Engine

The 3.7L (4V) is a (TiVct) V6 engine with the following features:

• Dual overhead camshafts
• Four valves per cylinder
• Sequential Multi-Port Fuel Injection (SFI)
• A composite lower intake manifold and upper intake manifold
• Aluminum cylinder heads
• An aluminum, 60-degree V-cylinder block
• Twin independent Variable Camshaft Timing (VCT) system
• The electronic ignition system with 6 ignition coil on plugs
• 305 horsepower

Engine Identification

For quick identification, refer to the safety certification decal.

• The decal is located on the LH front door lock face panel.

Engine Code Information Label

The engine code information label, located on the front side of the valve cover, contains the following:

Engine Cylinder Identification

Exhaust Emission Control System

Operation and required maintenance of the exhaust emission control devices used on this engine is covered in the Powertrain Control/Emissions Diagnosis (PC/ED) manual.

Induction System

The SFI provides the fuel/air mixture needed for combustion in the cylinders. The 6 solenoid-operated fuel injectors:

• are mounted between the fuel rail and the intake manifold.
• meter fuel into the air intake stream in accordance with engine demand.
• are positioned so that their tips direct fuel just ahead of the engine intake valves.

Valve Train

The valve train uses Direct Acting Mechanical Buckets (DAMB). The camshaft lobes are positioned directly above mechanical buckets which are positioned on top of the valves.

Twin IndependentVariable Camshaft Timing (VCT) System

The twin independent VCT system allows variable control of intake valve closing which optimizes combustion at full load providing improved power and low speed torque (broadening the torque curve) which enables variable valve overlap which provides better fuel economy and emissions and provides optimized cold start operation with improved exhaust emissions.

PCV System

All engines are equipped with a closed-type PCV system recycling the crankcase vapors to the upper intake manifold.

Lubrication System

The engine lubrication system is of the force-feed type in which oil is supplied under full pressure to the crankshaft, connecting rod bearings, piston cooling jets, timing chain tensioners and VCT solenoids. The flow of oil to the valve tappets and valve train is controlled by a restricting orifice located in the cylinder head, valve train oil feed tubes. Die cast aluminum deep sump oil pan for 10,000 mile oil change intervals.

Oil Pump

The lubrication system is designed to provide optimum oil flow to critical components of the engine through its entire operating range.

The heart of the system is a positive displacement internal gear oil pump.

Generically, this design is known as a gerotor pump, which operates as follows:

• The oil pump is mounted on the front face of the cylinder block.
• The inner rotor is piloted on the crankshaft post and is driven through flats on the crankshaft.
• System pressure is limited by an integral, internally-vented relief valve which directs the bypassed oil back to the inlet side of the oil pump.
• Oil pump displacement has been selected to provide adequate volume to ensure correct oil pressure both at hot idle and maximum speed.
• The relief valve calibration protects the system from excessive pressure during high-viscosity conditions.
• The relief valve is designed to provide adequate connecting rod bearing lubrication under high-temperature and high-speed conditions.

Engine Oil Flow Illustration

Engine Assembly

Dual Mass Flywheel

NOTE: The dual mass flywheel normally has up to a total of 14 degrees (6.5 ring gear teeth) maximum rotational freeplay between the primary (bolted to crankshaft) and the secondary mass (clutch disc face).

A dual-mass flywheel is essentially two flywheels in one that provides spring cushioning to dampen torsional crankshaft vibrations and shock loading when the clutch is engaged. The two-piece assembly has a front "primary" mass and a rear "secondary" mass. The primary mass bolts to the crankshaft like an ordinary solid flywheel, and includes the ring gear for the starter. The clutch is bolted to the secondary mass, which is separate from the primary mass, but attached to it with a series of coil springs mounted sideways between the two. The springs allow just enough movement between the masses to transmit less engine vibration to the driveline, reduce some of the jarring and stress on the transmission and the remainder of the drivetrain when the clutch is engaged. The cushioning effect also reduces shock loading on the transmission for longer gear life and less noise.

Cooling System

The engine cooling system includes the following:

• Radiator
• Coolant pump
• Electric fan assembly(s)
• Degas bottle (aids in maintaining the correct volume of engine coolant)
• Coolant thermostat
• Coolant hoses

The channel cover plate is located under the engine front cover mounted to the block. It contains a timing chain idler and press and place gaskets separating engine coolant and engine oil. If oil or coolant is leaking from the weep hole, then a gasket has failed and must be replaced. A weep hole is provided on the front left side of the engine behind the generator. This weep hole create a reservoir for normal coolant seepage and evaporation. Every channel cover plate will have some leakage past the dynamic mechanical seal. Dampness and crusting around the weep hole is acceptable and an expected result of normal engine operation. Coolant spray or leakage amounts great enough to puddle should be addressed.