
ing in a clockwise/counterclockwise motion will cause the clutch to freewheel, which is a normal
condition when operated in this manner. This should not be considered a test by which replace
ment is determined.
Hope this helps you to decide. Why not change just your pump first to see what good you did there, and then change the clutch if you still need it? Do you feel good air flow from the fan now or not?
Good Luck
Charles
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