Chapter 8 - caterpillar engine and related systems – Cub Cadet 4 x 4 Volunteer User Manual
Page 252

Chapter 8 - Caterpillar Engine and Related Systems
248
9c. Use the non-contact thermometer to moni-
tor the temperature in two spots as the 
engine warms-up from a cold start: 
Check the engine block adjacent to the 
water pump. 
Check the to-radiator pipe.  
See Figure 8.72.
9d. Interpretation:
•
If the two temperatures follow each-other 
closely, the thermostat has been removed or has 
failed in the open position.
•
If the block temperature steadily rises past 160 
deg.f. (71 deg.c.), and the temperature in the 
pipe does not make a rapid shift upward, the 
thermostat has failed in the closed position or 
coolant is not circulating because of some other 
problem (belt, water pump, obstruction).
•
If the block temperature rises to nearly 160 deg. 
f. (71deg.c.) and the to-radiator pipe remains 
cool until that point then suddenly rises to the 
same temperature, the thermostat is operating 
correctly. 
NOTE: The thermostat opens at 167 deg. f. (75 
deg.c.), but the insulating properties of the metal 
reduce the surface reading. There is a weep 
hole in the body of the thermostat to allow some 
movement of coolant, even when the thermostat 
is closed. See Figure 8.73.
NOTE: The correct direction for thermostat 
installation is with the copper-colored wax-stat 
section facing into the water jacket of the engine. 
If installed wrong-way-round it will not open at 
the correct temperature. See Figure 8.74.
Figure 8.72
Figure 8.73
Weep hole
Figure 8.74
 Thermostat
 housing
 NOTE:
 correct 
 positioning
 of the
 thermostat 
