4.1l v6 - VIN [4] Buick Regal II

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 may be identified from the Vehicle Identification Number (VIN) stamped on a metal tab located on top of instrument panel at lower left of windshield. The number may also be found on left rear of engine block at flywheel housing. The VIN number contains 17 digits. The 8th digit identifies the engine and the 10th digit establishes the model year.

ENGINE IDENTIFICATION CODES

TROUBLE SHOOTING

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

ENGINE

See the ENGINE REMOVAL article in this section.

Scheme 52

1. Disconnect battery, remove air cleaner and drain cooling system. Disconnect upper radiator hose and heater hose. Disconnect accelerator, downshift or throttle valve cables at carburetor and bracket at manifold.
2. Disconnect cruise control chain if equipped. Remove booster vacuum line and fuel line at carburetor. Disconnect transmission vacuum modulator line if equipped. (Scheme 52): Intake Manifold Tightening Sequence Install rubber seals on front and rear rails on cylinder block.
3. Disconnect idle speed control leads. Remove distributor wires and temperature sending unit lead. Disconnect vacuum hoses from distributor and coolant by-pass hose at manifold.
4. Remove distributor cap and rotor to gain access to intake manifold Torx head bolt. Remove Torx head bolt. Remove spark plug wires and accelerator linkage springs. Remove A/C compressor top bracket if equipped. Remove intake manifold.

Installation

1. Install new intake manifold gaskets and position new rubber seals on front and rear rails on cylinder block. Make sure pointed end of seal fits tight against block and head.
2. Apply RTV sealer or equivalent to ends of seals. Install intake manifold and bolts. Tighten in sequence shown in Fig. (Scheme 52). Reverse removal procedure to complete installation.

EXHAUST MANIFOLD

Raise and support vehicle on stands. Remove crossover pipe. Disconnect EFE hose from left side of engine. Remove exhaust manifold. Install manifold by reversing removal procedure.

Removal

1. On vehicles equipped with AIR, disconnect rubber hosing at injection tubing check valve. Disconnect battery cable and remove intake manifold. When removing right cylinder head, remove alternator belts and wires.
2. If equipped with A/C, remove compressor from mounting bracket and position out of way. Remove alternator with mounting bracket. When removing left cylinder head, remove oil dipstick and power steering pump with bracket and position out of way.
3. Disconnect spark plug wires. Remove exhaust manifold bolts from head being removed. Remove rocker arm cover and rocker arm shaft assembly. Remove push rods and mark for reinstallation in same location. Remove cylinder head bolts and remove cylinder head.

1. Ensure mating surfaces and bolt holes are clean. Position new head gasket on block with part number down, facing cylinder block.
2. Position head on block. Coat head bolts with heavy duty sealer and install. Tighten head bolts in 3 step sequence. Reverse removal procedure to complete installation. (Scheme 53)

Cylinder Head Tightening Sequence Tighten head bolts in 3 steps. Scheme 53

VALVE ARRANGEMENT

E-I-E-I-I-E (Left side, front to rear).

E-I-I-E-I-E (Right side, front to rear).

VALVE GUIDE SERVICING

1. If stem-to-guide clearance is excessive, replace valve. Some valves with oversize stems are used in production, and can be identified by stamped number on back side of valve head.
2. Valve guide reamers are available in .003", .006" and .010" (.076, .152 and .250 mm) oversize. When reconditioning, always use next oversize reamer and replacement valve.
3. Service valves are available in .003", .006" and .010" (.076, .152 and .250 mm) oversize.

VALVE STEM OIL SEAL SERVICE

1. Valve stem oil seals are installed on intake valves only. Seal is mounted on valve guide. A new seal should be installed whenever valve spring is removed.
2. To install new seals, carefully slide seal over valve stem and push down until it contacts valve guide. Push seal onto guide until seal bottoms against guide.

With cylinder head removed, compress valve spring with a spring compressor and remove valve keepers. Release spring compressor and remove spring retainer and spring. Remove valve stem oil seal from intake valves.

Check valve springs in a valve spring tester and replace as necessary. Install valve stem oil seals on intake valves only. Both intake and exhaust valve springs may be installed with either end up. Reverse removal procedure to complete installation.

ROCKER ARM ASSEMBLY SERVICE

1. With rocker arm removed, remove nylon rocker arm retainers and remove rocker arms from shaft. Inspect shaft and rocker arms for wear, scoring or damage. Replace components as necessary.
2. If rocker arms are being replaced, note that rocker arms are marked left and right. Reverse disassembly procedure to assemble rocker arm. Rocker arms must be installed in correct order on shafts.
3. Center each arm on 1/4" hole in shaft. Install new nylon retainers in holes using a drift punch with at least 1/2" diameter shaft.

Rocker Arm Positioning. Scheme 54

HYDRAULIC VALVE LIFTER ASSEMBLY

1. If hydraulic valve lifters are being removed, mark or identify lifters to ensure that they are installed in original position. Lifters are serviced as complete assemblies only.
2. If lifter is damaged or worn, complete lifter must be replaced. If lifters are disassembled for cleaning and inspection, after reassembly they should be tested using a leakdown rate tester. This system requires no lash adjustment at time of assembly or in service.

Exploded View of Hydraulic Lifter Assembly. Scheme 55

OIL PAN

See OIL PAN REMOVAL article in this section.

1. With cylinder heads removed, check top of cylinder bore for ridge. Remove ridge using ridge reamer. Mark or identify pistons to ensure installation in original position.
2. With oil pan removed, rotate engine until number 1 rod is straight down. Remove rod nuts and cap. Install a short guide in connecting rod hole above crankshaft journal. Install a long connecting rod guide in remaining hole.
3. Turn guides to hold upper bearing shell in place and remove piston and rod assembly. Using long guide, push piston and rod assembly out top of cylinder bore. Follow same procedure to remove remaining piston and rod assemblies. Install rod caps on rods from which they were removed.

Piston Ring Gap Positioning Gap in oil ring rail must be in "up" position. Scheme 56

1. Position rings on piston. Be sure gap in oil ring rails is "up" position toward center of engine and gaps of compression rings are positioned as shown in Fig. (Scheme 56). Clean cylinder bore, pistons and bearing journals.
2. Coat bearing surfaces, piston and cylinder bore with engine oil. Rotate crankshaft until rod journal of piston and rod assembly being installed is straight down.
3. Place bearing insert in rod and install rubber hose over rod bolts. Compress piston rings using ring compressor. Position piston in bore so notch in top of piston is facing toward front of engine.
4. Push piston into bore, guiding rod over crankshaft until bearing is seated against journal. Remove hose and install rod cap and bearing. Tighten rod cap nuts. (Scheme 57)

Piston & Rod Assembly. Scheme 57

FITTING PISTONS

1. Remove piston and rod assembly and clean cylinder bore. Inspect bore for scoring or grooves. Measure cylinder bore for taper or out-of-round.
2. If cylinder taper exceeds .005" (.13 mm) or is out-of-round more than .003" (.07 mm), cylinder must be bored and oversize pistons and rings installed.
3. Measure piston diameter at right angle to piston pin and 1/4" below oil ring groove. If clearance between piston and cylinder is excessive, cylinder must be bored and oversize pistons and rings installed.

FITTING RINGS

1. Position ring in the cylinder bore where it will be used. Push ring down to point in bore where ring wear is not encountered. Use head of piston to position ring squarely in bore.
2. Measure gap between ends of ring using feeler gauge. If gap is incorrect, file ends of rings using smooth file to obtain proper ring gap.

PISTON PIN SERVICE

1. Piston pin is selective press fit in connecting rod. Remove piston pin and separate piston and rod. (Scheme 58)
2. Inspect pin for wear and/or scoring. Check clearance of pin in piston. If clearance is excessive, replace piston and pin assembly. Place piston on rod and install in correct position depending on right or left bank. (Scheme 57)
3. Lubricate pin and press into piston and rod. (Scheme 58) Pin-to-piston fit should be easy finger push fit at 70°F (21°C). Pin-to-rod assembly is a press fit.

Piston Pin Removal & Installation Pin-to-piston fit should be an easy finger push. Scheme 58

CONNECTING ROD BEARING SERVICE

1. Connecting rod bearings consist of 2 halves which are interchangeable in rod and cap. Bearings are not adjustable and must be replaced if clearance becomes excessive.
2. Remove rod cap and inspect bearings for flaking or wear. If bearings are in good condition check for proper clearance on journal. Check connecting rod journal for scoring or grooves. Measure rod journal with micrometer and check journal for out-of-round conditions.
3. Place Plastigage across full width of bearing journal, parallel to crankshaft. Install rod cap and tighten nuts. Remove rod cap and determine amount of clearance by measuring width of compressed Plastigage at widest point.
4. Journal should not exceed .0015" (.038 mm) out-of-round. Check bearing-to-journal clearance using Plastigage method. If clearance exceeds .003" (.076 mm), a selective fit undersize bearing may be installed to obtain correct clearance.
5. If clearance is excessive, crankshaft must be replaced or reconditioned. Measure rod side clearance using feeler gauge.

MAIN BEARING SERVICE

1. Upper crankcase bearing halves are grooved to supply oil to connecting rod bearings. Lower cap bearing halves are not grooved. Upper and lower halves are not interchangeable.
2. Bearings are of precision type and do not require reaming to size. Shims are not provided for adjustment; if bearings are worn, replacement is necessary. Never file ends of bearings flush with parting surfaces of rod and cap or cylinder block and cap.
3. With oil pan, pipe and screen assembly removed, inspect bearings. To remove upper bearing, bearing remover (J-8080) in crankshaft oil hole and rotate crankshaft.
4. Check journal for out-of-round conditions with a micrometer. If journal is out-of-round more than .0015" (.038 mm), crankshaft must be replaced. Check bearing-to-journal clearance using Plastigage method.
5. If clearance exceeds .003" (.076 mm), selective fit undersized bearing may be installed to obtain correct clearance. Insert new bearing and recheck clearance. Undersize shells have a number stamped on outer surface on or near tang to indicate amount of undersize.

THRUST BEARING ALIGNMENT

With thrust bearing cap bolts finger tight, move crankshaft forward and backward, with last movement being forward. Tighten all main bearing cap bolts and rotate crankshaft. Be sure there is no excessive drag. Measure crankshaft end play using a dial indicator.

REAR MAIN BEARING OIL SEAL

Note. Upper half of seal can only be replaced if crankshaft is removed. A seal that leaks can be repaired without being replaced.

OIL SEAL REPAIR

1. With rear main bearing cap removed, insert packing tool against one end of seal in block. Drive old seal into groove, about 1/4" to 3/4" until it is packed tight. Repeat procedure on other end of seal.
2. Measure amount seal was driven up on one side and add 1/16". Remove added length from old rear main bearing cap seal. Cut off same amount from opposite side.
3. Install guide tool (J-21526-1) on cylinder block. Using packing tool, drive cut off piece into groove until packing tool reaches stop on guide tool. Follow same procedure to pack cut off piece into opposite side. Install new seal into rear main bearing cap. Install rear main bearing cap.

OIL SEAL REPLACEMENT

1. With crankshaft removed, pry old seals out of cylinder block and main bearing cap. Position new seal halves in grooves with ends projecting above surface of cap. Roll seals into grooves with hammer handle.
2. Continue rolling seal until ends protrude 1/16" above edge of groove. Cut ends off flush with surface of cap. Lubricate seal contact surface on crankshaft. Install crankshaft and main bearing cap.

MAIN BEARING CAP SIDE SEALS

1. Neoprene seals are placed on sides of bearing cap to prevent leakage. Seals are slightly undersize when newly installed and may leak until neoprene swells in presence of heat and oil. Seals are slightly longer than grooves in cap, but should not be cut off.
2. Soak seals in light oil or kerosene for 1 or 2 minutes before installation. Apply RTV sealer to mating surface of main bearing cap. After seals are installed, force up into cap with end of hammer handle.

1. Drain cooling system. Disconnect upper and lower radiator hoses and heater hose at water pump. Remove drive belts, fan and pulleys. If equipped, loosen AIR. pump and position out of way. Disconnect fuel lines and remove fuel pump. Remove alternator and brackets.
2. Remove distributor. If timing chain and sprockets are not being removed, note position of rotor on distributor for reinstallation. Loosen front clamp on thermostat by-pass hose. Remove harmonic balancer. Remove front engine cover bolts and 2 oil pan-to-front cover attaching bolts and remove front cover and gasket.

1. Oil pump cover should be removed and petroleum jelly packed around oil pump gears whenever front engine cover is removed. Oil pump may lose its prime when front engine cover is removed.
2. Make sure gasket surfaces are clean and use new gasket. Use sealer on bolt threads. Reverse removal procedure to install front engine cover.

Front Cover Assembly Pack oil pump gears with petroleum jelly. Scheme 59

With front engine cover removed, drive seal and shedder out from front to rear of cover, using a drift punch.

Coil new packing around opening so that ends are at top. Using a punch, drive in shedder and stake in place at three points. Size packing by rotating a hammer handle around packing until balancer hub can be inserted through opening.

TIMING CHAIN

Note. Timing chain should be replaced if in and out movement exceeds 1" on slack side of chain.

1. With front cover removed, install harmonic balancer washer and bolt. Rotate engine until timing marks on sprockets are aligned. (Scheme 61) Remove harmonic balancer bolt without disturbing position of sprockets. Remove front oil slinger.
2. Remove camshaft sprocket bolts and alternately pry sprockets on camshaft and crankshaft to enable removal of timing chain and sprockets. Clean all parts thoroughly and replace any part showing wear and/or damage.

Exploded View of Timing Chain Assembly. Scheme 60

1. Make sure No. 1 piston is at TDC and align camshaft and crankshaft timing marks. Install timing chain and sprockets without disturbing alignment of marks. Place oil slinger on crankshaft with large part of cone toward front of engine.
2. Install camshaft sprocket bolts and tighten. Install camshaft thrust spring, button and timing chain damper. Install front cover and attaching bolts and tighten. (Scheme 60)

Timing Chain Sprocket Alignment Rotate engine to align timing marks on sprocket. Scheme 61

1. Remove intake manifold, rocker arm assemblies, push rods and lifters. Mark or identify push rods and lifters to ensure that they are installed in original position.
2. Remove front engine cover and timing chain with sprockets. Slide camshaft forward out of bearing bores, taking care to avoid damaging bearing surfaces.

Thoroughly clean and inspect camshaft. Lubricate journals and camshaft lobes. Insert camshaft taking care not to damage bearings or camshaft lobes. Reverse removal procedures to complete installation.

CAMSHAFT BEARINGS

1. Remove camshaft and crankshaft. Remove inner bearings first. To remove rear bearing, welch plug must be removed. Front bearings may be removed by using a spacer between engine block and puller plate and remove from rear.
2. Install bearings by reversing removal procedures and pulling bearings into place with puller tool. Be sure oil holes in bearing and journal are aligned. Use non-hardening sealer on welch plug before installation.

1. Disconnect negative battery cable and drain cooling system. Disconnect lower radiator hose at water pump. Disconnect heater hose and by-pass at water pump, if equipped.
2. Remove fan assembly and all pulley belts. Remove water pump pulley. Disconnect alternator, A/C compressor and power steering brackets. Remove water pump attaching bolts and remove water pump. Clean all surfaces to ensure proper seal.

1. If installing new water pump, transfer pulley from old pump. Apply thin bead of sealant to water pump sealing surface.
2. While sealant is wet, install water pump and tighten attaching bolts. Install all accessory drive belts and connect negative battery cable.

Note. For information on cooling system capacities and other cooling system components, see appropriate information in COOLING SYSTEM SPECIFICATIONS article in this section.

CRANKCASE CAPACITY

Crankcase capacity is 4 quarts (3.8L) without filter change and 5 quarts (4.7L) with filter change.

NORMAL OIL PRESSURE

Normal oil pressure is 37 psi (2.6 kg/cm 2 ) at 2400 RPM.

PRESSURE REGULATOR VALVE

Pressure regulator valve is located in oil pump and is nonadjustable.

Lubrication is force-feed type. Oil is supplied under full pressure to crankshaft, connecting rods, camshaft bearings and valve lifters. Controlled volume of oil is supplied to rocker arms and push rods. All other moving parts are lubricated by splash or gravity flow.

Engine Oiling System Lubrication is force-feed type. Scheme 62

Disassembly & Removal

1. Remove oil filter. Remove bolts securing oil pump cover assembly to front engine cover. Remove cover assembly and slide pump gears out of pocket.
2. Remove pressure regulator plug, spring and valve from cover assembly. Oil filter by-pass valve and spring are staked in place and should not be removed.

Inspection

1. Thoroughly clean all components and inspect for wear or damage. Check fit of valve in bore. If clearance is excessive, replace valve and/or cover.
2. Position gears in pocket in cover. Place straight edge across gears and using feeler gauge, measure clearance between straight edge and gasket surface. Clearance is .002-.006" (.051-.150 mm). If clearance is below .002" (.051 mm), check gear pocket for wear.

Reassembly & Installation

1. Pack gear pocket with petroleum jelly and insert gears into pocket, making sure jelly is packed into all pockets. Lubricate and install regulator valve in cover.
2. Install spring, gasket and plug. Install new gasket and position cover on oil pump. Tighten cover retaining bolts.

Oil Pump and Components Pack petroleum jelly into gear pockets. Scheme 63

OIL PUMP SPECIFICATIONS

TORQUE SPECIFICATIONS

TIGHTENING SPECIFICATIONS

GENERAL ENGINE SPECIFICATIONS

GENERAL SPECIFICATIONS

VALVE SPECIFICATIONS

VALVE

PISTON/PIN/RING SPECIFICATIONS

PISTONS, PINS, RINGS

BEARING SPECIFICATIONS

CRANKSHAFT MAIN & CONNECTING ROD BEARINGS

VALVE SPRING SPECIFICATIONS

VALVE SPRINGS

CAMSHAFT SPECIFICATIONS

CAMSHAFT

See also:
• ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION
• ENGINE REMOVAL
• COOLING SYSTEM SPECIFICATIONS