Engine Mechanical 3.1l v6 - VIN [M] 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.

Engine Code & Partial VIN

An engine code (3 characters) and a partial VIN (9 characters) are stamped on cylinder block, in one of the following places.

1. Top of cylinder block, above front cover.
2. On cylinder block flange, where engine mates to transaxle (may be on either side of engine).

Engine code L82 identifies 3.1L V6 SFI engine. If second character of partial VIN is "S", engine is a 1995 model year.

VALVE CLEARANCE (LASH) ADJUSTMENT

Note. If engine is equipped with original rocker arm studs, it is neither necessary nor possible to adjust valve clearance. If engine is equipped with replacement rocker arm studs that allow for valve lash adjustment (because valves and seats were reconditioned), adjust valve lash.

Remove valve covers. Rotate crankshaft until cylinder No. 1 is at TDC of compression stroke. Begin by adjusting exhaust valve of cylinder No. 1. See VALVE CLEARANCE ADJUSTMENT SEQUENCE table. While trying to rotate push rod with thumb and forefinger, loosen nut on rocker stud until push rod just starts to rotate. This is considered zero lash. Tighten nut an additional 1 1/2 turns (this centers the lifter plunger).

VALVE CLEARANCE ADJUSTMENT SEQUENCE

TROUBLE SHOOTING

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

GENERAL PRECAUTION

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

Disconnect negative battery cable. Loosen fuel tank filler cap. Connect Fuel Pressure Gauge (J-34730-1) to fuel line fitting (wrap shop towel around fitting to absorb leakage). Place gauge bleed hose into container. Open bleed valve to release pressure.

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 & Installation

1. Release fuel system pressure. See «FUEL PRESSURE RELEASE»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m__fuel-pressure-release) . Remove top half of air cleaner assembly. Remove throttle body duct. Drain cooling system. Disconnect control cables, coolant hoses, electrical connectors, vacuum hoses, and fuel lines as necessary.
2. Remove serpentine drive belt. Remove alternator. Disconnect power steering lines from pump. Remove radiator fan. Remove vent tube from transaxle. Support engine from above with Engine Support Fixture (J-28467) and Adapter Leg (J-36462). Loosen, but DO NOT remove, top 2 A/C compressor bolts. Raise and support vehicle. Remove front wheels.
3. Remove left and right splash shields. At timing chain end of engine, remove engine mount strut near crankshaft balancer. Disconnect electrical connectors from ABS wheel speed sensors (if equipped) and suspension supports.
4. Separate ball joint studs from steering knuckles. Remove stabilizer shaft from control arms and suspension supports. Remove bolts securing left suspension support to body. Lower the suspension support and control arm as an assembly. Use same procedure to remove right suspension support and control arm assembly.
5. Disengage drive axles from transaxle, then support them with wire. See the «AXLE SHAFTS - FRONT»(/buick/skylark/vii-1992-1998/remont/axle-shafts/#axle-shafts-front) article in the DRIVE AXLES section. Remove oil filter and adapter. Remove torque converter cover (A/T) or flywheel access cover (M/T). Remove starter.
6. Remove A/C compressor (leave hoses connected). Disconnect exhaust pipe from manifold. Remove engine mount strut bracket from engine (near crankshaft balancer). On A/T models, disconnect transaxle cooler lines from radiator. Remove transaxle dipstick tube.
7. On all models, put a suitable support table (such as a heavy table on rollers) under engine and transaxle assembly. Lower vehicle until engine and transaxle assembly just begins to rest on table. Remove remaining engine and transaxle mounts. Raise vehicle, leaving engine and transaxle assembly on table. Separate engine from transaxle. To install, reverse removal procedure. Fill and bleed cooling system. See «COOLING SYSTEM BLEEDING»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m__cooling-system-bleeding) .

Removal

Manufacturer only provides procedure for removing lower intake manifold, which involves removing upper intake manifold. See INTAKE MANIFOLD (LOWER) .

Installation

Clean gasket surfaces. Install NEW gaskets onto cylinder heads. Ensure all holes are aligned. For correct installation, observe reference marks on gaskets (if present). Install the upper intake manifold. (Scheme 22) Using a crisscross pattern, tighten bolts to specification. See TORQUE SPECIFICATIONS. To complete installation, reverse removal procedure. Fill and bleed cooling system if it was drained. See COOLING SYSTEM BLEEDING.

1. Release fuel system pressure. See «FUEL PRESSURE RELEASE»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m__fuel-pressure-release). Remove top half of air cleaner assembly. Remove throttle body duct. Drain cooling system. Disconnect EGR pipe from exhaust manifold. Remove serpentine drive belt.
2. Disconnect power brake vacuum hose from manifold. Disengage power steering lines from retainers at alternator bracket. Remove alternator. Disconnect spark plug wires. Remove ignition coil pack and EVAP solenoid as an assembly. Disconnect vacuum lines, coolant hoses and electrical connectors as necessary.
3. Remove MAP sensor. Remove bolts securing upper intake manifold to lower intake manifold. Remove upper intake manifold and throttle body as an assembly. Disconnect fuel lines from fuel rail. Support engine from above with Engine Support Fixture (J-28467-A) and Adapter Leg (J-36462). Remove engine mount assembly. Remove power steering pump (leave hoses connected).
4. Remove coolant outlet housing. Remove rocker arm covers. Remove bolts securing lower intake manifold to cylinder heads. (Scheme 22) Remove lower intake manifold. If necessary, loosen rocker arms and remove push rods to remove gaskets.

1. Clean gasket surfaces. Apply a 7/32" (5-6 mm) bead of RTV sealant to front and rear ridges of cylinder block sealing surfaces. (Scheme 22) Install NEW gaskets onto cylinder heads. Ensure all holes are aligned. For correct installation, observe reference marks on gaskets (if present).
2. Intake push rods (marked Orange ) are shorter than the exhaust push rods (marked Blue ). Install push rods and rocker arms in original locations. If the vehicle is equipped with rocker arm studs that allow for adjustment of valve lash, adjust valve lash. Refer to the «VALVE CLEARANCE (LASH) ADJUSTMENT»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m__valve-clearance-lash-adjustment) procedures under ADJUSTMENTS.
3. Install lower intake manifold. Using a crisscross pattern, tighten lower intake manifold vertical bolts to specification, then tighten lower intake manifold diagonal bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m__torque-specifications). To complete installation, reverse removal procedure. Fill and bleed the cooling system. Refer to «COOLING SYSTEM BLEEDING»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m__cooling-system-bleeding).

Scheme 22

1. Disconnect negative battery cable. Remove top half of air cleaner assembly. Remove throttle body duct. Partially drain cooling system. Disconnect upper radiator hose from thermostat housing. Disconnect coolant by-pass pipe from water pump and exhaust manifold.
2. Remove heat shield from exhaust crossover pipe. Disconnect exhaust crossover pipe from manifold. Disconnect spark plug wires. Remove heat shield, nuts and exhaust manifold.

Reverse removal procedure using NEW gasket. Tighten exhaust manifold fasteners to specification. See TORQUE SPECIFICATIONS . Fill and bleed cooling system. See COOLING SYSTEM BLEEDING .

1. Disconnect negative battery cable. Remove top half of air cleaner assembly. Remove throttle body duct. Remove heat shield from exhaust crossover pipe. Disconnect exhaust crossover pipe from manifold. Remove oxygen sensor. Disconnect EGR pipe from manifold.
2. Raise and support vehicle. Remove transaxle oil fill tube (A/T). Disconnect exhaust downpipe from manifold. Disconnect exhaust pipe from catalytic converter flange. Support catalytic converter. Remove torque converter heat shield from body. Remove heat shield and exhaust manifold nuts. Remove exhaust manifold through bottom of engine compartment.

Reverse removal procedure using NEW gasket. Tighten exhaust manifold fasteners to specification. See TORQUE SPECIFICATIONS . Fill and bleed cooling system. See COOLING SYSTEM BLEEDING .

Removal (Left)

1. Release fuel system pressure. See «FUEL PRESSURE RELEASE»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m__fuel-pressure-release) . Drain the cooling system. Remove the lower intake manifold. Refer to «INTAKE MANIFOLD (LOWER)»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m) . Remove exhaust crossover pipe.
2. Remove rocker arm covers. Remove rocker arm nuts, rocker arms, and push rods. Remove oil dipstick tube. Remove cylinder head bolts, cylinder head and gasket.

Removal (Right)

Release fuel system pressure. See FUEL PRESSURE RELEASE . Drain the cooling system. Remove the lower intake manifold. Refer to INTAKE MANIFOLD (LOWER) . Remove exhaust crossover pipe. Remove rocker arm covers. Remove rocker arm nuts, rocker arms, and push rods. Remove cylinder head bolts, cylinder head and gasket.

Inspection (Left & Right)

If warpage of cylinder head gasket surface exceeds specification, machine surface. See CYLINDER HEAD SPECIFICATIONS table under ENGINE SPECIFICATIONS. DO NOT remove more than .010" (.25 mm) of material from original surface.

Installation (Left & Right)

1. Clean cylinder head bolt threads and cylinder block holes. Install gasket on cylinder block with THIS SIDE UP mark up (if equipped). Ensure all holes align with cylinder block. Install cylinder head. Apply GM Sealant (1052080) to head bolt threads.
2. Tighten cylinder head bolts to specification in sequence. See the «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m__torque-specifications). To complete installation, reverse removal procedure. (Scheme 23) Fill and bleed the cooling system. Refer to «COOLING SYSTEM BLEEDING»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m__cooling-system-bleeding).

Scheme 23

1. Disconnect negative battery cable. Drain cooling system. Support engine from above with Engine Support Fixture (J-28467) and Adapter Leg (J-36462). Remove engine mount assembly. Remove engine mount bracket support. Remove serpentine drive belt.
2. Remove power steering pump (leave hoses connected). Loosen top 2 A/C compressor bolts. Raise and support vehicle. Remove right front wheel and inner splash shield. Remove flexplate/flywheel cover. Remove bolt and washer securing crankshaft balancer. Use a puller to remove crankshaft balancer.
3. Remove serpentine drive belt tensioner. Remove engine mount strut between top of radiator panel and left side of engine. Disconnect electrical connectors from ABS front wheel speed sensors (if equipped) and suspension supports. Separate right ball joint stud from steering knuckle. Disconnect stabilizer shaft from right control arm and right suspension support. Remove bolts, then remove right suspension support and control arm as an assembly.
4. Remove bolts securing A/C compressor to oil pan. Remove oil filter and adapter. Remove engine mount strut bracket. Remove brace between engine and transaxle. Drain crankcase. Remove starter. Remove oil pan. See OIL PAN. Remove crankshaft sensor. Remove lower bolts from front cover. Lower vehicle. Remove coolant by-pass pipe. Disconnect radiator hose from coolant outlet housing. Remove upper bolts and front cover. Remove oil seal from front cover.

1. Apply RTV sealant to sealing surface of front cover. Install NEW front cover oil seal. See «FRONT COVER OIL SEAL»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m) . Apply RTV sealant to keyway in crankshaft and crankshaft damper.
2. Install crankshaft damper using Damper Installer (J-29113). Ensure damper installer threads are at least .20" (5.1 mm) into crankshaft. To complete installation, reverse removal procedure.

Remove serpentine drive belt. Raise and support vehicle. Remove right front wheel and inner fender splash shield. Remove flexplate/flywheel cover. Prevent crankshaft from turning, and remove crankshaft balancer bolt. Remove crankshaft balancer with a puller. Remove crankshaft balancer key. Pry seal out of front cover with a large screwdriver.

Lubricate seal with engine oil. Using Seal Installer (J-35468), install seal with open end toward engine. To complete installation, reverse removal procedure.

TIMING CHAIN

Note. If camshaft sprocket does not come off easily, lightly strike lower edge of sprocket with a plastic mallet.

Rotate crankshaft until cylinder No. 1 is at TDC of compression stroke (align timing mark on crankshaft balancer with mark on front cover). Remove front cover. See FRONT COVER . Remove camshaft sprocket bolt. Remove camshaft sprocket and timing chain. Remove crankshaft sprocket with Crankshaft Sprocket Remover (J-5825-A).

1. Install crankshaft sprocket (if removed) using Installer (J-38612). If camshaft or crankshaft was rotated during removal of chain or sprockets, rotate camshaft and/or crankshaft as necessary to align timing marks. (Scheme 24)
2. Install timing chain onto camshaft sprocket. Hold camshaft sprocket vertically with chain hanging down. Install the timing chain onto the crankshaft sprocket, then the camshaft sprocket onto camshaft. Install and tighten the camshaft sprocket bolt to specification. See «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m__torque-specifications). Lubricate timing chain with engine oil. To complete installation, reverse removal procedure.

Scheme 24

Remove lower intake manifold. See INTAKE MANIFOLD (LOWER) . Remove rocker arms and push rods. Remove bolts and lifter guide. Remove lifters. Mark component locations for installation reference.

If installing old lifters, lubricate lifters and bores with engine oil. If replacing lifters, lubricate lifter and bores with Prelube (1052365). Install the lifters. To complete installation, reverse removal procedure. Tighten nuts and bolts to specification. See TORQUE SPECIFICATIONS .

1. Remove engine. See «ENGINE»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m) . Remove lower intake manifold. See «INTAKE MANIFOLD (LOWER)»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m) . Remove rocker arms and push rods. Remove bolts and lifter guide. Remove lifters. Mark component locations for installation reference. Remove front cover. See «FRONT COVER»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m) .
2. Remove the timing chain and the camshaft sprocket. Refer to «TIMING CHAIN»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m__timing-chain) . Remove oil pump drive assembly from top rear of cylinder block (held in place with a bolt and clamp like a distributor). Remove camshaft thrust plate. Remove camshaft. If necessary, remove camshaft bearings using Remover/Installer (J-33049).

Inspection

If journal runout, lobe lift or oil clearance is not within specification, replace camshaft. See CAMSHAFT SPECIFICATIONS table under ENGINE SPECIFICATIONS.

Lubricate camshaft bearings and lobes with engine oil. Install camshaft. To complete installation, reverse removal procedure. Ensure timing marks are aligned. (Scheme 24) Tighten nuts and bolts to specification. See TORQUE SPECIFICATIONS.

1. Remove transmission. See TRANSMISSION REMOVAL & INSTALLATION article in TRANSMISSION SERVICING (A/T models) or appropriate article in CLUTCHES (M/T models).
2. On M/T models, mark clutch pressure plate and flywheel for installation reference. Remove pressure plate, clutch disc and flywheel. On A/T models, remove flexplate and retainer.
3. On all models, careful pry seal from housing (DO NOT damage sealing surfaces). Note direction of seal installation.

1. Coat inner and outer seal surfaces with engine oil. Install seal on mandrel of Seal Installer (J-34686) until dust lip bottoms against seal installer collar. (Scheme 25)
2. Install seal installer onto crankshaft, aligning dowel pin on seal installer with alignment hole in crankshaft flange. To install seal in seal bore, tighten seal installer handle until collar on seal installer is even with cylinder block.
3. To complete installation, reverse removal procedure. Align reference marks on pressure plate and flywheel (M/T models). Tighten bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m__torque-specifications).

Scheme 25

Note. Thermostat is located between engine block and coolant outlet assembly.

Disconnect negative battery terminal. Drain coolant until level is below thermostat. Remove air cleaner assembly and surge tank hose from coolant outlet. Remove coolant outlet to inlet manifold bolt and nut. Remove coolant outlet. Remove thermostat. (Scheme 26) To install, reverse removal procedure. Refill coolant.

Scheme 26

Disconnect negative battery cable. Drain cooling system. Remove air cleaner (if necessary). Loosen water pump pulley bolts. Remove serpentine drive belt. Remove water pump pulley bolts and pulley. Note position of locator tab on top of water pump for installation reference. Remove bolts, water pump and gasket.

Apply thread sealant to water pump bolts. Install the water pump and NEW gasket. Ensure the locator tab on top of the water pump housing is positioned vertically. Tighten bolts to specification. See TORQUE SPECIFICATIONS . To complete installation, reverse removal procedure. Fill and bleed cooling system. See COOLING SYSTEM BLEEDING .

1. Disconnect negative battery cable. Remove serpentine drive belt. Loosen, but DO NOT remove, A/C compressor upper bolts. Raise and support vehicle. Drain crankcase. Remove right front wheel and inner splash shield. Remove engine mount strut near crankshaft balancer. Disconnect ABS wheel speed sensor connector.
2. Separate right ball joint stud from steering knuckle. Disconnect stabilizer shaft link from right control arm and suspension support. Put an adjustable floor stand under right suspension support. Remove bolts securing right suspension support to body. Lower right suspension support and control arm as an assembly.
3. Remove A/C compressor lower bolts, and position A/C compressor aside with hoses attached. Remove engine mount strut bracket. Remove brace between engine and transaxle. Remove oil filter, starter, and flexplate/flywheel cover. Remove oil pan side bolts, oil pan bottom bolts, and oil pan.

Clean gasket surfaces of oil pan and cylinder block. Apply RTV sealant to tab grooves in rear main bearing. Install oil pan and NEW gasket. Tighten oil pan bottom bolts to specification, then tighten oil pan side bolts. See TORQUE SPECIFICATIONS . To complete installation, reverse removal procedure. Fill crankcase.

Gasket Surface

If warpage of gasket surface exceeds specification, machine cylinder head. See CYLINDER HEAD SPECIFICATIONS table under ENGINE SPECIFICATIONS. DO NOT remove more than .010" (.25 mm) of material from original surface of cylinder head.

Valve Springs

Replace spring if free length, out-of-square, pressure or installed height is not as specified. See VALVES & VALVE SPRINGS SPECIFICATIONS table under ENGINE SPECIFICATIONS.

Valve Stem Oil Seals

If oversize valves are installed, use oversize seals. Ensure seal is fully seated on guide. Intake and exhaust seals are different.

Valve Guides

If valve stem-to-guide oil clearance is not within specification, ream valve guide and install oversize valve. See CYLINDER HEAD SPECIFICATIONS table under ENGINE SPECIFICATIONS. DO NOT knurl valve guides.

Valve Seats

If valve seat width or runout is not within specification, machine or replace valve seat as necessary. See CYLINDER HEAD SPECIFICATIONS table under ENGINE SPECIFICATIONS. Valve seat replacement procedure is not available from manufacturer.

Valves

If valve margin is not within specification, replace valve. See VALVES & VALVE SPRINGS SPECIFICATIONS table under ENGINE SPECIFICATIONS.

Valve Seat Correction Angles

If seat contact is too low (too close to stem) or too wide, use a 70-degree stone to raise or narrow seat.

CYLINDER BLOCK ASSEMBLY

Piston & Rod Assembly

Mark piston with cylinder number for installation in original location. Replace rod if bend or twist exceeds specification. See CONNECTING RODS SPECIFICATIONS table under ENGINE SPECIFICATIONS. Install piston with arrow on top of piston toward front of engine.

Fitting Pistons

1. Measure cylinder bore diameter at top and center of bore. Measure piston diameter at 90-degree angle to piston pin bore, 1/4" below center line of piston pin bore.
2. If piston clearance is not within specification, machine cylinder bore and install oversize piston(s) as necessary. See «PISTONS, PINS & RINGS SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m) table under ENGINE SPECIFICATIONS. DO NOT machine oversize piston to fit cylinder bore, or engine balance will be affected.

Piston Rings

If piston ring end gap or side clearance is not within specification, replace piston rings and/or piston as necessary. See PISTONS, PINS & RINGS SPECIFICATIONS table under ENGINE SPECIFICATIONS. Install piston rings with identification mark on ring land facing top of piston. Properly position end gaps of piston rings around circumference of piston. (Scheme 27)

Rod Bearings

If the connecting rod bearing oil clearance is not within specification, machine crankshaft and replace bearings. Refer to the CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS SPECIFICATIONS table under ENGINE SPECIFICATIONS.

Crankshaft & Main Bearings

Measure the crankshaft main bearing for proper oil clearance, out-of-round and taper. If any measurements are not within specification, machine the crankshaft and replace the bearings. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS SPECIFICATIONS table under ENGINE SPECIFICATIONS.

Thrust Bearing

Measure crankshaft end play (thrust bearing clearance). See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS SPECIFICATIONS table under ENGINE SPECIFICATIONS. If not within specification, replace bearing and/or repair or replace crankshaft.

Cylinder Block Deck Surface

If deck surface warpage exceeds specification, machine surface. DO NOT remove more than .010" (.25 mm) of material from original deck surface.

Valve Lifter Bores

Oversize valve lifters are available. If oversize lifters are installed, stamp oversize on cylinder block near lifter bore to indicate oversize lifters have been installed.

Scheme 27

ENGINE LUBRICATION SYSTEM

A camshaft-driven, gear-type oil pump provides pressurized lubrication through oil filter to main gallery above left side of camshaft center line. (Scheme 28) This gallery provides lubrication to valve lifters on left bank, camshaft bearings, crankshaft and right gallery.

Right gallery supplies oil to valve lifters on right bank. Rocker arms are lubricated by passages in push rods. Slot in front camshaft bearing provides lubrication to camshaft sprocket thrust face. Pressure regulator valve is mounted in oil pump body.

Crankcase Capacity

Engine oil capacity is about 4 qts. (3.8L) without filter change. More oil may be necessary when replacing oil filter.

Oil Pressure

Minimum allowable oil pressure is 15 psi (1 kg/cm 2 ) at 1100 RPM.

Scheme 28

Removal & Disassembly

1. Remove oil pan. See «OIL PAN»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m) under REMOVAL & INSTALLATION. Remove oil pump bolt, oil pump and extension shaft from rear main bearing cap.
2. To disassemble, remove pump cover. DO NOT remove pick-up tube from cover unless loose or broken. If pick-up tube is loose, bent or has been removed, replace pick-up tube and pump cover. WARNING: On some models, pressure regulator valve spring is under pressure. To prevent personal injury, use care when removing cotter pin.
3. Remove gears from pump body. Remove cotter pin securing spring and pressure regulator valve. Remove valve and spring.

1. Inspect components for damage. Using straightedge and feeler gauge, measure gear end clearance. Measure housing pocket depth and diameter. Measure gear diameter and length (thickness). Measure side clearance between gear tooth and housing.
2. Measure gear lash clearance between gear teeth. Check clearance between pressure regulator valve and bore. Replace components or entire assembly if not within specification. Refer to the «OIL PUMP SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m) table.

OIL PUMP SPECIFICATIONS

Note. Use only original equipment gaskets for oil pump service, as gasket thickness is critical.

Reassembly & Installation

1. Coat all components with engine oil. To reassemble, reverse disassembly procedure using NEW pump cover gasket. If installing new pick-up tube, apply Sealant (1050026) to pick-up tube. Install pick-up tube into pump cover using Suction Pipe Installer (J-21882) and plastic hammer.
2. To install, reverse removal procedure. Ensure pump extension shaft is fully engaged. Tighten oil pump bolt to specification. See «TORQUE SPECIFICATIONS»(/buick/skylark/vii-1992-1998/remont/mechanical/#engine-mechanical-31l-v6-vin-m__torque-specifications) .

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

ENGINE SPECIFICATIONS

GENERAL ENGINE SPECIFICATIONS

CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS SPECIFICATIONS

CONNECTING RODS SPECIFICATIONS

PISTONS, PINS & RINGS SPECIFICATIONS

CYLINDER BLOCK SPECIFICATIONS

VALVES & VALVE SPRINGS SPECIFICATIONS

CYLINDER HEAD SPECIFICATIONS

CAMSHAFT SPECIFICATIONS

See also:
• ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION
• COMPUTER RELEARN PROCEDURES
• AXLE SHAFTS - FRONT
• VALVE CLEARANCE ADJUSTMENT SEQUENCE
• FUEL PRESSURE RELEASE
• COOLING SYSTEM BLEEDING
• TORQUE SPECIFICATIONS
• VALVE CLEARANCE (LASH) ADJUSTMENT
• TIMING CHAIN