ARM ASSEM. (EXHAUST) 4H9811 - Caterpillar

Electric Power Generation:
3512 GEN SET (S/N: ZAF1-UP)
3512B GENSET (S/N: ZAH1-UP; ZAJ1-UP)
3516B GEN SET (S/N: ZAP1-UP)
3516C GEN SET (S/N: SBK1-UP)
C175-16 GEN SET (S/N: WYB1-UP)
Engine:
3512 (S/N: YAK1-UP)
3512B (S/N: YAM1-UP; YAZ1-UP)
3512C (S/N: SBG1-UP)
3516 (S/N: YAS1-UP)
3516B (S/N: YAP1-UP; PBR1-UP; YAR1-UP; ZAR1-UP; YAT1-UP; YAW1-UP)
3516C (S/N: SBJ1-UP)
Description of Change: The new thermostat is pre-set at the factory. The former thermostat has dials for adjustment of the temperature. The new thermostat has improved cycle rate and improved contact performance.Adaptable To: The replacement part numbers for the former part numbers are given in the Table 1. The former thermostat is not canceled.
Table 1
Qty    New Part Number    Former Part Number    Description    
1     378-4327     300-4967     Thermostat    
1     388-6916     307-3274     Thermostat    
1     378-4328     -     Bracket    
2     212-3416     212-3416     Screw    The changes of the new thermostat and former thermostat is shown in Illustration 1 and 2.
Illustration 1 g03038877
Adjustable Thermostat (1) Old Bracket Design
Illustration 2 g03038878
Fixed Thermostat (2) New Bracket DesignThe temperature ranges for the new thermostats is given in Table 2 and temperature ranges for the former thermostats is given in Table 3.Note: Either 378-4327 Thermostat or 388-6916 Thermostat can be used for replacement depending on preferred temperature range.
Table 2
New Thermostats     Fixed Temperature (With a dead band of 30° F)    
378-4327 Thermostat     130° F    
388-6916 Thermostat     150° F    
Table 3
Former Thermostats     Adjustable Temperature (With a dead band of 20° F)    
300-4967 Thermostat     90° F - 130° F    
307-3274 Thermostat     120° F - 160° F    The new thermostats are effective with units build after April 2012.