Service manual specification for the piston-to-bore clearance needs to be corrected. Following is the current model year correction, along with a restatement of past model years:
Piston-to-bore clearance = .001" - .0022" (.025mm - .055mm)
Piston-to-pin clearance = .0004" - .0009" (.010mm - .022mm)
Piston-to-bore clearance = .0007" - .0017" (.017mm - .043mm)
Piston-to-pin clearance
1982-1984 = .0003" - .0004" (.007mm - .009mm)
1985-1986 = .0002" - .0007" (Production) (.005mm - .0l0mm)
1985-1986 = .0004" - .0009" (Revised Service Parts) (.010mm - .022mm)
Please take appropriate action to correct your service manual and inform your service personnel.
This bulletin is for information only.
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.