Engine
EngineWARNING: Do not operate the engine with the hood open until the fan blade has been first examined for possible cracks and separation.
The 3.9L (238 CID) is a V 8 engine with the following features:
^ Dual overhead camshafts
^ 4 valves per cylinder
^ Sequential Multiport Fuel Injection (SFI)
^ Aluminum cylinder heads
^ Cast aluminum, 90 degree V cylinder block
^ Individually chain driven camshafts with a hydraulic timing chain tensioner on each timing chain
^ Electronic ignition system with 8 ignition coils
Identification
For quick identification refer to the safety certification decal.
^ The decal is located on the LH front door lock face panel.
^ Find the engine code (letter or number) on the decal, then refer to the Engine Identification Chart to determine engine type and size.
^ The symbol code on the identification tag identifies each engine for determining parts usage; for example, engine displacement in liters or cubic inch displacement and model year.
Engine Code Information
The engine code information label is located on the valve cover. 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.
Exhaust Emission Control System
Refer to Computers and Control Systems.
Induction System
The air/fuel mixture is provided by the Multiport Fuel Injection (MFI) system.
Fuel is:
^ supplied from the fuel tank by the fuel pump.
^ regulated by the fuel pressure sensor.
^ delivered to the injector supply manifold.
A dual damper has been added to reduce pressure fluctuations caused by the fuel injectors.
Crankshaft
The crankshaft is supported on the bottom of the cylinder block by 5 steel backed, over plated, aluminum crankshaft main bearings.
To provide smooth engine operation, the piston crank pins are positioned to provide a power impulse every 90 degrees of crankshaft rotation. The spacing provides smooth and quiet operation.
Camshafts
The camshafts:
^ are arranged in pairs, one each (intake and exhaust) on each cylinder head.
^ are synchronized through a secondary timing chain.
^ depress the direct acting mechanical tappets to actuate the valves.
Valve Train
The valves are actuated by a direct acting mechanical bucket and shim. The direct acting mechanical tappets and shims:
^ provide lash adjustment through a shim selected by thickness.
^ ride on the camshaft lobes.
Crankcase Ventilation System
The engine is equipped with a 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 main bearings.
^ crankshaft thrust main bearing.
^ connecting rod bearings.
^ oil galleys.
Oil Pump
The rotary spur oil pump develops the oil pressure.
^ The oil pump is bolted to the front of the cylinder block.
^ The oil pump is rotated by the crankshaft.
^ A full flow oil filter is externally mounted on the upper sump.
If the filter element becomes blocked, a spring loaded bypass valve opens to allow uninterrupted flow of oil to the engine.
Engine Cooling System
The engine is liquid cooled:
^ by a centrifugal coolant pump driven by the drive belt.
^ a thermostat is used to restrict coolant flow until the engine reaches normal operating temperature.
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:
^ Coolant pump
^ A/C compressor
^ Generator
^ Drive belt tensioner
^ Drive belt idler pulley
^ Crankshaft pulley
^ Power steering pump