6.2L v8 Diesel - VIN [J] Chevrolet Forward Control P30

ENGINE IDENTIFICATION

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

Engine can be identified by eighth character of Vehicle Identification Number (VIN). VIN is stamped on a metal plate on top left end of instrument panel, near windshield. See ENGINE IDENTIFICATION table.

Engine can also be identified by engine identification (ID) number, stamped on cylinder block in one of the following locations

1. On right side of timing chain case casting.
2. On engine-to-transmission mating flange, near left cylinder head.
3. At left front of engine block, near cylinder head-to-block mating surface.

ENGINE IDENTIFICATION CODES

VALVE CLEARANCE ADJUSTMENT

Engine is equipped with hydraulic valve lifters. No valve adjustment is required.

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.

ENGINE

Note. Removal and installation information on Commercial Van ("P" Series) is not available from manufacturer. The following procedure only applies to the non-Commercial Van.

Removal & Installation

1. Disconnect batteries. Remove headlight bezels, grille, bumper and lower valance panel. Remove hood latch, coolant recovery bottle, upper fan shroud and tie bar. Remove engine cover. Discharge A/C system using approved refrigerant recovery/recycling equipment, disconnect A/C condenser lines and remove condenser (if equipped).
2. Drain cooling system. Remove radiator, fan and lower shroud. Remove intake manifold. See INTAKE MANIFOLD under REMOVAL & INSTALLATION. Remove the injection pump. See INJECTION PUMP under REMOVAL & INSTALLATION.
3. Raise and support vehicle. Remove P/S pump with hoses attached and lay aside. Disconnect exhaust pipes from manifolds. Remove flywheel cover, torque converter bolts (A/T) and engine mount through-bolts. Disconnect cylinder block heater wires.
4. Remove starter. Disconnect fuel line from fuel pump. Lower vehicle. Remove bellhousing bolts. Discharge A/C system using approved refrigerant recovery/recycling equipment and remove A/C compressor (if equipped). Remove oil filler tube upper bracket.
5. Disconnect engine harness electrical connectors and lay harness aside. Remove air cleaner resonator and bracket. Remove transmission dipstick tube. Disconnect heater hoses from engine. Remove alternator upper bracket.
6. Remove coolant crossover pipe. Attach Engine Lifting Fixture (J-33888) to center intake manifold bolt holes. Support transmission. Remove engine. To install, reverse removal procedure. Fill cooling system. Evacuate and charge A/C system.

Removal

1. Disconnect batteries. Remove air cleaner. Remove PCV and EGR hoses. Remove fuel line bracket and ground strap. Remove A/C compressor rear bracket (if equipped). Remove crankcase depression relief valve.
2. Loosen vacuum pump hold-down clamp (if equipped). Rotate pump to gain access to intake manifold bolt. Remove intake manifold bolts and fuel line clips. Remove intake manifold and gaskets.

Installation

1. Install new manifold gaskets according to emissions rating. Install intake manifold. Tighten intake manifold bolts in sequence to specification. (Scheme 22) See «TORQUE SPECIFICATIONS»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j__torque-specifications).
2. To complete installation, reverse removal procedure. Rotate vacuum pump to correct position, and tighten hold-down clamp (if equipped). (Scheme 23)

Scheme 22

Scheme 23

Disconnect batteries. Raise vehicle. Disconnect exhaust pipe from manifold. Lower vehicle. Disconnect glow plug wires. Remove glow plugs. Remove air cleaner duct bracket. If removing left manifold, remove dipstick tube (if necessary). Remove air conditioning bracket (if equipped). Remove exhaust manifold.

Install exhaust manifold. Tighten bolts to specification. See TORQUE SPECIFICATIONS . To complete installation, reverse removal procedure.

CYLINDER HEAD

Note. Removal and installation information on Commercial Van is not available from manufacturer. The following procedure only applies to the non-Commercial Van.

1. Remove intake manifold. See INTAKE MANIFOLD under REMOVAL & INSTALLATION. Remove injection line clips from brackets. Disconnect injection lines from injector nozzles.
2. Disconnect injection lines from injection pump. Remove injection lines. Remove upper fan shroud. Raise and support vehicle. Disconnect exhaust pipe from manifold. Lower vehicle.
3. Remove valve covers. Mark component location for reassembly reference, including crankshaft position. Remove rocker arm bolts and rocker arm shafts. Note hardened upper end of push rod, indicated by paint stripe. Mark push rods if no paint stripe is visible. Remove push rods.
4. Drain coolant. Remove air cleaner resonator and bracket. Remove transmission fluid and engine oil dipstick tubes. Disconnect necessary coolant hoses. Remove alternator and upper bracket. Remove coolant crossover pipe.
5. Disconnect necessary coolant hoses and ground straps. Remove coolant crossover pipe. Remove cylinder head bolts (rear bolt in left cylinder head may need to remain in head during removal). Remove cylinder head bolts, cylinder head and gasket.

Inspection

See CYLINDER HEAD under OVERHAUL .

1. Clean cylinder head and cylinder block gasket surfaces. Clean cylinder head bolt thread and bolt holes. Apply Sealant (1052080) to head bolt threads and underside of bolt heads. DO NOT apply sealant to head gasket surface. Install rear head bolt in left cylinder head. Install cylinder head. CAUTION: Install push rods with hardened end (indicated by paint stripe) upward to prevent damaging engine. To prevent valve and piston contact during rocker arm shaft installation, rotate crankshaft until positioned as noted in step 3) before tightening rocker arm shaft bolts.
2. Install head bolts and tighten in sequence to specification. (Scheme 24) See «TORQUE SPECIFICATIONS»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j__torque-specifications). Install push rods in original location with hardened end upward.
3. Rotate crankshaft until timing mark on crankshaft damper aligns with "0" mark on timing tab, then rotate crankshaft counterclockwise 3 1/2" (estimate this distance by aligning crankshaft damper mark with first lower water pump bolt). (Scheme 29)
4. Install rocker arm shafts, ensuring push rods are seated in rocker arms. Alternately tighten shaft bolts to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j__torque-specifications). To complete installation, reverse removal procedure.

Scheme 24

Disconnect batteries. Remove drive belts. Raise and support vehicle. Remove crankshaft pulley bolts and pulley. Remove crankshaft damper bolt and washer. Using Damper Puller (J-23523-E), remove crankshaft damper. Pry seal from cover using screwdriver. Note direction of seal lip.

Ensure seal area is free of burrs. Coat seal lip and crankshaft damper sealing surface with engine oil. Install new seal using Seal Installer (J-22101). Install crankshaft damper, washer and bolt. Tighten crankshaft damper bolt to 200 ft. lbs. (269 N.m). To complete installation, reverse removal procedure.

TIMING CHAIN & SPROCKETS

Note. Adjust injection pump timing if timing chain, sprockets or injection pump gears are replaced.

1. Disconnect batteries. Drain coolant. Remove water pump and plate. See WATER PUMP under REMOVAL & INSTALLATION. Remove intake manifold. See INTAKE MANIFOLD under REMOVAL & INSTALLATION.
2. Remove crankshaft pulley bolts and pulley. Remove crankshaft damper bolt and washer. Using Damper Puller (J-23523-E), remove crankshaft damper. Pry front cover oil seal from front cover using screwdriver.
3. Rotate crankshaft until mark on crankshaft damper aligns with "0" mark on timing tab with injection pump gear-to-camshaft gear timing marks aligned. (Scheme 25) Remove injection pump gear-to-injection pump bolts. Remove injection pump gear.
4. Remove baffle (if equipped). Scribe mark injection pump flange in relation to front cover (if unmarked). Remove injection pump mounting nuts. Pull pump from front cover and lay on cylinder block. Remove oil pan-to-front cover bolts and front cover-to-cylinder block bolts.
5. Remove front cover. Measure timing chain free play. See TIMING CHAIN FREE PLAY. Remove camshaft gear from camshaft sprocket. (Scheme 26) Note alignment of timing marks on crankshaft and camshaft sprockets. Remove camshaft sprocket and timing chain. Remove crankshaft sprocket (if necessary).

Timing Chain Free Play

1. Position dial indicator on front of cylinder block with dial indicator tip in contact with center of timing chain between sprockets. Pull chain away from crankshaft and adjust dial indicator to zero.
2. Push chain toward crankshaft and note indicator reading. If chain deflection exceeds .80" (20.3 mm) on used parts or .50" (12.7 mm) on new parts, replace chain. Replace sprockets if worn.

Scheme 25

Scheme 26

1. Install crankshaft sprocket (if removed). Install camshaft sprocket and timing chain as an assembly, ensuring timing marks are aligned. (Scheme 26) Install camshaft gear, washer and bolt. Tighten camshaft gear bolt to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j__torque-specifications).
2. Install new front cover oil seal using Seal Installer (J-22102). Coat seal lip and crankshaft damper sealing surface with engine oil. Apply 3/32" (2 mm) bead of anaerobic sealant to front cover at front cover-to-cylinder block sealing surface. Apply 3/16" (5 mm) bead of RTV sealant to front cover at front cover-to-oil pan sealing surface.
3. Install front cover. Tighten front cover bolts and oil pan bolts to specification. Install baffle (if equipped). If installing new front cover, place a timing mark on new front cover. See MARKING TDC ON FRONT COVER.
4. Install injection pump gasket and injection pump, aligning timing marks on injection pump flange and front cover. Install injection pump gear, ensuring timing marks on injection pump gear and camshaft gear are aligned. (Scheme 25) Tighten gear bolts to specification.
5. Ensure.040" (1.0 mm) minimum clearance exists between baffle and injection pump gear. To complete installation, reverse removal procedure. Fill cooling system. Adjust injection pump timing if timing chain, sprockets or injection pump gears were replaced.

Marking TDC On Front Cover

1. Rotate crankshaft until cylinder No. 1 is on TDC of compression stroke (timing marks on injection pump gear and camshaft gear will be aligned, and slot in injection pump gear will be in 6 o'clock position). (Scheme 25)and (Scheme 27).
2. Install Timing Fixture (J-33042) in place of injection pump without gasket. Install injection pump gear bolts to fasten gear to timing fixture. Install nut finger tight on upper front cover stud to secure timing fixture.
3. Tighten large bolt (18 mm head) on timing fixture to 35 ft. lbs. (47 N.m). Tighten nut on upper front cover stud. Ensure crankshaft did not rotate and timing fixture is not binding. Strike scriber with hammer to mark TDC indicator on front housing. Remove timing fixture.

Scheme 27

1. Disconnect batteries. Remove intake manifold. See INTAKE MANIFOLD under REMOVAL & INSTALLATION. Remove fuel injection lines. Disconnect control cables from injection pump.
2. Disconnect wiring, fuel return line and fuel supply line from injection pump. Cap all fuel line openings. Remove A/C hose retainer bracket (if equipped). Remove oil filler tube and vent hose assembly. Remove grommet.
3. Scribe an alignment mark on front cover and injection pump flange. Remove injection pump gear-to-injection pump bolts, accessible through oil filler neck hole (rotate crankshaft as necessary). Remove injection pump mounting nuts. Remove injection pump and gasket.

1. Install new injection pump gasket. Install injection pump, aligning locating pin on injection pump hub with slot in injection pump gear. Loosely install injection pump mounting nuts.
2. Align timing marks on injection pump flange and front cover. Tighten injection pump mounting nuts to specification. Install injection pump gear-to-injection pump bolts. Tighten bolts to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j__torque-specifications).
3. To complete installation, reverse removal procedure. Ensure fuel lines are properly connected to ports on injection pump. (Scheme 28)

Scheme 28

1. Remove intake manifold. See INTAKE MANIFOLD under REMOVAL & INSTALLATION. Remove fuel injection lines and valve covers.
2. Remove rocker arm shaft bolts and rocker arm shaft. Mark component location for reassembly reference. To disassemble rocker arm shaft, see VALVE TRAIN under «OVERHAUL»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j__overhaul) .
3. If removing push rods, note paint stripe on hardened end of push rod (end closest to rocker arm). If no paint stripe is present, mark hardened end of push rod for reassembly reference.

1. Rotate crankshaft until timing mark on crankshaft damper aligns with "0" mark on timing tab. Rotate crankshaft counterclockwise 3 1/2" (estimate this distance by aligning crankshaft damper mark with first lower water pump bolt). (Scheme 29)
2. Install push rods with hardened end upward in original location (if removed). Install rocker arm assembly in original location, ensuring push rods are seated in rocker arms. Install rocker arm shaft bolts. Alternately tighten shaft bolts to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j__torque-specifications). To complete installation, reverse removal procedure.

Scheme 29

1. Remove intake manifold. See INTAKE MANIFOLD under REMOVAL & INSTALLATION. Remove rocker arm assembly. See ROCKER ARM ASSEMBLY under REMOVAL & INSTALLATION. Remove cylinder head. Remove guide plate clamps, guide plates and lifters.
2. Remove guide plate clamps and guide plates through access holes in cylinder head using mechanical fingers. Remove lifters using Lifter Remover (J-29834) and magnet. Mark lifter location.

Note. Some engines are equipped with standard size and .010" (.25 mm) oversize diameter lifters. Bores fitted with oversize lifters are identified by O.S. stamped on cylinder block pad, adjacent to lifter bore, and on top rail of cylinder case, above lifter bore. Oversize lifters are identified by a number 10 stamped on side of lifter.

1. Check for nicks, burrs or scoring on parts. Ensure lifter roller operates smoothly without excessive play and contains no flat spots.
2. Measure lifter oil clearance. If oil clearance is not within specification, replace lifter with .010" ( mm) oversize lifter if resulting oil clearance is within specification. See VALVE LIFTERS table under «ENGINE SPECIFICATIONS»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j) .

1. Submerge new lifters in clean kerosene or diesel fuel and operate plunger several times. Coat lifter roller and bearings with Assembly Lubricant (1052365). Install lifter into original bore. Install guide plate and guide plate clamp. Tighten clamp bolts to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j__torque-specifications) .
2. After all clamps are installed, rotate crankshaft by hand 2 complete turns to ensure free movement of lifters in guide plates. If crankshaft will not rotate, lifter(s) may be binding in guide plate.
3. Install rocker arm assemblies in proper sequence to prevent piston and valve damage. See ROCKER ARM ASSEMBLY under REMOVAL & INSTALLATION. To complete installation, reverse removal procedure.

Removal (Van)

1. Disconnect batteries. Drain cooling system. Remove grille, bumper, lower valance, coolant bottle and upper tie bar. Remove engine cover. Remove A/C compressor, condenser, radiator, shroud and fan. Remove vacuum pump, oil pump drive or engine speed sensor. Remove cylinder heads. See CYLINDER HEAD under REMOVAL & INSTALLATION.
2. Remove timing chain and sprockets. See TIMING CHAIN & SPROCKETS under REMOVAL & INSTALLATION. Remove valve lifters. See HYDRAULIC VALVE LIFTERS under REMOVAL & INSTALLATION. Remove camshaft thrust plate and spacer (if equipped). Remove camshaft.

Inspect camshaft lobes for signs of flaking or flat spots. Measure camshaft journal diameter. Determine oil clearance. Replace camshaft and/or bearings as necessary if not within specification. See CAMSHAFT table under ENGINE SPECIFICATIONS .

Note. Replace hydraulic lifters if installing new camshaft.

1. If replacing camshaft bearings, see CAMSHAFT BEARINGS under REMOVAL & INSTALLATION. Coat camshaft journals with engine oil and lobes with High Viscosity Oil/Zinc (12345501). Install camshaft. Install thrust spacer with inside chamfer toward camshaft. Install thrust plate.
2. Ensure camshaft end play is.002-.012" (.05-.31 mm). Install camshaft sprocket and timing chain, ensuring timing marks are aligned. (Scheme 26) To complete installation, reverse removal procedure.

Remove rear camshaft plug. Remove inner camshaft bearings using Bearing Remover/Installer (J-6098-01) and Adapter(J-6098-10). Rear inner bearing must be removed with pilot fitted in rear camshaft bearing. Remove front and rear camshaft bearings.

Install rear camshaft bearings, then front camshaft bearings to act as guides for remover/installer pilot. Install inner camshaft bearings. Coat new rear camshaft bore plug with Loctite Sealer (592). Install plug from even with block surface to 1/32" (.8 mm) below surface.

1. Remove oil pan and oil pump. See OIL PAN under REMOVAL & INSTALLATION. Remove rear main bearing cap. Remove lower half of seal from cap. Tap end of upper half of seal with a small drift punch to remove seal from block. Clean block surface and seal grooves.
2. Lubricate new crankshaft seal lips with engine oil. Carefully insert end of one half of new seal into block seal groove. Push this piece into groove until one end of seal extends 1/2" (13 mm) from block.
3. Insert other half of seal into block seal groove. Contact ends of seal halves will be at 4 o'clock and 10 o'clock positions, or 8 o'clock and 2 o'clock positions. This provides proper alignment of main cap with seal lips. Lightly coat seal groove of main bearing cap with Loctite (414).
4. Apply a thin film of anaerobic sealant to bearing cap in specified areas. (Scheme 30) Lightly oil cap bolt threads. Tap main bearing cap into place with brass or leather mallet. Install cap bolts and tighten to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j__torque-specifications). To install remaining components, reverse removal procedure.

Scheme 30

1. Disconnect batteries. Drain coolant. Remove accessory drive belts, fan, fan shroud and pulley. Remove alternator, power steering pump and related brackets as necessary.
2. Disconnect coolant by-pass hose and lower radiator hose from water pump. Remove water pump bolts. Remove water pump and water pump plate as an assembly. Remove water pump plate-to-water pump bolt. Separate water pump from plate.

1. Apply anaerobic sealant to sealing surface of plate and water pump. Install plate to pump with new gasket. Coat water pump bolt threads with Sealant (1052080).
2. Install pump and plate assembly to front cover with new gasket. Tighten bolts to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j__torque-specifications) . To complete installation, reverse removal procedure.

1. Disconnect batteries. Remove engine cover. Remove engine oil dipstick and tube from valve cover. Raise and support vehicle. Remove flywheel cover. Drain crankcase. Disconnect engine oil cooler lines from cylinder block.
2. Remove starter. Remove battery cables, automatic transmission fluid lines and clamps from oil pan. Remove oil pan bolts. Lower oil pan from engine (DO NOT attempt to remove oil pan).
3. Rotate crankshaft until forward crankshaft throw for connecting rods No. 1 and 2 is up. Remove oil pump bolt. Allow oil pump and extension shaft to fall into oil pan. Remove oil pan and oil pump. Remove oil pan rear seal.

Removal (Commercial Van)

1. Disconnect batteries. Raise and support vehicle. Drain crankcase. Remove oil filter. Remove flywheel cover. Remove left front engine mount through-bolt. Raise and support engine. Remove strut rods.
2. Remove battery cables, automatic transmission fluid cooler lines and clamps from oil pan. Move cylinder block heater wire aside (if equipped). Raise and support engine. Remove oil pan bolts, oil pan and oil pan rear seal.

Installation (Both Models)

Apply 3/16" (5 mm) bead of RTV sealant to oil pan sealing surface, inboard of bolt holes. Install oil pan rear seal. Install oil pan. Lower engine. Tighten oil pan bolts to specification. See TORQUE SPECIFICATIONS . To complete installation, reverse removal procedure.

OVERHAUL

1. Replace cylinder head if surface warpage exceeds .006" (.15 mm) across its length or .003" (.08 mm) across its width. DO NOT machine cylinder head surface.
2. Inspect pre-chamber for facial cracks. Replace pre-chamber if facial crack length exceeds 3/16" or if crack reaches head gasket sealing mark. To remove pre-chamber from cylinder head, insert small nylon punch through injector hole. Drive pre-chamber from cylinder head.
3. To install pre-chamber, align pre-chamber with alignment notch in cylinder head. Using 1 1/4" (32 mm) socket and hammer, tap pre-chamber into bore.
4. Measure pre-chamber installed height in 2 or more locations where pre-chamber seats against head gasket shield and sealing ring. Ensure pre-chamber is even with cylinder head or does not protrude from cylinder head more than .002" (.05 mm). Pre-chamber must not be recessed in cylinder head.
5. Measure cylinder head thickness between valve cover gasket surface and cylinder head gasket surface. Replace cylinder head if thickness is less than 3.853" (97.87 mm).

Valve Springs

Measure valve spring pressure. Measure valve spring installed height between spring seat (or top of shim, if shimmed) and top of spring shield. Replace valve spring if pressure or installed height is not within specification. See VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS .

Valve Stem Oil Seals

Intake valve uses upper "O" ring seal. Exhaust valve uses upper "O" ring seal and lower umbrella seal, seated against cylinder head.

Valve Guides

1. Valve guides are part of cylinder head (not replaceable). Measure valve stem-to-guide oil clearance. See CYLINDER HEAD table under «ENGINE SPECIFICATIONS»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j) .
2. If oil clearance is not within specification, ream valve guides using Reamer Set (J-7049) and install oversize valves. Oversize valves are available in .003" (.08 mm) and .015" (.38 mm) oversize.

Valve Seat

No replacement procedure is available from manufacturer. Valve seats are induction hardened. Excessive removal of material may damage valve seat. Measure seat width and runout. See CYLINDER HEAD table under ENGINE SPECIFICATIONS .

Valves

Valves with .003" (.08 mm) and .015" (.38 mm) oversize stems are available for worn valve guides.

VALVE TRAIN

Rocker Arm Assembly

1. To disassemble rocker arm assembly, insert screwdriver into rocker arm shaft bore. Break off end of retainer. Pull out retainer with pliers. Mark rocker arms for reassembly to original location on shaft. Remove rocker arms from shaft.
2. Inspect rocker arms and rocker arm shaft at mating surface for damage. Inspect push rods for bend and wear. Ensure oil passages are clear.
3. To assemble rocker arm assembly, coat rocker arms with engine oil and install on shaft in original locations. Center rocker arms with their corresponding holes on shaft. Install retainers with a 1/2" (13 mm) minimum diameter drift punch.

Hydraulic Valve Lifters

Engine is equipped with roller type hydraulic valve lifters. Lifters are serviced as complete assemblies only. Parts are not interchangeable between lifters.

Piston & Rod Assembly

1. Mark piston and rod assembly for installation to original bore. Mark rod and cap in relation to piston. Assemble rod to piston with rod bearing tang on same side of piston as piston crown indent.
2. Properly position ring end gaps around circumference of piston. (Scheme 31) Install piston and rod assembly in bore with piston crown indent toward outside of engine.

Fitting Pistons

1. Measure cylinder bore diameter 2 1/2" (63.5 mm) below cylinder block deck surface. Measure piston diameter at 90-degree angle to piston pin, on pin center line. Determine piston clearance.
2. If clearance is not within specification, replace piston and/or machine cylinder bore. See CYLINDER BLOCK table and PISTON, PINS & RINGS table under «ENGINE SPECIFICATIONS»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j) .

Piston Rings

Measure piston ring end gap and side clearance. If not within specification, replace piston and/or rings as necessary. See PISTONS, PINS & RINGS table under ENGINE SPECIFICATIONS. Install rings with mark on ring facing upward. Position ring end gaps around circumference of piston as shown. (Scheme 31)

Scheme 31

Rod Bearings

1. Mark rod caps in relation to rod for reassembly reference. Measure rod bearing journal out-of-round, taper and oil clearance. If measurement is not within specification, install new rod bearings. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS table under ENGINE SPECIFICATIONS.
2. Undersize bearings may be used in combination with standard to produce correct clearance. If not within specification after installing new bearings, replace crankshaft. DO NOT machine crankshaft. Ensure rod side play is .007-.025" (.17-.63 mm).

Crankshaft & Main Bearings

1. Mark main bearing caps in relation to cylinder block. Measure main bearing journal diameter, out-of-round and taper. Determine main bearing oil clearance.
2. If measurement is not within specification, replace main bearings. DO NOT machine crankshaft. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS table under «ENGINE SPECIFICATIONS»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j) .
3. For rear main bearing installation, see REAR CRANKSHAFT OIL SEAL under REMOVAL & INSTALLATION. Align thrust bearing surfaces and measure crankshaft end play. See THRUST BEARING.

Thrust Bearing

1. Main bearing No. 3 is thrust bearing. Tighten all other main bearing caps to specification. Tighten thrust bearing to 10 ft. lbs. (14 N.m). Tap crankshaft rearward then forward.
2. Tighten thrust bearing cap to specification. Measure crankshaft end play at front face of thrust bearing. If crankshaft end play is not .004-.010" (.10-.25 mm), replace thrust bearing or crankshaft.

Cylinder Block

1. Measure cylinder block deck surface warpage. If warpage exceeds .006" (.15 mm) over its length or .003" (.08) across its width, replace cylinder block. DO NOT machine cylinder block deck surface.
2. Measure cylinder bore taper and out-of-round. If measurement is not within specification, machine cylinder bore and/or replace piston. See CYLINDER BLOCK table under «ENGINE SPECIFICATIONS»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j) .

ENGINE OILING SYSTEM

Pressurized lubrication is provided by gear-type oil pump. (Scheme 32) Camshaft drives oil pump through shaft of a gear-driven vacuum pump and/or engine speed sensor, depending on engine application. Lubrication flows through external oil cooler then into full-flow oil filter. Non-adjustable oil pressure regulator valve is located in oil pump body.

Main oil gallery supplies oil through drilled passages to camshaft and crankshaft bearings. Oil flows through galleries to valve lifters then through hollow push rods to rocker arms.

Scheme 32

Note. Manufacturer recommends changing oil filter at EVERY oil change.

Crankcase Capacity

Crankcase capacity is 7 quarts (6.6L) including oil filter change.

Oil Pressure

Normal oil pressure is 40-45 psi (2.81-3.16 kg/cm 2 ) at 2000 RPM.

Removal & Disassembly

1. Remove oil pan, oil pump and extension shaft. See OIL PAN under REMOVAL & INSTALLATION. Remove pump cover screws and pump cover. Mark gears so they may be reassembled with same tooth indexed. Remove idler gear, drive gear and shaft from pump housing.
2. Remove pressure regulator valve retaining pin from pump cover. Remove regulator valve components from pump cover. Note order of removal. DO NOT disassemble pick-up screen and pipe. Screen and pipe are serviced only as an assembly with pump.

1. Inspect pump body and cover for cracks or excessive wear. Inspect pump gears for damage or wear. Check drive gear shaft for looseness in pump body.
2. Check pressure regulator valve for fit in bore. Inspect inlet tube and screen assembly for damage. Replace entire pump assembly if damaged.

Reassembly & Installation

1. Install pump gears into pump body with marked gear teeth indexed. Reassemble remaining components in reverse order of disassembly. Place pump and extension shaft inside oil pan. Position oil pan in place.
2. Install pump and extension shaft on engine, ensuring slot on top of extension shaft engages with drive tang on end of pump drive or vacuum pump. Tighten mounting bolt to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/forward-control-p30/1985-1999/remont/mechanical/#62l-v8-diesel-vin-j__torque-specifications) . Install oil pan.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

GENERAL ENGINE SPECIFICATIONS

GENERAL ENGINE SPECIFICATIONS

CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS SPECS

CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS SPECS

CONNECTING RODS SPECIFICATIONS

CONNECTING RODS SPECIFICATIONS

PISTONS, PINS & RINGS SPECIFICATIONS

PISTONS, PINS & RINGS SPECIFICATIONS

CYLINDER BLOCK SPECIFICATIONS

CYLINDER BLOCK SPECIFICATIONS

VALVES & VALVE SPRINGS SPECIFICATIONS

VALVES & VALVE SPRINGS SPECIFICATIONS

CYLINDER HEAD SPECIFICATIONS

CYLINDER HEAD SPECIFICATIONS

CAMSHAFT SPECIFICATIONS

CAMSHAFT SPECIFICATIONS

VALVE LIFTERS SPECIFICATIONS

VALVE LIFTERS SPECIFICATIONS

See also:
• ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION
• TORQUE SPECIFICATIONS
• OVERHAUL
• ENGINE SPECIFICATIONS