2.5L V6 Engine: Other Kia Optima I

Intake & Exhaust Valves

Hydraulic valve lash adjusters are used, eliminating need for valve adjustment.

FUEL PRESSURE RELEASE

Open trunk access door and disconnect fuel pump harness connector. Start engine. After engine stalls, turn ignition switch to OFF position. Disconnect negative battery cable. Reconnect fuel pump harness connector.

Note. During removal of wiring and hoses, label each connection for proper reinstallation.

Scheme 27

1. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-121832-S24932646972001091100000). Remove battery, engine cover, and air cleaner. Drain cooling system.
2. Disconnect engine wiring harness connectors, generator harness connectors, oil pressure switch and oil pressure sender. On automatic transaxle models, disconnect oil cooler lines. On manual transmission models, disconnect select control valve.
3. On all models, disconnect radiator hoses from engine connections. Remove radiator assembly.
4. Disconnect spark plug wires and all distributor and ignition coil wires. Disconnect engine ground. Disconnect brake booster vacuum hose.
5. Disconnect main fuel line, and return and vapor hoses from engine. Disconnect heater hoses from engine. Disconnect accelerator cable and cruise control cable.
6. On automatic transaxle models, disconnect shift control cable from transaxle. On manual transmission models, disconnect clutch control cable. On all models, disconnect speedometer cable from transaxle. Remove power steering pump hose.
7. Raise and support vehicle. Remove oil pan shield. Drain transaxle oil.
8. Disconnect front exhaust pipe from exhaust manifold. Suspend exhaust pipe from body.
9. Remove lower control arm ball joint bolts and upper control arm bolt from steering knuckle. Remove drive axles from transaxle. See appropriate article in «FWD AXLE SHAFTS»(ref-122097) article in DRIVE AXLES. Cover all openings to prevent dirt from entering transaxle case.
10. Attach lifting sling to engine, and raise just enough to hold engine weight. Remove front and rear roll stoppers. Disconnect starter connector. Remove engine mount bolts. Remove bolts and nuts holding engine mount bracket to body. (Scheme 27) With chain lift, slowly raise engine and verify all cables, hoses and wiring have been disconnected.
11. Remove transaxle mounting bracket bolts. Remove left mount insulator bolt. Tilt transaxle downward. Lift engine and transaxle assembly up and out of vehicle.

INTAKE MANIFOLD

FRONT COVER OIL SEAL

Note. Front cover oil seal is replaced during removal and installation of oil pump. See OIL PUMP under ENGINE OILING.

REAR CRANKSHAFT OIL SEAL

Note. Rear crankshaft oil seal is replaced during cylinder block overhaul procedures. See CYLINDER BLOCK ASSEMBLY under OVERHAUL.

Cylinder Head

Inspect cylinder head for warpage at deck surface. Resurface cylinder head if warpage exceeds specification. See CYLINDER HEAD table under ENGINE SPECIFICATIONS. Replace cylinder head if camshaft bearing surface is damaged.

Valve Springs

Inspect valve spring free length and out-of-square. Replace valve springs if not within specification. See VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS. Install all valve springs with painted area toward spring retainer. (Scheme 29)and (Scheme 30).

Scheme 28

Scheme 29

Valve Stem Oil Seals

Ensure valve stem diameter, valve guide diameter and valve stem clearance are within specification. See CYLINDER HEAD and VALVES & VALVE SPRINGS tables under ENGINE SPECIFICATIONS.

Valve Guides

1. Check valve stem and valve guide diameter to determine clearance. See «CYLINDER HEAD»(ref-121832-S04210971602001091100000) and «VALVES & VALVE SPRINGS»(ref-121832-S39260053002001091100000) tables under ENGINE SPECIFICATIONS. If clearance exceeds service limits, valve guide can be replaced with an oversize valve guide. Remove valve guide from cylinder head using valve guide remover/installer (09222-32200). Press valve guide out toward combustion chamber side of cylinder head.
2. Machine cylinder head valve guide bore to specification for oversize valve guide. See «OVERSIZE VALVE GUIDE SPECIFICATIONS»(ref-121832-S18452705112001091800000) table. Note intake valve guides are shorter than exhaust valve guides. Using valve guide installer (09221-29000A and 09221-22000B), press new valve guide into cylinder head from top. Ensure valve guide is installed to proper height. See «CYLINDER HEAD»(ref-121832-S04210971602001091100000) table under ENGINE SPECIFICATIONS. CAUTION: DO NOT install valve guide with same diameter as one removed.
3. Check guide clearance of new valve guides. Ream as necessary. Check valve seat contact.

OVERSIZE VALVE GUIDE SPECIFICATIONS

Valve Seats

1. To replace valve seats, cut away most of seat insert wall (at normal room temperature). Remove valve seat and machine seat insert bore to designated dimension. (Scheme 31) See «OVERSIZE VALVE SEAT SPECIFICATIONS»(ref-121832-S38753969512001091100000) table.
2. Heat cylinder head to 480°F (250°C), and press replacement seat into cylinder head. Ensure valve seat height is within specification. Cut valve seat to proper angle to obtain correct seat width.

Scheme 30

OVERSIZE VALVE SEAT SPECIFICATIONS

Fitting Pistons

1. Measure piston diameter slightly above bottom of piston skirt, at 90-degree angle to piston pin. If piston diameter is not within specification, replace piston with appropriate size. See «PISTONS, PINS & RINGS»(ref-121832-S11688581102001091100000) table under ENGINE SPECIFICATIONS.
2. Measure cylinder bore diameter at top of bore, at center of bore, and at bottom of bore. If cylinder bore diameter or taper is not within specification, machine cylinder bore. See «CYLINDER BLOCK»(ref-121832-S01041236962001091100000) table under ENGINE SPECIFICATIONS. New oversize pistons should now be installed. See «OVERSIZE PISTON & PISTON RING SPECIFICATIONS»(ref-121832-S39533857882001091800000) table.
3. If piston-to-cylinder bore clearance is not within specification, replace piston and/or machine cylinder bore. See «PISTONS, PINS & RINGS»(ref-121832-S11688581102001091100000) table under ENGINE SPECIFICATIONS.

OVERSIZE PISTON & PISTON RING SPECIFICATIONS

Piston Rings

Ensure ring end gap and side clearance are within specification. See PISTONS, PINS & RINGS table under ENGINE SPECIFICATIONS. DO NOT use ring expander to install oil ring side rails. Properly position ring end gaps around circumference of piston before installing. see scheme 14

Scheme 31

Rod Bearings

Note position of connecting rod in relation to bearing cap before removing. Ensure bearing oil clearance and side play are within specification. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS and CONNECTING RODS tables under ENGINE SPECIFICATIONS. Ensue rod bearings notches are properly aligned during assembly.

Crankshaft & Main Bearings

1. Check condition of crankshaft journals and bearings. Check all oil holes for clogging.
2. Check diameters of main bearing journals and connecting rod bearing journals. Check journals for taper and out-of-round. Check crankshaft end play. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-121832-S05079646742001091100000) table under ENGINE SPECIFICATIONS.
3. Install main bearings with grooved bearing half on upper side, and non-grooved half on lower side. Install bearing caps with arrow on top of cap pointing toward timing belt end of engine. Tighten bearing cap bolts, in 4 to 5 steps, to specification. See «TORQUE SPECIFICATIONS»(ref-121832-S30187821802001091100000) .
4. Measure outside diameter of crankshaft journal and crank pin. Measure inside diameter of bearing. Difference is oil clearance. Ensure clearance is within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-121832-S05079646742001091100000) table under ENGINE SPECIFICATIONS. Oil clearance can also be determined using Plastigage method.
5. Ensure crankshaft end play is within specified limit. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-121832-S05079646742001091100000) table under ENGINE SPECIFICATIONS.

Cylinder Block

1. Visually check block for scoring, rusting and corrosion. Check for cracks. Check cylinder block deck warpage. Ensure warpage does not exceed specification. See «CYLINDER BLOCK»(ref-121832-S01041236962001091100000) table under ENGINE SPECIFICATIONS. If warpage exceeds specification, machine surface. DO NOT remove more than a combined total of .008" (0.20 mm) material from cylinder head or block gasket surfaces.
2. Check cylinder bore wear and taper. Measure cylinder bore diameter near top, at center and near bottom of bore. If cylinder bore diameter or taper is not within specification, machine cylinder bore. See «CYLINDER BLOCK»(ref-121832-S01041236962001091100000) table under ENGINE SPECIFICATIONS. New oversize pistons and rings should now be installed. See «OVERSIZE PISTON & PISTON RING SPECIFICATIONS»(ref-121832-S39533857882001091800000) table.

Rear Oil Seal

Carefully remove old seal case and seal from rear of block. Use Installer (09231-33000) to drive NEW oil seal into oil seal case. Apply sealant to mating surface of oil seal case. Install and tighten bolts to specification. See TORQUE SPECIFICATIONS .

Oil Pressure

At curb idle and with oil temperature 167-194°F (75-90°C), normal oil pressure should be at least 11.4 psi (0.8 kg/cm 2 ).