THERMOSTAT TEST
DIESEL ENGINE–3TNE74-JKI
THERMOSTAT TEST
WATER PUMP/ALTERNATOR DRIVE BELT ADJUSTMENT
Reason: To determine opening temperature of thermostat.
Reason:
Equipment:
To keep proper tension on belt to drive water pump and alternator. To prevent shortened belt and bearing life.
• Thermometer • Glass Container • Heating Unit
Equipment: • JDG529 or JDST28 BeltTension Gauge • Straight Edge
Procedure:
CAUTION
Procedure:
DO NOT allow thermostat or thermometer to rest against the side or bottom of glass container when heating water. Either may rupture if overheated. 1. Suspend thermostat and a thermometer in a container of water. 2. Heat and stir the water. Observe opening action of thermostat and compare temperatures with specifications. 3. Remove thermostat and observe its closing action as it cools.
1. Open hood and remove left side engine cover. 2. Check belt tension between water pump and alternator using Belt Tension Gauge and a straight edge. Belt Tightening Specifications: Applied Force.................................. 98 N (22 lb-force) Deflection . . . . . . . . . 10 – 15 mm (0.400 – 0.600 in.) Results: • If deflection is not within specifications:
Specifications: Begin Opening............... 69.5 – 72.5° C (157 – 163° F) Fully Open .............................................. 85° C (185° F) Minimum Lift Height Above 85° C (185° F) ..................... 8 mm (0.315 in.)
• Loosen top and bottom alternator mounting cap screws. • Apply force only to right side of alternator housing until tension is correct. • Tighten alternator mounting hardware. • Replace engine cover.
Results: • If thermostat does not open according to specifications, replace. • If closing action is not smooth and slow, replace thermostat.
4/5/01
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