2012/08/03 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 Design

The 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.