2011/10/31 Caterpillar

Generator Set:

C175-16 (S/N: WYB1-UP)

Engine:

C175-16 (S/N: P6L1-UP)

Description of Change: The new bolts for the pressure relief valve on the high-pressure fuel pump are more resistant to corrosion than the previous bolts.

Adaptable To:

Illustration 1	g02746359
Bolt for the pressure relief valve on the high-pressure fuel pump

The 8T-4178 Bolt is adaptable to the above engines back to first production. The bolts are effective with the serial numbers that are listed in Table 1

Bolt Tightening Procedure

The 8T-4178 Bolt is used with the 8T-4121 Hard Washer. Both of the parts are serviceable in case service is needed for the pressure relief valve on the high-pressure fuel pump.

The 8C-3078 O-Ring Seal is also available for use with the pressure relief valve. Always use a new O-ring seal when you install a valve.

Use the following procedure to tighten the bolts:

Illustration 2	g02746460
Bolt tightening sequence

1. Tighten the bolts in sequence to 20 N·m (15 lb ft).

2. Tighten the bolts in the same sequence to 40 N·m (30 lb ft).

3. Tighten the bolts in the same sequence to 60 N·m (45 lb ft).

4. Verify that the bolts are tightened to 60 N·m (45 lb ft).