COUPLING-FEMALE 3515220 - Caterpillar

Cylinder Head Bolt Torque Information
All 1100, 3100 and earlier 3200 Series Engines used cylinder head bolts with a torque specification of 130 N m (95 lb ft).
These earlier head bolts can be identified by six dash marks on the bolt head. See Illustration 1.
Later 3204 and 3208 Engines use stronger cylinder head bolts with a higher torque specification. These bolts can be identified by seven dash marks on the bolt head. See Illustration 1.
The higher cylinder head bolt torque may be used on earlier engines ONLY if the bolts are replaced with the later higher strength bolts (seven dash marks on the bolt head). If the earlier bolts are tightened to the later torque specification, they may yield (stretch) and lose their clamping force.
Illustration 1. Bolt Head Identification.Before installing the cylinder head bolts put engine oil on the threads. Tighten the bolts as shown in Illustration 2 and the Head Bolt Chart.
Illustration 2. Cylinder Head Bolt Tightening Sequence.