Hummer H3. Manual — part 311

Fig. 112: View Of Cylinder Head Bolts
Courtesy of GENERAL MOTORS CORP.

5. Install NEW cylinder head bolts.

NOTE:

This component uses torque-to-yield bolts. When servicing this
component do not reuse the bolts, New torque-to-yield bolts
must be installed. Reusing used torque-to-yield bolts will not
provide proper bolt torque and clamp load. Failure to install
NEW torque-to-yield bolts may lead to engine damage.

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3

Fig. 113: Installing Cylinder Head Bolts
Courtesy of GENERAL MOTORS CORP.

6. Tighten the NEW cylinder head bolts in the following sequence:

Tighten:

1. Tighten the cylinder head bolts (1-12) in sequence to 30 N.m (22 lb ft).

Use the J 45059 to rotate the cylinder head bolts (1-12) in sequence an additional 155
degrees. See Special Tools.

NOTE:

Refer to Fastener Notice .

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3

2. Tighten the (2 Short) end bolts (14-15) to 7 N.m (62 lb in).

Use the J 45059 to rotate the short cylinder head end bolts (14-15) an additional 60
degrees. See Special Tools.

3. Tighten the (1 Long) end bolt (13) to 7 N.m (62 lb in).

Use the J 45059 to rotate the long cylinder head end bolt (13) an additional 120
degrees. See Special Tools.

Fig. 114: Installing Camshafts
Courtesy of GENERAL MOTORS CORP.

CAUTION: The camshaft holding tools must be installed on the

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3

7. Install the camshafts with the flats up using J 44221 . See Special Tools. Refer to

Camshaft Installation.

8. Ensure that the camshaft position actuator is in the fully advanced position. Refer to

Camshaft Position Actuator Diagnosis.

9. Install the exhaust camshaft actuator/sprocket and chain onto the exhaust camshaft. Use the

paint marks as an alignment guide.

10. Install the intake camshaft sprocket and chain onto the intake camshaft. Use paint marks as

camshafts to prevent camshaft rotation. When performing
service to the valve train and/or timing components, valve
spring pressure can cause the camshafts to rotate
unexpectedly and can cause personal injury.

IMPORTANT: Before installing the camshafts, refer to Camshafts Cleaning

and Inspection.

NOTE:

Tension must be always kept on the intake side of the timing
chain to properly keep the engine in time. If the chain is loose
the timing will be off, which may cause internal engine damage
or set DTC P0017.

NOTE:

The exhaust camshaft actuator must be fully advanced during
installation. Engine damage may occur if the camshaft actuator
is not fully advanced.

IMPORTANT: To aid in aligning the actuator to the camshaft, use a 25 mm

(1 in) open end wrench on the hex of the camshaft to rotate.
This will ensure the alignment pin is properly engaged with
the camshaft and hand tighten the new exhaust camshaft
sprocket bolt.

IMPORTANT: To aid in aligning the intake sprocket to the camshaft, use a

25 mm (1 in) open end wrench on the hex of the camshaft to
rotate. This will ensure the alignment pin is properly
engaged with the camshaft and hand tighten the new intake
camshaft sprocket bolt.

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3