PISTON-SEMI 3B5172 - Caterpillar

TECHNICAL INFORMATION BULLETIN November 21, 2005
C7 and C9 On-Highway Truck Engines C7 (FML, FMM, KAL, YPG)
C9 (9DG, C9S, MTB)
Component Code(s) 1355, 7498SUBJECT: TEMPERATURE REGULATORS ARE STICKING OPEN CAUSING LOW COOLANT TEMPERATURE AND ENGINE COLD MODE OPERATION TO STAY ACTIVE
PROBLEM:
On C7 and C9 On-highway Truck Engines the (1) jiggle pin in the 115-4223 Water Temperature Regulator may stick between the regulator valve and the regulator seat. When this condition occurs the engine may not reach normal operating temperatures and/or the engine will stay in cold mode operation.
SOLUTION:
If the (1) jiggle pin is found trapped in the regulator valve, replace the 115-4223 Water Temperature Regulator with another 115-4223 Water Temperature Regulator. Make sure to orient the 115-4223 Water Temperature Regulator in a position that will prevent the (1) jiggle pin from being pulled by gravity and towards the thermostat seal. In C9 engines the Water Temperature Regulator is installed in a 45? angle. Make sure that the (1) jiggle valve is installed in the six o?clock position.
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