A revised head bolt torque procedure has been developed for all vehicles equipped with an HT4100 engine. This new procedure supersedes all previously published information.
The revised head bolt torque sequence and bolt torques are shown in the figure below.
1. Torque all bolts in above sequence tu 50 N.m (38 ft. lbs.)
2. Torgue all bolts in same sequence to 100 N.m (74 ft. lbs.)
3. Torque bolts 1, 3 and 4 to 120 N.m (90 ft. lbs.)
This updated procedure should be followed whenex,er cylinder head installation is required.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.