Overhaul - 3.8L Engine: Overview Chrysler Pacifica CS

Scheme 203

The 3.8 Liter (231 cu. in.) engine is 60° V-6 engines with cast iron cylinder blocks and aluminum cylinder heads. (Scheme 203) The engine uses a single, block mounted camshaft, roller lifters with pushrods to actuate the valves and either cracked cap, or standard cap, forged connecting rods. The engine does not have provisions for a free wheeling valve train.

The firing order is 1-2-3-4-5-6. The cylinders are numbered from the front of the engine to the rear. The front cylinder bank is numbered 2, 4, and 6. The rear cylinder bank is numbered 1, 3, and 5.

Scheme 204

The engine identification number is located on the rear of the cylinder block just below the cylinder head. (Scheme 204)

ENGINE DIAGNOSIS - INTRODUCTION

Engine diagnosis is helpful in determining the causes of malfunctions not detected and remedied by routine maintenance.

These malfunctions may be classified as either mechanical (e.g, a strange noise), or performance (e.g, engine idles rough and stalls).

Refer to DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - PERFORMANCE and ENGINE DIAGNOSIS - MECHANICAL diagnostic charts, for possible causes and corrections of malfunctions.

For fuel system diagnosis, refer to FUEL SYSTEM .

Additional tests and diagnostic procedures may be necessary for specific engine malfunctions that cannot be isolated with the Service Diagnosis charts. Information concerning additional tests and diagnosis is provided within the following

1. Cylinder Compression Pressure Test
2. Cylinder Combustion Pressure Leakage Test
3. Engine Cylinder Head Gasket Failure Diagnosis
4. Intake Manifold Leakage Diagnosis
5. Hydraulic Lash Adjuster Noise Diagnosis
6. Engine Oil Leak Inspection

DESCRIPTION

The valves have chrome plated valve stems with four-bead lock grooves. The valve stem seals are made of Viton rubber.

OPERATION

The two valves per cylinder are opened using roller hydraulic lifters, push rods, and rocker arms.

Scheme 205

The intake and exhaust valves and seats are machined to specific angles. (Scheme 205)

Scheme 206

1. Inspect the remaining margin after the valves are refaced. (Scheme 206) (Refer to «STANDARD PROCEDURE - REFACING VALVES AND VALVE SEATS»(ref-245455-S09720193972006110200000) )

Scheme 207

Scheme 208

Scheme 209

1. When refacing valve seats, it is important that the correct size valve guide pilot be used for reseating stones. A true and complete surface must be obtained. 1 - DIAL INDICATOR
2. Measure the concentricity of valve seat using dial indicator. (Scheme 208) Total runout should not exceed 0.051 mm (0.002 in.) total indicator reading.
3. Inspect the valve seat using Prussian blue to determine where the valve contacts the seat. To do this, coat valve seat LIGHTLY with Prussian blue then set valve in place. Rotate the valve with light pressure. If the blue is transferred to the center of valve face, contact is satisfactory. If the blue is transferred to top edge of valve face, lower valve seat with a 15 degree stone. If the blue is transferred to the bottom edge of valve face raise valve seat with a 65 degrees stone. NOTE: Valve seats which are worn or burned can be reworked, provided that correct angle and seat width are maintained. Otherwise cylinder head must be replaced.
4. When seat is properly positioned the width of intake and exhaust seats should be 1.50-2.00 mm (0.059-0.078 in.). (Scheme 205) 1 - SPRING RETAINER 2 - VALVE INSTALLED HEIGHT* - 48.1-49.7 mm (1.89-1.95 in.) 3 - CYINDER HEAD SURFACE 4 - SPRING INSTALLED HEIGHT* - 41.1-42.7 mm (1.61-1.68 in.) *(MEASURED FROM TOP OF SPRING SEAT)
5. After grinding the valve seats or faces, install the valve in cylinder head and check valve installed height by measuring from valve tip to spring seat. (Scheme 209) Remove valve from cylinder head and grind valve tip until within specifications. Check valve tip for scoring. The tip chamfer should be reground (if necessary) to prevent seal damage when the valve is installed.
6. Check the valve spring installed height after refacing the valve and seat. (Scheme 209)

Scheme 210

Scheme 211

1. With cylinder head removed, compress valve springs using Valve Spring Compressor Tool C-3422-D with adapter 8464. (Scheme 210) 1 - VALVE LOCKS 5 - SPRING SEATS 2 - RETAINERS 6 - CYLINDER HEAD 3 - VALVE SPRINGS 7 - VALVE - EXHAUST 4 - VALVE STEM SEALS 8 - VALVE - INTAKE
2. Remove valve retaining locks. (Scheme 211)
3. Slowly release valve spring compressor. Remove valve spring retainer, valve spring, and valve stem seal.
4. Before removing valves, remove any burrs from valve stem lock grooves to prevent damage to the valve guides. Identify valves to insure installation in original location.

The valve spring returns the valve against its seat for a positive seal of the combustion chamber.

DESCRIPTION - ROCKER ARMS

The rocker arms are installed on the rocker arm shaft. The rocker arms and shaft assembly is attached to the cylinder head with seven billeted bolts and retainers. The rocker arms are made of stamped steel.

OPERATION - ROCKER ARMS

The rocker arm pivots are on the rocker shaft. Rocker arms are used to translate up and down motions provided by the camshaft, hydraulic roller lifter, and pushrod on one end, into a down and up motions on the valve stem on the opposing end.

OPERATION - PUSHRODS

The pushrod is a solid link between the hydraulic roller lifter and the rocker arm. Also, the pushrod supplies engine oil from the hydraulic lifter to the rocker arm.

Scheme 212

1. Remove the cylinder head cover(s). (Refer to «CYLINDER HEAD COVER(S)»(ref-245455-S28149962872006110200000) ) NOTE: Rocker arm shaft bolts are captured to the shaft.
2. Loosen the rocker shaft bolts. (Scheme 212), rotating one turn each, until all valve spring pressure is relieved.
3. Remove the rocker arms and shaft assembly. (Scheme 212)
4. For rocker arm disassembly procedures, «(Refer to ENGINE/CYLINDER HEAD/ROCKER ARMS - DISASSEMBLY)»(ref-245455-S30883306922006110200000).

Scheme 213

Scheme 214

1. Remove the rocker arm retainer and bolt by performing the following procedure: Using adjustable pliers, grip the edges of the retainer. (Scheme 213) Apply an upward force with a slight rocking motion until the retainer disengages from shaft. (Scheme 213) 1 - BOLT (ROCKER SHAFT OIL FEED - LONGER LENGTH) 5 - ROCKER ARM - EXHAUST 2 - SHAFT RETAINER/SPACER - 21.5 mm (0.84 in.) 6 - WASHER 3 -SHAFT RETAINER/SPACER - 37.5 mm (1.47 in.) 7 - ROCKER ARM - INTAKE (LARGER OFFSET) 4 - SHAFT RETAINER/SPACER - 40.9 mm (1.61 in.) 8 - ROCKER ARMS LUBRICATION FEED HOLE (POSITION UPWARD & TOWARD VALVE SPRING)
2. Remove rocker arms. (Scheme 214) Identify the component locations for reassembly in original locations.

The valve stem seals are made of Viton rubber. The seals are positioned over the valve stem and seated on the valve guide. see scheme 84

The cylinder block is made of cast iron and is a deep skirt design.

Scheme 215

1. Used carefully, the cylinder bore resizing hone, recommended tool C-823 or equivalent, equipped with 220 grit stones, is the best tool for this honing procedure. In addition to deglazing, it will reduce taper and out-of-round as well as removing light scuffing, scoring or scratches. Usually a few strokes will clean up a bore and maintain the required limits.
2. Deglazing of the cylinder walls may be done using a cylinder surfacing hone, recommended tool C-3501 or equivalent, equipped with 280 grit stones, if the cylinder bore is straight and round. 20-60 strokes depending on the bore condition, will be sufficient to provide a satisfactory surface. Use a light honing oil. Do not use engine or transmission oil, mineral spirits or kerosene. Inspect cylinder walls after each 20 strokes.
3. Honing should be done by moving the hone up and down fast enough to get a cross-hatch pattern. When hone marks intersect at 40-60 degrees, the cross hatch angle is most satisfactory for proper seating of rings. (Scheme 215)
4. A controlled hone motor speed between 200-300 RPM is necessary to obtain the proper cross-hatch angle. The number of up and down strokes per minute can be regulated to get the desired 40-60 degree angle. Faster up and down strokes increase the cross-hatch angle.
5. After honing, it is necessary that the block be cleaned again to remove all traces of abrasive.

The camshaft is driven by the crankshaft through a timing chain and sprockets. The camshaft has precisely machined (egg-shaped) lobes to provide accurate valve timing and duration.

Scheme 216

1. Remove the engine assembly from vehicle (Refer to «REMOVAL - ENGINE ASSEMBLY»(ref-245455-S27282772212006110200000) ).
2. Remove the cylinder heads (Refer to «CYLINDER HEAD»(ref-245455-S11415369272006110200000) ).
3. Remove the timing chain and camshaft sprocket (Refer to «TIMING CHAIN AND SPROCKETS»(ref-245455-S16803643932006110200000) ).
4. Remove the hydraulic lifters «(Refer to ENGINE/ENGINE BLOCK/HYDRAULIC LIFTERS (CAM IN BLOCK)»(ref-245455-S03365153252006110200000) ). Identify each tappet for reinstallation in original location.
5. Remove camshaft thrust plate. (Scheme 216) NOTE: Slowly remove the camshaft from the engine taking precautions not to damage the camshaft bearings.
6. Install a long bolt into front of camshaft to facilitate removal of the camshaft.
7. Carefully remove the camshaft. (Scheme 216)

Note. The camshaft bearings are serviced with the engine block.

Scheme 217

1. Check the cam lobes and bearing surfaces for abnormal wear and damage. (Scheme 217) Replace camshaft as required. NOTE: If camshaft is replaced due to lobe wear or damage, always replace the lifters.
2. Measure the lobe actual wear (unworn area - wear zone = actual wear). (Scheme 217)and replace camshaft if out of limit. Standard value is 0.0254 mm (0.001 in.), wear limit is 0.254 mm (0.010 in.).

Scheme 218

1. Lubricate camshaft lobes and camshaft bearing journals with engine oil. (Scheme 218)
2. Install a long bolt into the camshaft to assist in the installation of the camshaft. (Scheme 218)
3. Carefully install the camshaft in engine block. (Scheme 218)
4. Install camshaft thrust plate and bolts. (Scheme 218) Tighten to 12 N.m (105 in. lbs.) torque.
5. Measure camshaft end play. (Refer to «SPECIFICATIONS»(ref-245455-S08864132092006110200000) ) If not within specifications, replace thrust plate.
6. Install the timing chain and sprockets. (Refer to «TIMING CHAIN AND SPROCKETS»(ref-245455-S16803643932006110200000) ) NOTE: When camshaft is replaced, all of the hydraulic lifters must be replaced.
7. Install the hydraulic lifters with lubrication whole in the upward position «(Refer to ENGINE/ENGINE BLOCK/HYDRAULIC LIFTERS (CAM IN BLOCK)»(ref-245455-S14894403622006110200000) ).
8. Install the timing chain cover. (Refer to «TIMING CHAIN COVER»(ref-245455-S23497034262006110200000) )
9. Install the cylinder heads. (Refer to «CYLINDER HEAD»(ref-245455-S11415369272006110200000) )
10. Install the cylinder head covers. (Refer to «CYLINDER HEAD COVER(S)»(ref-245455-S28149962872006110200000) ).
11. Install the lower and upper intake manifolds. (Refer to «INTAKE MANIFOLD - UPPER»(ref-245455-S32765950852006110200000) and «INTAKE MANIFOLD - LOWER»(ref-245455-S24570546002006110200000) )
12. Install the engine assembly. (Refer to «INSTALLATION - ENGINE ASSEMBLY»(ref-245455-S19019767862006110200000) )

Note. The 3.8L may have any combination of forged or cracked cap connecting rods. The cracked cap design is easily identified by the connecting rod cap bolts rather than the traditional forged connecting rod cap nuts. The cracked cap design also has a different tightening procedure and specification. The connecting rod caps must be paint marked or scribed to identify the accompanying connecting rod. All connecting rod caps ARE NOT inner changeable between connecting rods.

The pistons are made of cast aluminum alloy and are a strutless, short skirt design. The connecting rods have either the standard forged caps or forged cracked cap design. Both the cracked cap and forged cap connecting rod designs are interchangeable and may be found in any combination when mounted to the crankshaft. The difference between the two different rod caps, aside from design, is the tightening procedure and specification. The piston rings consist of two compression rings and a three piece oil ring. Piston pins connect the piston to the forged steel connecting rods. The piston pins are a press fit into the connecting rod small bore. The piston, pin and connecting rod are serviced as an assembly.

Scheme 219

The bearing caps are not interchangeable or reversible, and should be marked at removal to ensure correct reassembly. Forged bearing caps stay with forged rods, cracked bearing caps stay with the forged cracked rod. The bearing shells must be installed with the tangs inserted into the machined grooves in the rods and caps. Install cap with the tangs on the same side as the rod. For connecting rod bearing fitting (Refer to STANDARD PROCEDURE - MEASURING CONNECTING ROD BEARING CLEARANCE ). Fit all connecting rods on one bank until complete.

Note. The connecting rod cap bolts should be examined before reuse. Bolt stretch can be checked by holding a scale or straight edge against the threads. If all the threads do not contact the scale the bolt must be replaced. (Scheme 219)

Scheme 220

1. Before installing the nuts or the bolts the threads should be oiled with engine oil.
2. Install nuts or bolts finger tight then alternately torque each nut or bolt to assemble the cap properly.
3. Tighten the nuts to 54 N.m PLUS 1/4 turn (40 ft. lbs. PLUS 1/4 turn).
4. Tighten the cracked cap bolts to 28 N.m PLUS 90 degrees (20 ft.lbs.) plus 90 degrees.
5. Using a feeler gauge, check connecting rod side clearance. (Scheme 220) (Refer to «SPECIFICATIONS»(ref-245455-S08864132092006110200000) ).

Scheme 221

Note. Pistons and connecting rods are machined to tight weight tolerances and need not be sorted in any way.

The piston and cylinder wall must be clean and dry. Piston diameter should be measured 90 degrees to piston pin at size location (Scheme 221)

Scheme 222

Cylinder bores should be measured halfway down the cylinder bore and transverse to the engine crankshaft center line (Scheme 222) (Refer to SPECIFICATIONS ). Pistons and cylinder bores should be measured at normal room temperature, 21°C (70°F).

The engine mounting system consist of four mounts; right and a left side support the powertrain, and a front and a rear mount control powertrain torque. The right side mount is a hydro-type, all others are of molded rubber material.

Scheme 223

1. Remove air cleaner housing.
2. Remove the load on the upper engine mount by carefully supporting the engine assembly with a floor jack.
3. Remove the bolts attaching the engine mount to the frame rail. (Scheme 223)
4. Remove the bolts attaching the engine mount to the engine bracket. (Scheme 223)
5. Remove the upper engine mount. (Scheme 223)

The lubrication system is a full flow filtration pressure feed type. The oil pump is mounted in the timing chain cover and is driven by the crankshaft

Scheme 224

Oil from the oil pan is pumped by a internal gear type oil pump directly coupled to the crankshaft. The pressure is regulated by a relief valve located in the timing chain cover. The oil is pumped through an oil filter and feeds a main oil gallery. This oil gallery feeds oil under pressure to the main and rod bearings, camshaft bearings. Passages in the cylinder block feed oil to the hydraulic lifters and rocker shaft brackets which feeds the rocker arm pivots. (Scheme 224)

Engine oil travels from the oil filter and into the oil cooler. Engine oil then exits the cooler into the main gallery. Engine coolant flows into the cooler from the heater return tube and exits into the water pump inlet.

Scheme 225

Scheme 226

1. Drain cooling system «(Refer to COOLING - STANDARD PROCEDURE - COOLING SYSTEM DRAINING)»(ref-245448-S20805593812006110200000).
2. Disconnect oil cooler inlet and outlet hoses. (Scheme 225) 1 - OIL FILTER ADAPTER 2 - CONNECTOR 3 - ENGINE OIL COOLER 4 - OIL COOLER ATTACHMENT FITTING 5 - OIL FILTER
3. Remove oil filter.
4. Remove oil cooler attachment fitting. (Scheme 226)
5. Remove oil cooler.

The engine oil pressure switch is located on the lower left front side of the engine. It screws into the oil filter adapter. The normally closed switch provides an input through a single wire to the low pressure indicator light on the instrument cluster.

The oil pressure switch provides a ground for the instrument cluster low oil pressure indicator light. The switch receives oil pressure input from the engine main oil gallery. When engine oil pressure is greater than 27.5 Kpa (4 psi), the switch contacts open, providing a open circuit to the low pressure indicator light. For wiring circuits and diagnostic information, (Refer to POWERTRAIN DIAGNOSTIC PROCEDURES and SYSTEM WIRING DIAGRAMS ).

Scheme 227

1. Raise vehicle on hoist.
2. Disconnect electrical connector from switch.
3. Remove oil pressure switch. (Scheme 227)

The oil pump is located in the timing chain cover. It is driven by the crankshaft.

The intake system is made up of an upper and lower intake manifold. The upper intake manifold is made of a composite material for the 3.8L engine. The lower intake manifold also provides coolant crossover between cylinder heads and houses the coolant thermostat.

The intake manifold utilizes a compact design with very low restriction and outstanding flow balance. This design allows the engine to perform with a wide torque curve while increasing higher rpm horsepower.

If, for some reason, the molded-in vacuum ports break, the composite manifold can be salvaged. The vacuum ports are designed to break at the shoulder, if overloaded. Additional material in the shoulder area provides sufficient stock to repair. For more information and procedure, (Refer to ENGINE/MANIFOLDS/INTAKE MANIFOLD - STANDARD PROCEDURE) . Also, if the special screws that attach the MAP sensor, power steering reservoir, throttle cable bracket, and the EGR tube become stripped, an oversized screw is available to repair the stripped-out condition. For more information and procedure, (Refer to ENGINE/MANIFOLDS/INTAKE MANIFOLD - STANDARD PROCEDURE)