W-BODYTECH • ENGINE TECHNICAL LIBRARY

W-Body Engine Torque Specifications

Internal-engine and major engine-service fastener specifications for the factory engine families used across GM W-Body production. Choose the exact engine, RPO and model year before using any torque procedure.

1988–2016 W-Body17 Engine GroupsTorque + Angle ProceduresRPO / Year Sensitive

THE MOST IMPORTANT RULE

Torque specifications belong to an exact engine and service procedure.

W-Body production spans unrelated engine architectures and multiple fastener revisions. A torque value without the correct RPO, model year, sequence, lubricant or angle step can be wrong even when the displacement looks the same.

Identify VIN + RPODo not work from displacement alone

Use torque angle correctlyDegrees are part of the specification

Replace single-use boltsTTY fasteners must be replaced where specified

Follow the sequenceHead, main and intake patterns matter

ENGINE DIRECTORY

Find Your W-Body Engine

Search by displacement, RPO, engine family or vehicle, or filter by engine architecture.

17 engine groups shown

EARLY FOUR-CYLINDER

2.5L LR8 Iron Duke

1990–1992 Chevrolet Lumina • LR8 / Tech IV

VERIFY RPO + YEAR

The 2.5L head-bolt procedure changed during this engine family’s production. Verify the exact model-year service procedure before final assembly.

Component	Torque Procedure	Service Note
Cylinder head bolts	18 lb-ft first pass; 22 lb-ft second pass except No. 9 at 30 lb-ft; then +120° except No. 9 +90°	Torque-angle procedure; sequence required
Main bearing cap bolts	70 lb-ft	Use correct cap order and clean threads
Throttle body to intake	18 lb-ft	Passenger-car LR8 service value

EARLY FOUR-CYLINDER

2.2L LN2

1993 Chevrolet Lumina • LN2

VERIFY RPO + YEAR

LN2 service data is consistent across early car applications, but the exact 1993 W-body manual remains the controlling reference.

Component	Torque Procedure	Service Note
Cylinder head bolts — long	46 lb-ft + 90°	Tighten in sequence
Cylinder head bolts — short	43 lb-ft + 90°	Tighten in sequence
Main bearing cap bolts	70 lb-ft
Connecting rod nuts	38 lb-ft
Camshaft sprocket bolt	96 lb-ft
Lower intake manifold to head	24 lb-ft	Tighten in sequence
Upper intake to lower intake	22 lb-ft
Rocker arm nuts	22 lb-ft
Oil pump bolts	32 lb-ft
Oil pump cover bolts	89 lb-in
Oil pan nuts / bolts	89 lb-in
Water pump bolts	18 lb-ft
Valve cover bolts	89 lb-in

EARLY FOUR-CYLINDER

2.3L Quad 4

Early Pontiac Grand Prix / Oldsmobile Cutlass Supreme • Quad 4

VERIFY RPO + YEAR

Quad 4 cylinder-head fasteners use different initial torque values for the long and short bolts before the angle pass.

Component	Torque Procedure	Service Note
Cylinder head bolts 1–8	30 lb-ft + 90°	Long bolts; factory sequence required
Cylinder head bolts 9–10	26 lb-ft + 90°	Short bolts; factory sequence required
Main bearing cap bolts	15 lb-ft + 90°
Connecting rod nuts	18 lb-ft + 80°
Camshaft housing / carrier bolts	11 lb-ft + 90°
Exhaust manifold nuts	31 lb-ft
Exhaust manifold studs	106 lb-in

60° V6

2.8L V6

Early W1 applications • LB6 / related transverse 60° V6

VERIFY RPO + YEAR

Early 2.8L procedures vary by model year. Use the exact W-body service manual for final assembly.

Component	Torque Procedure	Service Note
Cylinder head bolts	33 lb-ft + 90°	Late transverse service procedure; sequence required
Intake plenum bolts	16 lb-ft
Throttle body to plenum	18 lb-ft
Fuel rail to intake	8 lb-ft

60° V6

3.1L LH0 / LG5 Turbo

Early W1 applications • LH0 naturally aspirated / LG5 Turbo Grand Prix

VERIFY RPO + YEAR

The turbo LG5 shares the basic 60° V6 architecture but uses application-specific hardware in several areas. Confirm the exact RPO.

Component	Torque Procedure	Service Note
Cylinder head bolts	33 lb-ft + 90°	Use sealant where specified; sequence required
Rocker arm nuts	19 lb-ft
Exhaust manifold bolts	21 lb-ft
Exhaust crossover nuts	18 lb-ft
Camshaft sprocket bolt	21 lb-ft
Lower intake — center bolt	15 lb-ft
Lower intake manifold bolts	19 lb-ft
Upper intake / plenum	88 lb-in	Center-out tightening recommended

DOHC 60° V6

3.4L LQ1 DOHC

1991–1997 W-body applications • LQ1 Twin Dual Cam

VERIFY RPO + YEAR

The LQ1 has its own DOHC carrier, intermediate-shaft and timing-drive fasteners. Do not use pushrod 3.4L or 3400 specifications.

Component	Torque Procedure	Service Note
Cylinder head bolts	44 lb-ft + 90°	Sequence required
Main bearing cap bolts / studs	37 lb-ft + 75°
Connecting rod cap nuts	15 lb-ft + 75°
Camshaft drive sprocket bolt	96 lb-ft
Intermediate shaft belt sprocket bolt	96 lb-ft
Camshaft housing to cylinder head	20 lb-ft
Crankshaft balancer mounting bolt	79 lb-ft
Crank pulley to balancer bolts	44 lb-ft
Flywheel bolts	60 lb-ft
Oil pump mounting bolt	40 lb-ft
Oil pump drive bolt	27 lb-ft
Oil pump cover bolts	89 lb-in
Water pump pulley bolts	18 lb-ft

GEN III 60° V6

3100 V6 — L82 / LG8

W1 / W2 applications • 3100 SFI

VERIFY RPO + YEAR

GM issued revised torque procedures for the 3100/3400 family. Later service information supersedes older generic values.

Component	Torque Procedure	Service Note
Cylinder head bolts	44 lb-ft + 95°	Use NEW bolts; revised GM procedure
Main bearing cap bolts	37 lb-ft + 77°
Rocker arm bolts	124 lb-in + 30°	Revised procedure
Lower intake — initial pass	62 lb-in	All lower-intake bolts
Lower intake — vertical bolts	115 lb-in final	Four vertical bolts
Lower intake — diagonal corner bolts	18 lb-ft final	Corner bolts
Upper intake manifold	18 lb-ft
Front / timing cover — large and medium	41 lb-ft	Application dependent
Front / timing cover — small	20 lb-ft	Application dependent

GEN III 60° V6

3400 V6 — LA1

W2 applications • 3400 SFI

VERIFY RPO + YEAR

The LA1 shares many procedures with the later 3100, but component and model-year differences still matter.

Component	Torque Procedure	Service Note
Cylinder head bolts	44 lb-ft + 95°	Use NEW bolts; revised GM procedure
Main bearing cap bolts	37 lb-ft + 77°
Connecting rod cap nuts	15 lb-ft + 75°
Camshaft sprocket bolt	103 lb-ft
Crankshaft balancer bolt	52 lb-ft + 72°
Rocker arm bolts	124 lb-in + 30°	Revised procedure
Lower intake — initial pass	62 lb-in	All lower-intake bolts
Lower intake — vertical bolts	115 lb-in final	Four vertical bolts
Lower intake — diagonal corner bolts	18 lb-ft final	Corner bolts
Upper intake manifold	18 lb-ft
Front / timing cover — large and medium	41 lb-ft
Front / timing cover — small	20 lb-ft

BUICK 3800

3800 Series I

Early W-body 3.8L applications • LN3 / L27

VERIFY RPO + YEAR

Series I procedures changed during production. Head and intake procedures must be matched to model year.

Component	Torque Procedure	Service Note
Cylinder head bolts — early procedure	35 lb-ft + 130° + 30°	Year-sensitive; use exact service information
Upper intake to lower intake — 1991–1992	21 lb-ft	L27 revised service information
Lower intake to block — 1991–1992	89 lb-in	L27 revised service information
Upper intake to lower intake — 1993–1995	11 lb-ft	L27 revised service information
Lower intake to block — 1993–1995	11 lb-ft	L27 revised service information

BUICK 3800

3800 Series II — L36 / L67

Naturally aspirated L36 / supercharged L67

VERIFY RPO + YEAR

Torque-plus-angle values are intentional. Do not replace them with an estimated final ft-lb number.

Component	Torque Procedure	Service Note
Cylinder head bolts	37 lb-ft + 120°	Use NEW bolts; sequence required
Main bearing cap bolts	30 lb-ft + 110°
Main cap side bolts	11 lb-ft + 45°
Connecting rod bolts	20 lb-ft + 50°
Rocker arm bolts	11 lb-ft + 90°	Use NEW bolts
Camshaft sprocket bolt	74 lb-ft + 90°
Camshaft thrust plate bolts	11 lb-ft
Crankshaft balancer bolt	111 lb-ft + 76°
Lower intake manifold bolts	11 lb-ft
Upper intake manifold	89 lb-in	L36
Supercharger bolts / studs	17 lb-ft	L67
Supercharger oil plug	89 lb-in	L67
Exhaust manifold bolts	22 lb-ft
Timing chain damper bolts	16 lb-ft
Front cover bolts	15 lb-ft + 40°
Oil pan bolts	125 lb-in
Oil pump cover bolts	98 lb-in
Valve cover bolts	89 lb-in

BUICK 3800

3800 Series III — L26 / L32

Naturally aspirated L26 / supercharged L32

VERIFY RPO + YEAR

Series III retained much of the late 3800 short-block fastener strategy, but intake and supercharger hardware differs by RPO.

Component	Torque Procedure	Service Note
Cylinder head bolts	37 lb-ft + 120°	Use NEW bolts; sequence required
Main bearing cap bolts	30 lb-ft + 110°
Main cap side bolts	11 lb-ft + 45°
Connecting rod bolts	20 lb-ft + 50°	Verify exact model year
Rocker arm bolts	11 lb-ft + 90°	Use NEW bolts

SHORTSTAR DOHC

3.5L LX5 Shortstar

1999–2002 Oldsmobile Intrigue • VIN H

VERIFY RPO + YEAR

The LX5 is unrelated to the later 3.5L High Value pushrod engine. Keep its DOHC procedures separate.

Component	Torque Procedure	Service Note
Cylinder head bolts — M11	30 lb-ft + 100° + 100°	Use NEW M11 bolts
Cylinder head bolts — M6	106 lb-in	Long / short auxiliary head bolts
Lower crankcase bolts	15 lb-ft + 70°	Bolts 1–16 in sequence
Lower crankcase perimeter bolts	22 lb-ft	Bolts 1–9 in sequence
Connecting rod bolts — checking pass	22 lb-ft, then back off to zero
Connecting rod bolts — final	18 lb-ft + 110°
Intake manifold bolts	62 lb-in	Center-out circular pattern
Exhaust manifold to head	18 lb-ft	Stud and nut assembly
Oil pump pickup / screen bolt	89 lb-in

HIGH VALUE V6

3.5L High Value — LZE / LZ4

2006–2011-era W-body applications

VERIFY RPO + YEAR

The 3.5L High Value cylinder-head and crankshaft procedures changed during production. Early and late values are shown separately.

Component	Torque Procedure	Service Note
Cylinder head bolts — 2006–2008 service	44 lb-ft + 95°	Use exact RPO/year procedure
Cylinder head bolts — later service	44 lb-ft + 140°	Late documented procedure; verify exact RPO/year
Main bearing cap bolts	37 lb-ft + 77°
Connecting rod bolts	18 lb-ft + 110°
Crankshaft balancer — later service	92 lb-ft + 130°	Year-sensitive
Lower intake — initial pass	62 lb-in
Lower intake — center bolts final	115 lb-in
Lower intake — corner bolts final	18 lb-ft
Upper intake manifold	18 lb-ft
Exhaust manifold bolts	15 lb-ft
Oil pump mounting bolts	30 lb-ft
Oil pump drive bolt	27 lb-ft
Oil pump cover bolts	89 lb-in
Water pump bolts	18 lb-ft

HIGH VALUE V6

3.9L High Value — LZ9 / LZG

2006–2011-era W-body applications

VERIFY RPO + YEAR

The 3.9L received major service-procedure revisions. Crank balancer and cylinder-head angle values are especially year-sensitive.

Component	Torque Procedure	Service Note
Cylinder head bolts — 2006-era service	44 lb-ft + 95°	Verify exact RPO/year
Cylinder head bolts — 2009-era service	44 lb-ft + 140°	Verify exact RPO/year
Main bearing cap bolts	37 lb-ft + 77°
Connecting rod bolts	18 lb-ft + 110°
Crankshaft balancer — 2006-era	52 lb-ft + 70°	Year-sensitive
Crankshaft balancer — 2009-era	92 lb-ft + 130°	Year-sensitive
Lower intake — center bolts	10 lb-ft first pass; 15 lb-ft final
Lower intake — corner bolts	10 lb-ft first pass; 18 lb-ft final
Upper intake manifold	18 lb-ft
Exhaust manifold bolts	15 lb-ft
Oil pump mounting bolts	30 lb-ft
Oil pump drive bolt	27 lb-ft
Oil pump cover bolts	89 lb-in
Water pump bolts	18 lb-ft

HIGH FEATURE V6

3.6L LY7 DOHC

Buick LaCrosse / Allure W-body applications • LY7

VERIFY RPO + YEAR

The LY7 uses multiple main-cap bolt groups and two different cylinder-head bolt sizes. Follow the exact sequence and replace fasteners where specified.

Component	Torque Procedure	Service Note
Cylinder head bolts — M11	33 lb-ft + 120°	Use NEW M11 bolts
Cylinder head bolts — M8	10 lb-ft + 60°
Main bearing bolts — inboard	15 lb-ft + 80°
Main bearing bolts — outboard	11 lb-ft + 110°
Main bearing side bolts	22 lb-ft + 60°	Short and long side bolts
Connecting rod bolts — checking pass	22 lb-ft, then back off to zero	Use old bolts only for clearance checking
Connecting rod bolts — final	18 lb-ft + 110°	Use NEW bolts
Crankshaft balancer bolt	74 lb-ft + 150°
Camshaft cap bolts	89 lb-in
Intake manifold bolts	17 lb-ft
Exhaust manifold bolts	15 lb-ft
Intermediate / idler sprocket bolt	43 lb-ft
Front cover bolts	17 lb-ft
Timing-chain tensioner bolts	17 lb-ft

HIGH FEATURE V6

3.6L LFX DOHC

2012–2016 Chevrolet Impala / Impala Limited W-body • LFX

VERIFY RPO + YEAR

The LFX head bolts are torque-to-yield / single-use fasteners. Do not reuse them.

Component	Torque Procedure	Service Note
Cylinder head bolts — M11	22 lb-ft + 150°	Use NEW bolts; sequence required
Cylinder head bolts — M8	11 lb-ft + 75°	Use NEW bolts
Crankshaft balancer bolt	74 lb-ft + 150°	Use exact service procedure
Camshaft cap bolts	89 lb-in

GEN IV SMALL-BLOCK

5.3L LS4 V8

Grand Prix GXP • Impala SS • Monte Carlo SS • LaCrosse Super

VERIFY RPO + YEAR

The LS4 uses Gen IV small-block architecture in a transverse W-body package. Use LS4-specific service information rather than a generic longitudinal LS chart.

Component	Torque Procedure	Service Note
Cylinder head bolts — M11	22 lb-ft + 90° + 70°	Use NEW bolts; sequence required
Cylinder head bolts — M8	22 lb-ft
Main cap bolts — M10	15 lb-ft + 80°
Main cap studs — M10	15 lb-ft + 51°
Main cap cross / M8 bolts	18 lb-ft
Connecting rod bolts	15 lb-ft + 85°
Rocker arm bolts	22 lb-ft	Tighten by cylinder position procedure
Intake manifold — first pass	44 lb-in
Intake manifold — final pass	89 lb-in
Flexplate bolts — pass 1	15 lb-ft
Flexplate bolts — pass 2	37 lb-ft
Flexplate bolts — final	74 lb-ft
Oil pump to block	18 lb-ft
Oil pump cover bolts	106 lb-in
Exhaust manifold — first pass	11 lb-ft
Exhaust manifold — final pass	15 lb-ft
Water pump bolts	11 lb-ft

BEFORE FINAL ASSEMBLY

Do not convert torque-angle procedures into a guessed final torque.

Fastener clamp load depends on thread condition, lubricant or sealer, bolt design, tightening sequence and the specified angle. When a procedure calls for new bolts, use new bolts.

Clean blind holesFluid or debris can create false torque or damage the block.

Use the specified lubricantDry, oiled and pre-coated fasteners do not produce the same clamp load.

Use an angle gaugeTorque-plus-angle values require accurate rotation after the initial pass.

W-BODYTECH COMMUNITY

Working on a Specific Engine?

Use the exact RPO, model year and vehicle when asking for verification. A 3.5L LX5, 3.5L High Value, 3.6L High Feature and 3800 are completely different engine families.

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W-Body Engine Torque Specifications

Torque specifications belong to an exact engine and service procedure.

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Do not convert torque-angle procedures into a guessed final torque.

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