Hummer H1 Service Manual page 81

_____________________________________________________________________
2-44 Engine
EXHAUST MANIFOLDS
Removal
1. Remove consoles and engine cover for access to turbo-
charger inlet pipes. For information regarding inlet pipes,
refer to Section 3.
2. Loosen flange clamps that secure left inlet pipe to exhaust
manifold and turbocharger. On right side, loosen flange
clamp and remove nuts that attach inlet pipe to exhaust
manifold. Then disconnect pipe and move aside for
working clearance.
3. Remove heat shield attaching nuts/bolts and remove
shield, if equipped.
4. Disconnect glow plug wires.
5. Remove manifold attaching bolts and remove manifold
(Figure 2-50).
6. Remove and discard manifold gasket.
DIESEL VACUUM PUMP SERVICE
A vacuum pump is used on all diesel models.
The pump is located on the passenger side of the engine just
below the alternator (Figure 2-51).
This supplies vacuum for wastegate actuator operation on
turbo models and for A/C and heater operation on diesel mod-
els. The pump is belt driven and has a removable pulley.
The pump is tested with a standard vacuum gauge. Output
should be a minimum of 20-21 inches vacuum.
Pump removal only requires loosening the serpentine belt, dis-
connecting the vacuum output hose, and removing the pump
attaching bolts.
PASSENGER
SIDE
MANIFOLD
Figure 2-50: Exhaust Manifold Attachment
7. Clean old gasket material off cylinder head and manifold
with scraper and wire brush.
Installation
1. Place new gasket on manifold, position manifold on cylin-
der head, and install 1-2 bolts to hold manifold in place.
2. Install heat shield and remaining manifold bolts. Tighten
bolts to 18-25 lb-ft (24-34 N•m) torque.
3. Connect glow plug wires.
4. Install flange clamps and turbocharger inlet pipes. If
installing right side manifold, tighten inlet pipe-to-
manifold attaching nuts to 37 lb-ft (50 N•m) torque.
Tighten exhaust flange clamps to 71 lb-in (8 N•m) torque.
5. Install turbocharger heat shields.
6. Install engine cover and consoles.
ALTERNATOR
VACUUM
PUMP
Figure 2-51: Vacuum Pump Location
DRIVER
SIDE
MANIFOLD
PUMP
SERPENTINE
PULLEY
BELT
®