General

The 3.0L (4V) (182 CID) is a 60-degree V-6 engine with Dual Overhead Camshafts (DOHC), four valves per cylinder and Sequential Multiport Fuel Injection (SFI). The engine has:
- an aluminum upper intake manifold.
- a lower intake manifold.
- aluminum cylinder heads.
- a cast aluminum upper cylinder block.
The ignition system is electronic (distributorless) with a single ignition coil located above each spark plug. This high-energy ignition system is required for fast-burn combustion.
A unique intake air system utilizes two separate plenums, one for each side of the engine. The plenums can be connected through the operation of a special Intake Manifold Tuning (IMT) valve to improve upper rpm power.

Identification
For quick identification refer to the safety certification decal:
- The decal is located on the LH front door lock face.
- An engine identification label is also attached to the engine.
- The symbol code on the identification tag identifies each engine for determining parts usage; for instance, engine displacement in liters or cubic inch displacement and model year.

Engine Code Information
The engine code information label is located on the front fender. The label contains, among other information:
- the engine calibration number.
- the engine build date.
- the engine plant code.
- the engine code.

Emission Calibration Label

NOTE: The engine codes and the calibration numbers must be used when making inquiries or ordering parts.

The emission calibration number label is located on the LH side door or LH door post pillar. It identifies:
- the engine calibration number.
- the engine code number.
- the revision level.
These numbers are used to determine if parts are unique to specific engines.

Induction System
The fuel needed for burning in the cylinders is provided by a returnless, Sequential Multiport Fuel Injection (SFI).
Fuel is supplied from the vehicle fuel tank by a high-pressure electric fuel pump mounted in the fuel tank.
- The fuel is filtered and sent to the fuel injection supply manifold.
- Fuel pressure is regulated by modulating pump output based upon readings from the fuel pressure sensor, located on the fuel rail.
- Fuel is metered into the intake air stream in accordance with engine by six solenoid-operated fuel injectors mounted in the lower intake manifolds.
- The six fuel injectors are mounted above the intake valves and connected in series with the fuel pressure regulator.
- These fuel induction systems are mounted on a phenolic resin intake manifold.

Crankshaft
The crankshaft is supported on the bottom of the cylinder block by four steel-backed, over-plated, aluminum crankshaft main bearings.
To provide smooth engine operation, the piston crankpins are positioned to provide a power impulse every 120° of crankshaft rotation. The spacing provides smooth and quiet operation.
Two sprockets and timing chains connect the crankshaft with the camshafts and provide a 2:1 drive ratio.

Camshaft
The camshafts:
- are supported on four bearing inserts.
- thrust loads and end play are limited by a camshaft thrust plate.

Cylinder Head
The spark plug is installed in the center of the fuel/air roof-shaped combustion chamber to ignite the mixture in the combustion chamber. The central location of the spark plug causes the flame front to be evenly spread across the chamber, which also reduces spark knock.

Valve Train
Both camshafts are driven by a shared timing chain, and operate four valves per cylinder by means of a selective shim sitting on the top of a tappet. One spring on each valve is used to close the valve. The adjusting shims in the valve tappets can be changed to correct the valve clearance. These are available in 44 different thicknesses. The shim thickness is ink printed on the back of the shim. Using a special procedure, the camshafts can be lifted without timing chain disassembly to change the shims. A high degree of accuracy is required during adjusting to avoid repeated changing of the shims. The camshaft cams run concentrically on the valve tappets. At engine speeds of about 3,000 rpm this causes the tappets to rotate, and they in turn transfer the rotation to the valves. This valve rotation is required because it produces an even valve seating and prevents the valves from wearing in a certain position which could cause them to leak.

Positive Crankcase Ventilation System
The engine is equipped with a positive, closed-type crankcase ventilation system which recycles the crankcase vapors to the throttle body.

Engine 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 and timing chain tensioners. The flow of oil to the valve tappets and valve train is controlled by a restricting orifice located in the head gaskets.

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 G-rotor pump.
- 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 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 so there is correct oil pressure both at hot idle and maximum speed.
- Relief valve calibration protects the system from excessive pressure during high viscosity conditions, yet is designed to provide adequate connecting rod bearing lubrication under high temperature and high speed conditions.

Engine Cooling System
The engine is liquid-cooled by a centrifugal water pump driven through the front engine accessory drive by the crankshaft.
A water thermostat is used to restrict coolant flow until the engine reaches normal operating temperature.

Oil Pan
The oil pan is cast aluminum and is attached to the cylinder block and transmission.
- The oil pan acts as a reservoir holding lubricating oil that is pumped through the engine by the oil pump after start-up.

Drive Belt System
Accessories mounted on the front of the engine are belt-driven by the crankshaft and an automatically tensioned serpentine drive belt is routed over the following components:
- water pump
- A/C compressor
- generator
- drive belt tensioner
- drive belt idler pulley
- crankshaft pulley
- power steering pump pulley
- cooling fan pump pulley