Engine Mechanical 2.3l 4-cyl - VIN [D] Buick Skylark VII

ENGINE IDENTIFICATION

Note. For repair procedures not covered in this article, see ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION in the GENERAL INFORMATION section.

VEHICLE IDENTIFICATION NUMBER (VIN)

VIN is stamped on a metal tab, which is attached to top left end of instrument panel, near windshield. If eighth character of VIN is "D", vehicle is factory-equipped with a 2.3L DOHC engine. If tenth character of VIN is "S", vehicle is a 1995 model year.

PARTIAL VIN

A partial VIN (9 characters) is stamped on left side of cylinder block. (Scheme 1) If second character of partial VIN is "S", engine is a 1995 model year.

ENGINE CODE

An engine code (3 characters) is stamped on left side of cylinder block. (Scheme 1) Engine code LD2 identifies 2.3L DOHC engine.

Scheme 1

VALVE CLEARANCE ADJUSTMENT

Engine is equipped with non-adjustable hydraulic valve lifters.

TROUBLE SHOOTING

Note. To trouble shoot engine mechanical components, see appropriate table in TROUBLE SHOOTING article in GENERAL INFORMATION.

REMOVAL & INSTALLATION

Note. For reassembly reference, label all electrical connectors, vacuum hoses and fuel lines before removal. Also place mating marks on engine hood and other major assemblies before removal.

FUEL PRESSURE RELEASE

1. Loosen fuel tank cap to release fuel tank pressure. Raise and support vehicle. Disconnect fuel pump electrical connector at gas tank. Start and operate engine until it stalls.
2. Crank engine for an additional 3 seconds to release residual line pressure. Disconnect negative battery cable. Reconnect fuel pump.

COOLING SYSTEM BLEEDING

Fill radiator and coolant reservoir. Leave radiator cap and coolant reservoir cap off. Run engine until upper radiator hose starts to become hot. Ensure radiator is full. Install and tighten radiator cap and coolant reservoir cap.

Note. Remove engine and transaxle as an assembly through bottom of engine compartment.

Removal

1. Release fuel pressure. See «FUEL PRESSURE RELEASE»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__fuel-pressure-release) . Disconnect negative battery cable. Drain cooling system. Discharge A/C system (if equipped) using approved refrigerant recovery/recycling equipment.
2. Disconnect push rod from clutch pedal assembly. Disconnect control cables, coolant hoses, electrical connectors, vacuum hoses, and fuel lines as necessary. Remove air cleaner assembly. Remove cooling fan. Disconnect A/C hose assembly from compressor (if equipped). Discard "O" rings.
3. Remove power steering pump rear bracket along with brake booster vacuum tube. Remove power steering pump (leave hoses connected). Remove clutch slave cylinder. Disconnect exhaust pipe from manifold. Remove heat shield. Support engine from above with Engine Support Fixture (J-28467-A).
4. Remove coolant recovery tank (leave hoses connected). Remove engine mount from timing chain end of engine. Raise and support vehicle. Remove front wheel. Remove right splash shield. Remove radiator air deflector. Remove engine mount strut and transaxle mount. Separate ball joints from steering knuckles.
5. Put a suitable supporting device under the suspension support, crossmember and stabilizer shaft, then remove these components as an assembly. Install Drive Axle Boot Protector (J-34754) on drive axle boots. Remove axle shafts from transaxle, and position them aside.
6. Disconnect A/C lines from oil pan. Remove flywheel housing cover. Put a suitable supporting device under the engine and transaxle assembly. Mark threads on engine upper support fixture hooks for installation reference. Remove engine upper support fixture hooks. Raise vehicle slowly from engine and transaxle assembly. Separate engine from transaxle (note bolt location for reassembly reference).

Installation

1. Assemble engine to transaxle, ensuring bolts are in correct locations. On A/T models, clean torque converter bolts and bolt holes. Apply sealant to bolts. On all models, position engine and transaxle assembly under engine compartment. Lower vehicle until transaxle mount is aligned. Install transaxle mount bolt.
2. Install Engine Support Fixture (J-28467-A) above engine, adjusting it to previous setting. Install engine mount at timing chain end of engine. Install engine mount at transaxle. Raise vehicle. Remove supporting device from below engine and transaxle assembly. Install axle shafts.
3. Install the suspension support, crossmember and the stabilizer shaft assembly. Tighten suspension support rear bolts, then the center bolts and then the front bolts to specification. Refer to «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__torque-specifications) . Connect ball joints. Install engine mount strut. To complete installation, reverse removal procedure. Evacuate and charge A/C system. Fill cooling system and crankcase.

Disconnect negative battery cable. Disconnect electrical connectors and vacuum hoses as necessary. Disconnect air intake tube. Remove throttle cable bracket. Remove oil/air separator. Remove oil filler tube. Remove intake manifold support brace. Remove intake manifold nuts and bolts. Remove intake manifold and gasket.

To install, reverse removal procedure using a NEW gasket on intake manifold (and throttle body, if removed). Numbered side of intake manifold gasket must face intake manifold. Tighten intake manifold nuts and bolts to specification in sequence. (Scheme 2) See the TORQUE SPECIFICATIONS.

Scheme 2

Disconnect negative battery cable. Disconnect oxygen sensor connector. Raise and support vehicle. Remove exhaust manifold brace bolt. Remove upper heat shield. Disconnect exhaust pipe from manifold. Lower vehicle. Remove exhaust manifold nuts. Remove exhaust manifold, seals and gaskets.

To install, reverse removal procedure using NEW gaskets. Tighten bolts to specification in sequence. See TORQUE SPECIFICATIONS. (Scheme 2) If oxygen sensor was removed, coat threads with anti-seize compound before installation.

1. Disconnect negative battery cable. Drain cooling system. Disconnect heater hose and throttle body hose from water outlet. Remove exhaust manifold. See «EXHAUST MANIFOLD»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d).
2. Remove camshaft housings. See «INTAKE CAMSHAFT & HOUSING»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__intake-camshaft-housing) and «EXHAUST CAMSHAFT & HOUSING»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__exhaust-camshaft-housing). Remove oil filler tube. Remove air intake duct. Remove throttle cable bracket (leave cable connected to throttle body). Remove throttle body from intake manifold, and set it aside (leave harness and cable connected).
3. Disconnect electrical connectors, vacuum hoses, and coolant hoses as necessary. Remove intake manifold brace. Remove cylinder head bolts in the reverse order of the tightening sequence. (Scheme 3) Remove cylinder head and gasket.

Inspection

See CYLINDER HEAD under OVERHAUL .

Clean threads of cylinder head bolts and bolt holes. Lightly coat bolt threads with engine oil. Install NEW gasket, ensuring all holes are aligned with cylinder block. Install the cylinder head and tighten cylinder head bolts to specification in sequence. Refer to the TORQUE SPECIFICATIONS. To complete installation, reverse removal procedure. (Scheme 3)

Scheme 3

1. Disconnect negative battery cable. Drain cooling system. Remove coolant recovery tank. Remove serpentine drive belt. Remove alternator (leave wiring attached). Attach Engine Support Fixture (J-28467-A) to engine with alternator bolt. Remove bolts from upper half of front cover. (Scheme 5)
2. Remove engine mount assembly from timing chain end of engine. Remove engine lift bracket. Raise and support vehicle. Remove right front wheel and splash shield. Remove crankshaft balancer bolt. Remove crankshaft balancer with a puller. Remove lower bolts from front cover. Lower vehicle. Remove front cover and gaskets.

To install, reverse removal procedure using NEW gasket. Lubricate front seal with grease before installing crankshaft balancer. To complete installation, reverse removal procedure. Tighten nuts and bolts to specification. See TORQUE SPECIFICATIONS . Fill cooling system.

Remove front cover. See FRONT COVER . Support cover, and drive seal from rear of cover. Note direction of seal installation. To install, use Seal Installer (J-36010).

TIMING CHAIN & SPROCKETS

1. Remove the front cover. See «FRONT COVER»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d). Rotate the crankshaft in normal direction of rotation (clockwise, as viewed from front of engine) until cylinder No. 1 is at TDC of compression stroke. (Scheme 4) Mark on crankshaft sprocket must be aligned with mark on cylinder block. Timing alignment pin holes in camshaft sprockets must be aligned with holes in timing chain housing. (Scheme 4) Install Camshaft Alignment Pins (J-36008) through camshaft sprocket holes and into timing chain housing.
2. Remove timing chain guides. (Scheme 5) Ensure slack part of timing chain is above chain tensioner. Raise and support vehicle. Remove chain tensioner bolts. Slide a screwdriver blade between chain and tensioner shoe while pulling shoe outward (this should disengage chain from wear grooves in shoe). If chain tensioner cannot be removed due to pressure of tensioner shoe against chain, go to next step. If chain tensioner can be removed, remove timing chain. CAUTION: To prevent damage to sprocket or timing chain housing, use a puller to remove sprocket from camshaft. DO NOT pry sprocket from camshaft.
3. Lower vehicle. Use Camshaft Sprocket Wrench (J-36013) to keep intake camshaft from turning, and remove sprocket bolt and washer. Reinstall bolt without washer into camshaft, and finger-tighten it. Using a puller (with puller fingers in sprocket relief holes), remove sprocket from intake camshaft. Remove chain tensioner bolts and chain tensioner. Remove timing chain.

1. Install camshaft sprocket (if removed). Clean old sealant off the camshaft sprocket bolt threads and the bolt hole in the camshaft. Apply Adhesive/Sealant (12345493) to threads of camshaft sprocket bolt. Install bolt and washer. Tighten bolt to specification. See «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__torque-specifications).
2. For camshaft positioning, install Camshaft Alignment Pins (J-36008) through camshaft sprocket holes and into timing chain housing. (Scheme 4) Install timing chain onto exhaust camshaft, idler sprocket and crankshaft sprocket. Temporarily remove alignment pin from intake camshaft.
3. Install timing chain onto intake camshaft sprocket. It may be necessary to rotate intake camshaft just far enough to allow chain links to engage sprocket teeth. Reinstall alignment pin into intake camshaft sprocket.
4. Timing marks should be aligned. (Scheme 4) Timing chain should be tight in section between camshaft sprockets, and in section between intake camshaft sprocket and crankshaft. If timing marks are not aligned, repeat procedure.
5. In any case, leave the alignment pins installed. Raise and support the vehicle. To reposition the timing chain tensioner to zero position, make a keeper out of a piece of heavy-gauge wire. Refer to Fig. (Scheme 6). Apply a slight force on the chain tensioner blade to compress the plunger.
6. Insert a small screwdriver into reset access hole, and pry ratchet pawl away from ratchet teeth while forcing plunger completely into hole. (Scheme 6) Install keeper between access hole and blade. Install chain tensioner, ensuring long end is toward crankshaft. Tighten bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__torque-specifications).
7. Lower vehicle enough to reach and remove alignment pins. Rotate crankshaft clockwise 2 full revolutions. Align crankshaft timing marks. If engine is timed correctly, alignment pins will slide in easily. Install timing chain guides. To complete installation, reverse removal procedure.

Scheme 4

Scheme 5

Scheme 6

TIMING CHAIN HOUSING

Note. If you are only going to replace gaskets between timing chain housing and camshaft housings, or between timing chain housing and cylinder block, it is not necessary to fully remove timing chain housing.

1. Disconnect negative battery cable. Remove front cover. See «FRONT COVER»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d) . Raise and support vehicle. Drain cooling system by disconnecting heater hose from thermostat housing. Remove nuts securing water pump to timing chain housing. Remove timing chain and camshaft sprockets. See «TIMING CHAIN & SPROCKETS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__timing-chain-sprockets) .
2. Remove brace between timing chain housing and belt tensioner bracket. Remove 4 bolts securing oil pan to timing chain housing. If fully removing housing, remove stud from lowest point on timing chain housing (if left installed, the stud prevents removal of housing).
3. In any case, lower vehicle. Remove bolts securing timing chain housing to camshaft housings. Remove timing chain housing and gaskets (if necessary, raise engine slightly from above).
4. If removing timing chain idler sprocket and bearing, see «TIMING CHAIN IDLER SPROCKET & BEARING»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__timing-chain-idler-sprocket-bearing) .

1. Replace oil pan gasket if damaged. If silicone bead at corner joints is damaged, repair it by applying just enough silicone sealant to restore it to its original dimension (too much sealant may cause part misalignment, resulting in oil leaks).
2. Ensure dowel pins are installed in cylinder block. Install timing chain housing with NEW gaskets (without sealer). Install and hand-tighten all timing chain housing bolts, then tighten to specification. See «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__torque-specifications) . To install remaining components, reverse removal procedure. Fill cooling system.

TIMING CHAIN IDLER SPROCKET & BEARING

Note. Replace bearing whenever idler sprocket is removed.

1. Remove timing chain housing. See «TIMING CHAIN HOUSING»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__timing-chain-housing). Remove snap ring securing bearing in housing. (Scheme 7) Install Remover/Installer Plate (J-36998-4) on front side of housing, engaging alignment pins into bolt holes in housing.
2. Using Handle (J-36998-2), press sprocket out of bearing. Reposition remover/installer plate onto rear side of housing, engaging water pump studs into holes in plate. Using Remover/Installer (J-36998-1) and Handle (J-36998-2), press bearing out of housing.

Clean snap ring groove in housing. Coat surfaces of housing and NEW bearing with Sealant (12345493). Install remover/installer plate on front side of housing. Using remover/installer and handle, press bearing into housing. Reposition remover/installer plate to rear side of housing. Using remover/installer and handle, press idler sprocket through bearing. Install bearing snap ring. Install timing chain housing. See TIMING CHAIN HOUSING .

Scheme 7

INTAKE CAMSHAFT & HOUSING

1. Disconnect negative battery cable. Disconnect electrical connector. Remove bolts, and remove ignition coil and module assembly by pulling it straight up. (Scheme 8) Remove power steering pump (leave hoses connected).
2. Remove oil/air separator with hoses attached at separator. Disconnect vacuum line from fuel pressure regulator. Disconnect fuel injector harness connector. Remove fuel line clamp from top of intake camshaft housing. Remove fuel rail bolts.
3. Remove fuel rail (leave fuel lines attached). Cover injector openings in cylinder head. Cover injector nozzles. Remove timing chain and camshaft sprockets. See «TIMING CHAIN & SPROCKETS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__timing-chain-sprockets). Remove bolts securing timing chain housing to camshaft housing.
4. Remove bolts that secure camshaft housing cover to camshaft housing. Working in reverse order of tightening sequence, evenly loosen and remove bolts securing camshaft housing to cylinder head (leave 2 bolts loosely in place to keep camshaft housing in place while separating cover from housing). (Scheme 9)
5. Install 4 camshaft housing-to-cylinder head bolts into tapped holes in camshaft housing cover. Evenly tighten bolts to separate cover from housing. Remove 2 loosely installed camshaft housing bolts. Remove camshaft housing cover and seals. NOTE: If removing lifters, keep them in order; they must be installed in their original locations. To prevent bleed-down, store lifters upside down in clean engine oil.
6. Install and hand-tighten one camshaft housing bolt to keep camshaft housing in place while removing camshaft and lifters. For installation reference, note position of dowel pin (on timing chain sprocket) in relation to camshaft housing. Remove camshaft. Remove camshaft housing and lifters as an assembly. If necessary, remove lifters from camshaft housing.

If camshaft journal diameter, lobe lift, end play or oil clearance is not within specification, replace components as necessary. See CAMSHAFT table under ENGINE SPECIFICATIONS. Check camshaft housing. See CAMSHAFT HOUSING under OVERHAUL.

Note. If replacing camshaft or lifters, add Engine Oil Supplement (1052367) to crankcase. If camshaft is replaced, lifters must also be replaced.

1. Ensure dowel pins aligning camshaft housing with cylinder head are installed. Install camshaft housing with a NEW gasket (no sealant required). Loosely install one camshaft housing bolt to keep camshaft housing in place while installing lifters and camshaft.
2. Coat lifters and camshaft with Prelube (12345501). Install lifters in their original locations. Install camshaft, ensuring dowel pin on timing chain sprocket is in same position as when removed. Install NEW Green seals into cover (no sealant required).
3. Remove bolt installed to keep camshaft housing in place. Apply Pipe Sealant (1052080) to threads of bolts securing housing to cylinder head 6and cover to housing. Tighten camshaft housing bolts to specification in sequence. Refer to the «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__torque-specifications) Refer to Fig. (Scheme 9).
4. Install timing chain housing and timing chain in reverse order of removal. Lubricate NEW "O" ring seals with engine oil, and install them onto injectors. Install fuel rail. To install remaining components, reverse removal procedure.
5. If a spark plug boot connector remained on a spark plug when ignition coil and module assembly was removed, remove it from spark plug and install it onto ignition coil and module assembly. Set ignition coil and module assembly in place and press straight down to install assembly onto spark plugs.
6. Clean oil from threads of bolts securing assembly to camshaft housing. Apply thread sealant to bolt threads. To complete installation, reverse removal procedure.

Scheme 8

Scheme 9

EXHAUST CAMSHAFT & HOUSING

Removal (DOHC)

1. Disconnect negative battery cable. Disconnect electrical connector. Remove bolts, and remove ignition coil and module assembly by pulling it straight up. (Scheme 8) Disconnect oil pressure switch connector.
2. Remove the timing chain and camshaft sprockets. Refer to «TIMING CHAIN & SPROCKETS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__timing-chain-sprockets). Remove bolts securing timing chain housing to camshaft housing. Remove bolts securing camshaft housing cover to camshaft housing. Working in reverse order of tightening sequence, evenly loosen and remove bolts securing camshaft housing to cylinder head (leave 2 bolts loosely in place to keep camshaft housing in place while separating cover from housing). (Scheme 9)
3. Install 4 camshaft housing-to-cylinder head bolts into tapped holes in camshaft housing cover. Evenly tighten bolts to separate cover from housing. Remove 2 loosely installed camshaft housing bolts. Remove camshaft housing cover and seals. NOTE: If removing lifters, keep them in order; they must be installed in their original locations. To prevent bleed-down, store lifters upside down in clean engine oil.
4. Install and hand-tighten one camshaft housing bolt to keep camshaft housing in place while removing camshaft and lifters. For installation reference, note position of dowel pin (on timing chain sprocket) in relation to camshaft housing. Remove camshaft. Remove camshaft housing and lifters as an assembly. If necessary, remove lifters from camshaft housing.

If camshaft journal diameter, lobe lift, end play or oil clearance is not within specification, replace components as necessary. See CAMSHAFT table under ENGINE SPECIFICATIONS. Check camshaft housing. See CAMSHAFT HOUSING under OVERHAUL.

Note. If replacing camshaft or lifters, add Engine Oil Supplement (1052367) to crankcase. If camshaft is replaced, lifters must also be replaced.

1. Ensure dowel pins aligning camshaft housing with cylinder head are installed. Install camshaft housing with NEW gasket (no sealant required). Loosely install one camshaft housing bolt to keep camshaft housing in place while installing lifters and camshaft.
2. Coat lifters and camshaft with Prelube (12345501). Install lifters in their original locations. Install camshaft, ensuring dowel pin on timing chain sprocket is in same position as when removed. Install NEW Orange or Red seals into cover (no sealant required).
3. Remove bolt installed to keep camshaft housing in place. Apply Pipe Sealant (1052080) to threads of bolts securing housing to cylinder head and cover to housing. Install and tighten camshaft housing bolts to specification in sequence. See «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__torque-specifications). (Scheme 9)
4. Install timing chain housing and timing chain in reverse order of removal. To install remaining components, reverse removal procedure. If a spark plug boot connector remained on a spark plug when the ignition coil and module assembly was removed, remove connector from spark plug and install it onto ignition coil and module assembly.
5. Set ignition coil and module assembly in place and press straight down to install assembly onto spark plugs. Clean oil from threads of bolts securing assembly to camshaft housing. Apply thread sealant to bolt threads. To complete installation, reverse removal procedure.

1. Remove the transaxle. On M/T models, mark pressure plate in relation to flywheel for installation reference. Remove flexplate/ flywheel assembly. Remove seal housing bolts, seal housing and gasket. (Scheme 18)
2. Note direction of seal installation. Lay seal housing onto 2 wood blocks, with transaxle side of seal housing facing down. To prevent seal housing damage, ensure wood blocks contact seal housing at bolt hole bosses (reinforcements). Using a small chisel in seal relief grooves, evenly drive seal out of seal housing without scraping sealing surface.

1. Using Crankshaft Rear Seal Installer (J-36005), press NEW seal into housing. Replace oil pan gasket if it is damaged. If silicone bead at corner joints is damaged, repair it by applying just enough silicone sealant to restore it to its original dimension (too much sealant may cause part misalignment, resulting in oil leaks).
2. Set NEW gasket in place on dowel pins. Lubricate NEW seal lip with engine oil. Install seal housing, but DO NOT install oil pan bolts. Tighten bolts securing seal housing to cylinder block to specification. See «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__torque-specifications) . Install and tighten oil pan bolts to specification.
3. To install remaining components, reverse removal procedure. Apply Sealant (12345493) to flexplate/flywheel bolts before installing them. Align reference marks on pressure plate and flywheel (manual transmission).

OIL FLOW CHECK VALVE

1. Oil flow check valve is located below surface of cylinder block deck, near front of engine, and is accessible with cylinder head removed. (Scheme 21) Attach a slide hammer to check valve using Check Valve Remover (J-38123) or a modified common 3/16 x 4" round-head machine screw. To modify screw, grind 2 flat spots on outside diameter of screw head, parallel with screwdriver slot and 180 degrees across from each other.
2. Insert check valve remover (or modified machine screw) into check valve, then rotate tool 90 degrees so it will lock into indentations in check valve. Pull check valve out of its bore.

Using slide hammer and check valve remover (opposite end), or a hammer and drift punch, drive NEW check valve into its bore until it is seated (normally, check valve will seat slightly below surface).

To remove and install valve lifters, remove camshafts and camshaft housings. See INTAKE CAMSHAFT & HOUSING . Also refer to EXHAUST CAMSHAFT & HOUSING .

1. Disconnect negative battery cable. Drain coolant to level below thermostat. See «COOLING SYSTEM BLEEDING»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__cooling-system-bleeding). Remove inlet housing bolt accessible through exhaust manifold. (Scheme 10)
2. Raise and support vehicle. Remove radiator outlet pipe stud. Remove second coolant inlet housing bolt. Remove inlet housing and thermostat. Clean and inspect mating surfaces.
3. To install, reverse removal procedure. Tighten all fasteners to specification. See «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__torque-specifications). Fill and pressure test system. Inspect for leaks.

Scheme 10

1. Water pump is driven by timing chain idler sprocket and is mounted on rear of timing chain housing. (Scheme 11) Disconnect negative battery cable. Drain cooling system. Remove exhaust manifold. See «EXHAUST MANIFOLD»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d).
2. Remove bolts securing water pump cover to outlet pipe. Remove bolts securing water pump cover to cylinder block. Remove nuts securing water pump body to timing chain housing. Remove water pump body and water pump cover as an assembly. Separate components as necessary.

Note. Before installing water pump, read the entire installation procedure. It contains important information about tightening sequences that affect sealing.

1. If cover was separated from body during removal, join these components with a NEW gasket, and hand-tighten bolts. Apply bearing grease to splines of water pump drive. Set cover and body assembly into position.
2. Install and hand-tighten bolts securing cover to cylinder block. Install and hand-tighten nuts securing body to timing chain housing. Lubricate outlet pipe "O" ring with antifreeze. Connect outlet pipe. Install and hand-tighten bolts.
3. Tighten bolts and nuts to specification in the following sequence. See «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__torque-specifications) . Pump Assembly-To-Timing Chain Housing Nuts Pump Cover-To-Pump Body Bolts Pump Cover-To-Cylinder Block Bolts Outlet Pipe-To-Cover Bolts
4. To complete installation, reverse removal procedure. Fill cooling system.

Scheme 11

1. Disconnect negative battery cable. Raise and support vehicle. Drain crankcase. Drain cooling system. Remove flywheel cover. Remove right front wheel. Remove splash shield. Remove serpentine drive belt. Remove A/C compressor, and position it aside with hoses connected.
2. Support engine from above with Engine Support Fixture (J-28467-A). Remove engine mount from bottom front end of engine. Remove radiator outlet pipe bolts. Remove A/C lines and radiator outlet pipes from oil pan. Remove exhaust manifold brace.
3. Remove bolt and nut securing oil pan to flywheel cover. Remove flywheel cover stud (for clearance during removal). Disconnect radiator outlet pipe from lower radiator hose and oil pan. Disconnect oil level sensor connector. Remove oil pan bolts, pan and gasket.

If oil pan gasket is not damaged, reuse it. Install oil pan and gasket. Loosely install oil pan bolts. Place spacer in approximate installed location, but allow clearance to tighten pan bolt located directly above spacer. Tighten oil pan bolts to specification. See TORQUE SPECIFICATIONS . To complete installation, reverse removal procedure.

BALANCE SHAFTS & HOUSING

Note. If replacing one balance shaft, replace other balance shaft. If replacing drive chain, replace both sprockets.

1. Balance shafts are contained in a housing that is mounted on bottom of cylinder block. (Scheme 12)and (Scheme 14). Remove oil pan. See OIL PAN. Remove oil pump. See «OIL PUMP»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__oil-pump).
2. Check thrust plate. If thrust plate is worn, replace it. If thrust plate is okay, replace balance shafts.
3. Remove cover from balance shaft chain (one bolt and one nut). (Scheme 17) Loosen, but DO NOT remove, bolt securing balance shaft chain guide. If reusing driven sprocket on balance shaft, mark it so it can be installed in same position.
4. Use Crankshaft Holder (J-41088) to prevent crankshaft from turning. Remove driven sprocket bolt (left-hand threads). Remove driven sprocket. If disassembling balance shaft housing after removal, go to next step. Otherwise, remove bolts securing balance shaft housing to cylinder block, and remove housing.
5. Pry oil pump pick-up screen out of balance shaft housing. Remove all except 2 bolts securing balance shaft housing to cylinder block. Loosen all bolts securing housing halves together. Remove 2 remaining bolts, and remove balance shaft housing.

Scheme 12

Note. Balance shaft journals are slightly tapered. This is normal. Balance shaft and housing specifications are not available from manufacturer.

Disassembly & Inspection

1. Remove the bolts securing the housing halves together. (Scheme 12) Disassemble balance shaft housing. If housing is damaged, replace entire assembly. Replace drive chain cover is worn or cracked. If chain guide is cracked, or if grooves are deeper than.045" (1.14 mm), replace chain guide. Replace driven sprocket if damaged.
2. If balance shaft bearing journals are scored or gear teeth are damaged, replace balance shafts or entire assembly as necessary. Bearings are replaceable. Replace chain if links are damaged or if chain is stretched (chain is stretched if it contacts housing or if guide is at end of its travel). Check for worn thrust bearing.

Note. DO NOT install oil pump pick-up screen until specified.

Reassembly

1. Install thrust plate. (Scheme 12) Tighten bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__torque-specifications). Install bearings into housing halves. Apply Lubricant (9985705) to bearings, journals and gears. Lay upper housing upside down on bench.
2. Install balance shafts into upper housing, ensuring timing marks on balance shaft gears are aligned. (Scheme 13) Place lower housing onto upper housing. Tighten bolts securing housing halves to 44 INCH lbs. (5 N.m) in sequence. (Scheme 15)
3. Ensure balance shafts spin freely. If oil pump pick-up screen was removed, install it by tapping it into place with a plastic hammer.

Scheme 13

1. Apply Loctite No. 242 to threads of bolts securing housing to cylinder block. Install housing assembly onto cylinder block, and finger-tighten all bolts. Tighten bolts in sequence to specification. (Scheme 16)
2. Rotate crankshaft until cylinder No. 1 is at TDC. Rotate crankshaft an additional 90 degrees in either direction (keyway on crankshaft should be aligned with split line of main bearing). (Scheme 14) Rotate balance shafts as necessary, then install Balance Shaft Holder (J-41088) onto ends of balance shafts. Balance shafts are now timed in relation to crankshaft.
3. Install chain and driven sprocket onto balance shaft. (Scheme 17) If installing old sprocket, ensure same surface of sprocket, as when removed, faces balance shaft. If installing NEW sprocket, either surface of the sprocket can be placed against balance shaft.
4. Install and finger-tighten (left-hand threads). Install chain guide. While tightly pressing chain guide against chain, temporarily install and tighten chain guide adjustment bolt. Tighten NEW sprocket bolt to specification. See «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d__torque-specifications). Remove balance shaft holder from ends of balance shafts. CAUTION: When adjusting chain tension, use a brass feeler gauge. A steel feeler gauge will not bend properly, resulting in inaccurate adjustment.
5. Loosen adjustment bolt at chain guide. Adjust chain tension as follows: Insert a.040" (1.0 mm) brass feeler gauge between chain and guide. (Scheme 18) Press chain against guide with 3 lbs. (1.4 kg) of force. Tighten chain guide adjustment bolt to specification. Install chain cover. Tighten cover nut and bolt to specification. To complete installation, reverse removal procedure.

Scheme 14

Scheme 15

Scheme 16

Scheme 17

Scheme 18

Gasket Surfaces

Using a straightedge and feeler gauge, measure warpage of cylinder head deck surface and manifold surfaces. See CYLINDER HEAD table under ENGINE SPECIFICATIONS. If warpage exceeds specification, machine or replace cylinder head. DO NOT remove more than .010" (.25 mm) of material from original surface.

Valve Springs

Check squareness, free length and pressure of valve springs. See VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS. Replace any spring that is not within specification.

Valve Stem Oil Seals

Remove seals with Seal Remover (J-36017). Install seals with Seal Installer (J-36007).

Valve Guides

If stem-to-guide oil clearance exceeds specification, ream valve guide and/or replace valve. See VALVES & VALVE SPRINGS table and CYLINDER HEAD table under ENGINE SPECIFICATIONS. Information on valve guide replacement is not available from manufacturer.

Valve Seats

For seat angle and seat width specification, see the CYLINDER HEAD table under ENGINE SPECIFICATIONS. Remove only enough metal to clean seat. Valve seat replacement information is not available from manufacturer.

Valve Face

If resurfacing valve face, remove only enough metal to clean face. For face angle specification, see VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS.

Valve Dimensions

If valve dimensions are not as specified, replace valve. See VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS.

Valve Seat Correction Angles

If seat and face make contact too close to valve stem, grind seat with a 20-degree stone. If seat and face make contact too close to valve margin, grind seat with a 70-degree stone.

Valve Installed Height

Valve installed height is distance from tip of valve stem to top of camshaft housing. If installed height is not as specified, grind valve seat or replace valve as necessary. See the VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS.

CAMSHAFT HOUSING

Measure valve lifter O.D. and lifter bore I.D. Determine oil clearance. Inspect camshaft housing warpage. Replace components if necessary. See VALVE LIFTERS table under ENGINE SPECIFICATIONS.

Piston & Rod Orientation

Arrow on top of piston must face front of engine. Oil hole in connecting rod must face exhaust manifold side of engine. (Scheme 19)

Piston Pin

Remove retainer rings from each end of pin bore. No special tools are required to remove and install the piston pin. If the piston fit is not within specification, replace the piston and/or pin. See PISTONS, PINS & RINGS table under ENGINE SPECIFICATIONS.

Fitting Pistons

Measure the diameter of the piston at a 90-degree angle to the piston pin, at .47" (12 mm) from the bottom of the piston. If piston clearance exceeds specification, replace the pistons and/or machine the cylinders. Refer to the PISTONS, PINS & RINGS table and the CYLINDER BLOCK table under ENGINE SPECIFICATIONS.

Piston Rings

If end gap or side clearance exceeds specification, replace piston and/or rings. See PISTONS, PINS & RINGS table under ENGINE SPECIFICATIONS. Ring No. 2 (second ring) must be installed with mark on ring flat facing upward. Before installing piston, stagger ring end gaps 120 degrees apart. (Scheme 19)

Scheme 19

Rod Bearings

1. Mark the cylinder number on the bearing caps for reassembly reference. If connecting rod side clearance exceeds specification, replace connecting rod and/or crankshaft as necessary. See the «CONNECTING RODS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d) table under ENGINE SPECIFICATIONS.
2. If the connecting rod journal dimensions are not within specification, replace the crankshaft. If oil clearance is not within proper specification, replace the connecting rod bearings. Refer to the «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-23l-4-cyl-vin-d) table.

Crankshaft & Main Bearings

Main bearing caps are numbered 1 through 5. If main bearing journal dimensions are not within specification, replace crankshaft. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS table under ENGINE SPECIFICATIONS. If oil clearance is not within specification, replace bearings.

Thrust Bearing

Thrust bearing is part of main bearing No. 3. Using a rubber mallet, tap crankshaft forward then rearward to seat thrust bearing. With main bearing cap bolts tight, check crankshaft end play. If end play exceeds specification, replace main bearing No. 3 and/or crankshaft. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS table under ENGINE SPECIFICATIONS.

Balance Shaft Drive Sprocket On Crankshaft

1. Inspect sprocket. If replacement is required, drill a hole between 2 teeth of sprocket. Split gear with a chisel to remove it from crankshaft. Ensure crankshaft is free of burrs.
2. Preheat oven to 392°F (200°C) for one hour. Smear some Tempilstik (J-24731-425) material onto teeth of replacement sprocket. Heat gear in oven for 25-30 minutes or until Tempilstik starts to melt. Install gear on crankshaft, ensuring it is fully seated against counterweight.

Cylinder Bores

Measure diameter of cylinder bore at midstroke. If cylinder dimensions are not as specified, machine cylinder as necessary and/or replace piston. See CYLINDER BLOCK table.

Cylinder Block Deck Warpage

If cylinder block deck warpage exceeds specification, machine cylinder head. See CYLINDER BLOCK table. DO NOT remove more than .010" (.25 mm) of material from original surface.

ENGINE OILING SYSTEM

Oil pump is located near rear end of balance shaft housing (accessible after oil pan has been removed). (Scheme 17)and (Scheme 20). A chain at rear end of crankshaft drives long balance shaft, which drives short balance shaft. Short balance shaft drives oil pump. Oil is forced through oil filter to main gallery. (Scheme 21) If oil filter becomes clogged, a by-pass valve in cylinder block opens.

From main gallery, oil is distributed to balance shafts, crankshaft, timing chain hydraulic tensioner, lifters, and camshaft. Main bearings and connecting rod bearings are oiled through passages in crankshaft. Cylinder walls are oiled through a hole in connecting rod. Oil passes through oil flow check valve, into cylinder head, and then into each camshaft housing. Oil is fed to valve lifters and camshaft bearings.

Crankcase Capacity

Oil capacity is 4 qts. (3.8L) without oil filter.

Oil Pressure

Ensure engine is at normal operating temperature. Oil pressure should be at least 15 psi (1.05 kg/cm 2 ) at 900 RPM, or 30 psi (2.11 kg/cm 2 ) at 2000 RPM.

Scheme 20

Scheme 21

OIL PUMP

Remove oil pan. See OIL PAN under REMOVAL & INSTALLATION. Remove oil pump.

Remove oil pump cover. (Scheme 20) Remove oil pump body and gerotor. To remove relief valve, carefully remove drift pin (valve is under spring pressure). If oil pump components are damaged or if clearances and component dimensions are not within specification, replace oil pump. See OIL PUMP SPECIFICATIONS table.

Reassembly & Installation

Coat components with oil. Pack oil pump cavities with petroleum jelly (to primes oil pump). To reassemble and install, reverse removal and disassembly procedure. Tighten bolts to specification. See TORQUE SPECIFICATIONS .

OIL PUMP SPECIFICATIONS

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

GENERAL SPECIFICATIONS

GENERAL SPECIFICATIONS

CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS

CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS

CONNECTING RODS

CONNECTING RODS

PISTONS, PINS & RINGS

PISTONS, PINS & RINGS

CYLINDER BLOCK

CYLINDER BLOCK

VALVES & VALVE SPRINGS

VALVES & VALVE SPRINGS

CYLINDER HEAD

CYLINDER HEAD

CAMSHAFT

CAMSHAFT

CAMSHAFT HOUSING

VALVE LIFTERS

VALVE LIFTERS

See also:
• ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION
• COMPUTER RELEARN PROCEDURES
• FUEL PRESSURE RELEASE
• TORQUE SPECIFICATIONS
• EXHAUST MANIFOLD
• INTAKE CAMSHAFT & HOUSING
• EXHAUST CAMSHAFT & HOUSING
• TIMING CHAIN & SPROCKETS
• TIMING CHAIN IDLER SPROCKET & BEARING
• TIMING CHAIN HOUSING
• COOLING SYSTEM BLEEDING
• OIL PUMP