Radiator Cooling Fan Pump: Testing and Inspection

1. Using a cleaner and compressed air, clean the disassembled parts.

NOTE: Thoroughly clean the oil passages of the rear housing. Oil passage A includes 8 filter which should be cleaned carefully.





2. Inspect spool valve.
(a) Coat the spool valve with fluid, and check that it falls smoothly into the spool sleeve by its own weight.





(b) Check the spool valve for leakage. Close one of the holes and apply compressed air 392 - 490 kPa (57 - 71 psi) into the opposite side, check that air does not come out of the end hole. If it doesn't, replace the spool valve and sleeve as a set.





3. Inspect spool compression spring and using vernier calipers, measure the free length. The free length is 45.8 mm (1.803 inch). If the free length is not as specified, replace the spring.





4. Inspect drive and driven rotors.
A. Install casing and rotors to rear housing and face the dot mark of the rotors upward.





B. Inspect rotor side clearance.

NOTE: Before measuring the clearance, remove one side of the rotors.

Using a feeler gauge and precision straight edge, measure the side clearance between the rotor and precision straight edge.
Standard side clearance:
Drive rotor: 0.02 mm (0.0008 inch)
Driven rotor: 0.03 mm (0.0012 inch)
Maximum side clearance:
Drive rotor: 0.03 mm (0.0012 inch)
Driven rotor: 0.04 mm (0.0016 inch)
If the clearance is greater than maximum, replace the rotors as a set. If necessary, replace the housings.





C. Inspect rotor body clearance. Using a feeler gauge, measure the clearance between the driven rotor and casing.
Standard body clearance: 0.05 - 0.09 mm (0.0020 - 0.0035 inch)
Maximum body clearance: 0.10 mm (0.0039 inch)
If the clearance is greater than maximum, replace the rotors as a set. If necessary, replace the casing.





D. Inspect rotor tip clearance.
Using a feeler gauge, measure the clearance of all the 6 drive rotor tips between the drive and driven rotors.
Standard body clearance: 0.02 mm (0.0008 inch)
Maximum body clearance: 0.03 mm (0.0012 inch)
If the clearance is greater than maximum, replace the rotors as a set.
E. Remove rotors and casing from rear housing.





5. Inspect oil clearance of drive shaft.
(a) Using a caliper gauge, measure the bushing inside diameter on the housings.
Bushing hole inside diameter: 17.000 - 17.050 mm (0.6693 - 0.6713 inch)
(b) Using a micrometer, measure the drive shaft diameter.
Shaft diameter: 16.370 - 16.980 mm (0.6681 - 0.6685 inch)
(c) Subtract the drive shaft diameter measurement from the bushing inside diameter measurement.
Standard clearance: 0.020 - 0.080 mm (0.0008 - 0.0031 inch)
Maximum clearance: 0.08 mm (0.0031 inch)
If the clearance is greater than maximum, replace the shaft. If necessary, replace the housings.





6. Inspect solenoid valve. Using an ohmmeter, measure the resistance between the terminals.
Resistance: 7.5 - 8.5 ohms at 20° C (68° F). If the resistance is not as specified, replace the sensor.