Hummer H1 (2006+). Instruction - page 24
2-2
Engine
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ENGINE DESCRIPTION
A turbocharged diesel engine is used in the HUMMER H1 vehicles. It is a liquid cooled, four-stroke, 90° – V8 engine with a dis-
placement of 6.6L (402 cu. in.) (Figure 2-1). The engine is manufactured by Duramax Inc. (GM / Isuzu).
Figure 2-1: 6.6L Turbo Diesel Engine
Engine Components
The engine block is grey iron and the cylinder heads are aluminum. Turbo engines are equipped with a three-piece aluminum in-
take manifold and cast iron exhaust manifolds.
The oil cooling system for turbo diesel pistons provides for oil spray onto the underside of the piston crown. This is accomplished
by additional oil feed orifice tubes and galleries in the block. Oil spray occurs when the piston is approaching bottom dead center
on the intake and power strokes. The extra oil pressure and volume needed for piston cooling is provided by a high output oil
pump. The pump has a working pressure of 55 to 60 psi at 3250 RPM. Oil feed for piston spray is through galleries and oil tubes lo-
cated in the main bearing saddles and webs.
The crankshaft is supported by five insert style main bearings. The camshaft is also supported by five bearings; plain type bearings
are used.
The engine is equipped with three ring aluminum pistons. Connecting rods are forged steel. The pistons are attached to the rods
with hardened steel piston pins. Each piston pin is retained by two snap rings; one at each end of the pin. The pin is a floating fit in
the rod and piston.
A gear driven camshaft operates the overhead valve train. Roller lifters and tubular push rods actuate the rocker arms. The arms are
mounted on shafts bolted to each cylinder head.
The cylinder heads are equipped with glow plugs for each cylinder and a prechamber for each combustion chamber. One plug and
one prechamber are used in each combustion chamber. The glow plugs heat the air entering the prechamber. This aids the combus-
tion process and improves cold weather starting and operation. The glow plugs are activated only when ambient temperatures fall
below a pre-set value. On the turbo diesel engine the glow plug relay is mounted on the intake manifold and is controlled by the
ECM.
The turbocharged diesel engine is equipped with an IHI turbocharger. Vanes in the turbine housing control the boost. The position
of the vanes is variable and controlled by a vain position solenoid based on information sent to the ECM by the boost sensor. The
vane position is monitored by the vane position sensor. This allows a proportionate increase in fuel injected into the cylinders. The
result is a much denser cylinder charge and greater power output.
The turbocharger turbine and compressor impellers are the mechanisms that pump additional air into the combustion chambers.
The impeller wheels are operated by the high speed gas flow through the engine exhaust system.
Engine lubrication is through a conventional mechanical pump located at the rear of the crankcase. The pump is shaft driven by the
oil pump drive unit which in turn, is driven off the camshaft. The 6.6L diesel is equipped with a high pressure fuel injection system.
The system consists of an electric fuel supply pump, an injection pump, a separate injector nozzle for each cylinder, and the neces-
sary injector feed lines.
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The fuel injection pump at the front of the engine valley uses a fuel rail pressure regulator (which is actually a pressure control
valve that is controlled by the ECM). The assembly consists of a supply gear pump at the end of the unit. The much larger section
is the actual high pressure feed pump. The pump generates peak fuel pressure of approximately 23,000 psi. 5,000 to 6,000 psi is the
typical pressure at idle. The pump is engine driven by the camshaft gear.
The fuel passes through the base plate of the Fuel Injection Control Module (FICM) to cool the module. This high voltage unit di-
rectly pulses the fuel injectors in the high pressure system when commanded by the ECM.
The fuel cooler on the return line increases fuel handling efficiency. The cooler is mounted on the cool pack.
ENGINE IDENTIFICATION
The diesel engine I.D. decal is located on the back face of the driver side lower rocker arm cover (Figure 2-2).
The decal provides the engine assembly/serial number and a bar code.
Figure 2-2: Diesel Engine I.D. Tag Location
Service Tools
The special service tools described in this section are available through the dealer tool program.
Specifications
Engine specifications for overhaul, adjustment, inspection and torque requirements are provided at the end of this section.
LUBRICANTS/SEALANTS/COOLANT
Engine Oil
Recommended engine oil for the diesel engines used in HUMMER H1 vehicles, is API classification CG-42-3. Synthetic oils are
equally acceptable.
ENGINE SERIAL NUMBER
BAR CODE DECAL
2-4
Engine
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Oil viscosity recommendations are: (Figure 2-3)
SAEþ15W-40 As shown in the viscosity chart, SAEþ15W-40 is best for your vehicle. However, you can use SAEþ10W-30 at tem-
peratures above 0°F (-18°C). When it is very cold, below 0°F (-18°C), you should use SAEþ5W-40 to improve cold starting. These
numbers on the oil container show its viscosity or thickness. Do not use other viscosity oils such as SAEþ10W-40 or SAEþ20W-
50.
Figure 2-3: Oil Viscosity Chart
Sealants
Anaerobic, RTV (room temperature vulcanizing) and standard sealants are all used for various repairs.
RTV sealers are used when a non-rigid part is attached to a rigid part (e.g. oil pan to engine block).
Typical RTV sealers would be Permatex High Temp, Ultra Copper, Ultra Black, or Loctite 599.
Anaerobic (gasket eliminator) sealants are used where two rigid parts are being assembled. This type of sealant cures in the ab-
sence of air. Typical anaerobic sealers are Loctite 510 and 518.
Standard type sealers are used primarily as gasket dressing or thread sealants. Typical examples would be Permatex #2, or Perfect
Seal spray sealer.
Thread locking sealants are frequently recommended for fasteners subject to heat and vibration. Recommended products are:
• Loctite 242 for all purpose use
• Loctite “Stud and Bearing Mount” for semi-permanent attachment
Coolant
The cooling system in your vehicle is filled with DEX-COOL® engine coolant. This coolant is designed to remain in your vehicle
for 5þyears or 60,000þmiles, whichever occurs first, if you add only DEX-COOL® extended life coolant.
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A 50/50þmixture of clean, drinkable water and DEX-COOL® coolant will:
• Give freezing protection down to -34°F (-37°C)
• Give boiling protection up to 265°F (129°C)
• Protect against rust and corrosion
• Help keep the proper engine temperature
• Let the warning lights and gages work as they should
CAUTION: Using coolant other than DEX-COOL may cause premature engine, heater core or radiator corrosion. In addition,
the engine coolant may require changing sooner, at 30,000þmiles (50þ000þkm) or 24þmonths, whichever occurs first. Any repairs
would not be covered by your warranty. Always use DEX-COOL (silicate-free) coolant in your vehicle.
What to Use
Use a mixture of one-half clean, drinkable water and one-half DEX-COOL® coolant which won't damage aluminum parts. If you
use this coolant mixture, you don't need to add anything else.
CAUTION: Adding only plain water to your cooling system can be dangerous. Plain water, or some other liquid such as alcohol,
can boil before the proper coolant mixture will. Your vehicle's coolant warning system is set for the proper coolant mixture. With
plain water or the wrong mixture, your engine could get too hot but you would not get the overheat warning. Your engine could
catch fire and you or others could be burned. Use a 50/50 mixture of clean, drinkable water and DEX-COOL® coolant.
CLEANING MATERIALS
Normal parts cleaning solvents can be used for most purposes.
Use brake or contact cleaner, to clean surfaces where anaerobic or RTV sealants will be applied. This type of solvent does not leave
a residue that interferes with sealer cure or adhesion.
Carbon deposits can be emulsified by some spray type gasket removers. Permatex and 3M both have effective products.
Avoid using diesel fuel, gasoline, paint and lacquer thinners or kerosene for parts cleaning purposes. These products can leave an
undesirable residue.
Cylinder and lifter bores should be cleaned with a liquid detergent and warm water mixture after honing or polishing. A bristle
brush or cotton towel can be used to wash the bores until clean and free of oil, dirt, and abrasive grit.
COMPRESSION TEST
1.
Remove the engine ignition fuse under the hood.
2.
Disconnect and remove all the glow plugs.
3.
Thread adapter J
–
26999-20 into the glow plug hole of the first cylinder to be tested. Then attach the compression gauge J
–
26999 to the adapter.
4.
Have a helper crank the engine through six cycles (to generate six compression strokes). Note and record the gauge pressure.
Repeat procedure at the remaining cylinders.
5.
The minimum compression in any one cylinder is 2069þkPa (300þpsi). There should not be more than 345þkPa (50þpsi)
difference between a suspect cylinder and the average compression of all 8þcylinders.
CAUTION: Never inject oil into the diesel engine cylinders for any reason. This could result in piston and rod damage because of
the minimal clearances in a high compression diesel combustion chamber.
FUEL FILTER WARNING LAMP
All HUMMER H1 models are equipped with a fuel filter warning lamp. The lamp is in circuit with a sensor mounted in the filter.
The purpose of the lamp is to alert the driver when water, ice or wax buildup occurs in the filter.
Lamp illumination can be intermittent or continuous depending on the severity of water or wax buildup.
In most cases, continuous illumination of the lamp simply means it is time to drain the filter. However, a continuous lamp plus en-
gine stall or restart problems may indicate a plugged filter or fuel lines. Intermittent illumination of the lamp indicates that water is
accumulating in the filter. In this instance, it is only necessary to drain off the water at the wheel house drain cock.
