Cylinder Head Bolt - Revised Tightening Procedure
86chevy12Number: 86-2 REISSUE
Section: 6
Date: Sept. 1986
Subject NEW BOLT TIGHTENING PROCEDURE
FOR 2.5L CYLINDER HEAD
Model and Year: 1985 AND 1986 CELEBRITY, CAMARO, CITATION, S/T TRUCKS AND ASTRO VANS (VIN CODES E, R, 2)
TO: ALL CHEVROLET DEALERS
This supercedes all previous 1986 publications dealing with tightening 2.5L cylinder head bolts and cancels previously issued Dealer service Bulletin 86-2 (Section 6A) dated October, 1985 of which all copies should be destroyed.
A new bolt tightening procedure has been developed for the 2.5L engine which improves head to block clamping force and assures more uniform tightening.
The procedure to be used is as follows:
1. Cylinder head bolts should be washed in solvent and dried prior to installation. All residual oil should be wiped from the cylinder head mating surface.
2. Apply a light coat of engine oil to the threads and the underside of the bolt head of bolts #1 thru #8.
3. Apply sealing compound P/N 1052080 to threads of bolts #9 and #10.
4. Install all cylinder head bolts and torque on 25 N-m (18 ft.lbs.) in specified sequence (see illustration).
5. Repeat the sequence bringing torque to 30 N-m (22 ft. lbs.) on all bolts except #9. Torque #9 to 40 N-m (30 ft.lbs.).
6. Repeating the sequence, rotate all bolts except #9, 120 degrees (two (2) flats).
7. #9 bolt should be rotated 90 degrees (1/4 turn).
Use applicable labor time and operation number for cylinder head gasket replacement.