What is the procedure for tightening TTY head bolts on GM 3.8L engines?
The AERA Technical Committee offers the following information regarding cylinder head installation for 1995-2002 GM 3.8L VIN K and 1 engines. AERA TB 1952 should be discarded. According to AERA, other published service information has been incomplete and this is the most up to date information.
It is important to remember that the cylinder head bolts used for these engines should be replaced any time the heads are re-installed. Failure to replace the bolts during head installation may reduce clamping force and head gasket service life.
To install new head bolts on these engines, use a torque angle tool and:
- Thoroughly clean the threads in the block using a 7/16-14 tap.
- Install the head gasket with the arrow pointing to the front of the engine.
- Install the new cylinder head bolts dry.
Notice: This bolt is designed to permanently stretch when tightened. The correct part number fastener must be used to replace this type of fastener. If the correct bolt is not used, the parts will not be tightened correctly and the engine may be damaged.
Step 1: Tighten all bolts in sequence (see Figure 1) to 35-37 ft.lbs. (49-50 Nm).
Step 2: Rotate each bolt 130