Buick LaCrosse 2017-2019 3.6L Engine Bolt Torque Specifications & Fastener Values
Buick LaCrosse 2017-2019

Buick LaCrosse 2017-2019 3.6L Engine Bolt Torque Specifications

This page provides detailed torque specifications for various bolts on the 3.6L V6 engine found in the 2017-2019 Buick LaCrosse, including cylinder head bolts, intake manifold bolts, exhaust manifold bolts, and other critical fasteners.

Updated

Important Information

Safety guidelines and reference information for proper torque application

Quick Reference Guide
ft-lbs → Nm
× 1.356
ft-lbs → kg-m
× 0.138
Nm → ft-lbs
× 0.738
in-lbs → ft-lbs
× 0.083

Common Torque Patterns

Star Pattern

Used for wheels and other circular bolt patterns

Star Pattern torque pattern diagram showing proper bolt tightening sequence
Cross Pattern

Used for gaskets and cover plates

Cross Pattern torque pattern diagram showing proper bolt tightening sequence
Sequential Pattern

Used for head bolts and other critical components

Sequential Pattern torque pattern diagram showing proper bolt tightening sequence

Common Mistakes to Avoid

Over-tightening

Exceeding the specified torque value can stretch or break fasteners, damage threads, or crack components.

Prevention:

Always use a calibrated torque wrench and follow specifications exactly.

Incorrect Torque Sequence

Tightening bolts in the wrong order can cause uneven pressure distribution and potential leaks or damage.

Prevention:

Follow the manufacturer's specified torque sequence pattern.

Dirty Threads

Dirt, rust, or old thread locker can affect torque readings and proper fastener tension.

Prevention:

Clean and inspect all threads before assembly. Use new thread locker if specified.

Reusing TTY Bolts

Torque-to-yield bolts are designed to stretch and must not be reused.

Prevention:

Always replace TTY bolts with new ones. They are single-use only.

Dry vs. Lubricated

Not accounting for whether torque specs are for dry or lubricated fasteners can lead to incorrect tension.

Prevention:

Check if specs are for dry or lubricated threads. Use specified lubricant when required.

Recommended Tools

Torque Wrench (1/4" Drive)

Range: 2-25 ft-lbs
Small fasteners, delicate components

Torque Wrench (3/8" Drive)

Range: 10-100 ft-lbs
Most common automotive fasteners

Torque Wrench (1/2" Drive)

Range: 30-250 ft-lbs
Large fasteners, wheels

Angle Gauge

Torque-to-yield (TTY) bolts

Torque Wrench Care

  • Calibrate annually or after 5,000 clicks
  • Store at lowest setting
  • Keep clean and lubricated

Search Specifications

Search by component name, bolt size, or description

Torque Calculator

Convert between different torque units

Cylinder Head

Components related to the cylinder head, including bolts, studs, and associated parts.

1

Cylinder Head Bolts

M12 x 1.75
Important Notes
Cylinder head bolts are torque-to-yield (TTY) and require an additional 90° angle turn after the initial torque. Always use new bolts. Follow a proper tightening sequence from the center outwards, refer to the service manual.
2

Valve Cover Bolts

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Use care, as these bolts are low torque and prone to stripping. Tighten in a crisscross pattern.
3

Rocker Arms/Shafts Bolts

M8 x 1.25
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Torque these bolts evenly, using a sequence, typically from the center outwards.
4

Camshaft Bearing Cap Bolts

M8 x 1.25
Important Notes
Camshaft bearing cap bolts have an initial torque and an angle torque, refer to the service manual. Always follow proper torque sequence and double check angle and torque values.
5

Exhaust Manifold/Headers Bolts

M8 x 1.25
Torque Value
26 ft-lbs (35 N·m)
Important Notes
Tighten in a crisscross pattern from the center outwards. Check for exhaust leaks after installation.
6

Exhaust Manifold Studs

M8 x 1.25
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Tighten in a crisscross pattern, as above for the exhaust manifold bolts

Engine Block

Components directly attached to or within the engine block.

1

Main Bearing Bolts

M12 x 1.5
Torque Value
37 ft-lbs (50 N·m)
Important Notes
Tighten in a proper sequence, from the center outwards. Check for proper torque value before engine operation
2

Connecting Rod Nuts

M9 x 1.0
Important Notes
Connecting rod nuts require an additional 60° angle turn after the initial torque. Always use new nuts and check torque values before operation.
3

Oil Pan Bolts

M6 x 1.0
Torque Value
8.8 ft-lbs (12 N·m)
Important Notes
Use care, as these bolts are low torque and prone to stripping. Use a crisscross pattern.
4

Timing Belt/Chain Tensioner Bolt

M10 x 1.5
Torque Value
28 ft-lbs (38 N·m)
Important Notes
This is critical for proper timing belt or chain tension.
5

Oil Filter Housing Bolt

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Ensure proper sealing of the oil filter housing to prevent oil leaks.
6

Oil Drain Plug Bolt

M14 x 1.5
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Use a new crush washer or sealing washer to prevent oil leaks.
7

Knock Sensor Bolt

M8 x 1.25
Torque Value
15 ft-lbs (20 N·m)
Important Notes
This is critical for accurate knock sensor readings. Torque value is estimated, refer to service manual
8

Water Pump Bolts

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Ensure proper sealing of the water pump to prevent coolant leaks

Intake System

Components related to the air intake of the engine.

1

Throttle Body Bolts

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Use care, as these bolts are low torque and prone to stripping. Ensure no vacuum leaks.
2

Intake Manifold Bolts

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Tighten in a crisscross pattern from the center outwards. Ensure no vacuum leaks.
3

Intake Manifold Plenum Bolts

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
These bolts are low torque, use care. Ensure proper sealing to prevent vacuum leaks. Torque value is estimated, refer to service manual
4

EGR Valve Bolts

M6 x 1.0
Torque Value
8.8 ft-lbs (12 N·m)
Important Notes
Use care, as these bolts are low torque. Ensure proper sealing.

Fuel System

Components related to the fuel delivery of the engine.

1

Fuel Rail Bolts

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Use care, as these bolts are low torque and prone to stripping. Ensure no fuel leaks.
2

Fuel Injector Bolts

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Use care, as these bolts are low torque. Some models may use clips rather than bolts.
3

Fuel Filter Bolt/Nut

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Ensure proper sealing and prevent fuel leaks

Ignition System

Components that are directly related to the ignition of the engine.

1

Spark Plugs

M14 x 1.25
Torque Value
15 ft-lbs (20 N·m)
Important Notes
Proper torque ensures a good seal for combustion and electrical conductivity. Over or under torquing can cause damage to the plug or cylinder head.
2

Ignition Coil Bolt

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Use care, as these bolts are low torque and prone to stripping.

Cooling System

Components directly related to engine cooling.

1

Water Pump Pulley Bolts

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Ensure proper power transfer to the water pump and prevent pulley from coming loose.
2

Thermostat Housing Bolts

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Use care, as these bolts are low torque and prone to stripping. Proper torque is critical to prevent coolant leaks.
3

Engine Coolant Temperature Sensor Bolt

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Use care, as these bolts are low torque. Ensure proper sealing.

Accessories

Components related to the accessory drive belt system.

1

Crankshaft Pulley/Harmonic Balancer Bolt

M14 x 1.5
Important Notes
Some models may use an angle torque. Refer to the service manual.
2

Serpentine/Accessory Drive Belt Tensioner Bolt

M10 x 1.5
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Ensure proper belt tension, as this is critical to prevent belt slippage.
3

Drive Belt Idler Pulley Bolt

M10 x 1.5
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Ensure proper belt alignment

Sensors

Components related to engine sensors.

1

Camshaft Position Sensor Bolt

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Use care, as these bolts are low torque and prone to stripping.
2

Crankshaft Position Sensor Bolt

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Use care, as these bolts are low torque and prone to stripping.
3

Oil Pressure Sensor Bolt

M6 x 1.0
Torque Value
8.8 ft-lbs (12 N·m)
Important Notes
Use care, as these bolts are low torque and prone to stripping. Ensure no oil leaks.

Other

Fasteners not in other categories, such as Flywheel bolts.

1

Flywheel Bolts

M10 x 1.5
Torque Value
46 ft-lbs (62 N·m)
Important Notes
Proper torque is essential to prevent the flywheel from coming loose.

Troubleshooting Guide

Common issues, diagnostic steps, and prevention guidelines

Common Issues

Bolt stretching, stripped threads, uneven torque patterns

Loose Components

Symptoms:
  • Rattling or vibration noises
  • Visible movement in components
  • Uneven panel gaps
Solutions:
  • Clean threads and mounting surfaces
  • Replace damaged fasteners
  • Apply proper torque in sequence
  • Use thread locker if specified

Stripped Fasteners

Symptoms:
  • Unable to achieve proper torque
  • Fastener spins freely
  • Visible thread damage
Solutions:
  • Use thread repair kit if appropriate
  • Install thread insert (HeliCoil)
  • Replace component if threaded hole is damaged
  • Upgrade to higher grade fastener if recommended

Overtightened Components

Symptoms:
  • Cracked or deformed parts
  • Broken fasteners
  • Compressed gaskets or seals
Solutions:
  • Replace damaged components
  • Use new fasteners
  • Follow proper torque sequence
  • Verify correct torque specifications

Diagnostic Steps

Visual inspection, torque verification, thread assessment

1

Visual Inspection

Inspect the affected area for any visible signs of damage or wear

  • Check for cracks or deformation
  • Look for signs of excessive wear
  • Verify proper fastener installation
2

Torque Verification

Verify the torque applied to the fasteners

  • Check the torque wrench calibration
  • Verify the torque specification
  • Compare the applied torque to the specification
3

Thread Assessment

Assess the condition of the threads

  • Check for signs of thread damage
  • Verify the thread type and size
  • Check for proper thread engagement

Prevention Guidelines

Best practices, maintenance tips, tool care

Best Practices

  • Always follow the recommended torque specification
  • Use the correct type and size of fasteners
  • Verify the torque wrench calibration regularly

Maintenance Tips

  • Regularly inspect the affected area for signs of wear or damage
  • Replace damaged or worn-out components promptly
  • Keep the work area clean and organized

Tool Care

  • Regularly clean and maintain the torque wrench
  • Store the torque wrench in a dry and secure location
  • Verify the torque wrench calibration before each use

Frequently Asked Questions

Find answers to common questions about torque specifications

Q1

Why are torque specifications important?

Torque specifications ensure fasteners are tightened sufficiently to prevent loosening during operation while avoiding damage to components from over-tightening. For example, if you over-torque a cylinder head bolt on the 3.6L engine, you risk damaging the head, gasket, or bolt itself, potentially leading to coolant leaks or head gasket failure. Under-torquing can cause leaks and loose components.

Q2

What happens if I don't use a torque wrench?

Without a torque wrench, it’s very difficult to achieve proper fastener tightness. Guessing or 'going by feel' can easily lead to under- or over-torquing. Over-tightening can damage threads, stretch bolts, and deform components, while under-tightening can cause leaks and component failure due to vibration or stress. Imagine replacing the intake manifold on your 3.6L - if the bolts are not properly torqued, you risk vacuum leaks that will cause the engine to run poorly.

Q3

Can I reuse old bolts?

Some bolts, particularly those that are torque-to-yield (TTY), are designed for one-time use and should not be reused. Cylinder head bolts on the 3.6L engine are typically torque-to-yield. Reusing a TTY bolt can lead to inaccurate clamping force and potential failure. Other bolts may be reusable but should be inspected for damage or stretching before reinstallation. A good rule of thumb is to follow the service manual guidelines, and when in doubt, replace the bolt.

Q4

What does 'torque-to-yield' mean?

Torque-to-yield (TTY) bolts are designed to stretch when tightened to a specific torque and angle. This stretching creates a more consistent clamping force. They should be replaced each time they are loosened because they have undergone deformation. A common example is the cylinder head bolts. TTY bolts should never be reused.

Q5

Where can I find the torque specifications for all components on the 3.6L engine?

The most accurate source for torque specifications is the official service manual for the 2017-2019 Buick Lacrosse with the 3.6L engine. These manuals are available through authorized dealers, professional service databases, and some aftermarket auto parts sources. Always verify the specifications against the specific component you are working on.

Environmental Considerations

Temperature, humidity, and seasonal effects on torque specifications

Temperature Effects

Includes: High Heat, Cold Weather, Thermal Cycling

Temperature can significantly impact torque values and fastener behavior

Cold Weather

Effects:
  • Increased material brittleness
  • Higher torque required due to thread contraction
  • Reduced thread lubricant effectiveness
Recommendations:
  • Allow components to warm to room temperature when possible
  • Consider using winter-grade thread lubricants
  • Check torque values more frequently during winter months

Hot Weather

Effects:
  • Thermal expansion of components
  • Decreased friction in threads
  • Accelerated lubricant breakdown
Recommendations:
  • Check torque when components are at normal operating temperature
  • Use temperature-resistant thread lockers
  • Consider re-torquing after heat cycles

Humidity and Corrosion

Covers: Rust Prevention, Salt Exposure, Moisture Control

Moisture and corrosion can affect fastener integrity and torque values

High Humidity

Effects:
  • Accelerated corrosion formation
  • Reduced friction coefficient
  • Potential thread seizing
Prevention:
  • Use corrosion-resistant fasteners
  • Apply appropriate anti-seize compounds
  • Maintain proper protective coatings

Salt Exposure

Effects:
  • Rapid corrosion development
  • Thread damage
  • Seized fasteners
Prevention:
  • Regular underbody washing
  • Use of sacrificial anodes where appropriate
  • Application of protective coatings

Seasonal Maintenance

Spring, Summer, Fall, and Winter maintenance schedules

Spring

  • Inspect for winter damage
  • Clean and protect exposed fasteners
  • Check torque on critical components

Summer

  • Monitor heat-affected components
  • Check expansion-related loosening
  • Inspect cooling system mounts

Fall

  • Prepare for winter conditions
  • Apply corrosion protection
  • Verify all fasteners are properly torqued

Winter

  • More frequent inspection of critical fasteners
  • Check for salt damage
  • Monitor suspension component torque

Related Resources

Tools, service procedures, and technical bulletins

Recommended Tools

Torque Wrench (1/2 inch drive)

A calibrated torque wrench is essential for accurately tightening bolts to specified torque values. A 1/2-inch drive is commonly used for engine components.

  • Wide torque range coverage
  • Audible click for accurate torque application
  • Durable construction
Learn more

Torque Wrench (3/8 inch drive)

A smaller 3/8-inch drive torque wrench for bolts and fasteners with smaller torque specifications.

  • Lower torque range for smaller fasteners
  • Precise and reliable torque application
  • Ergonomic handle for comfortable use
Learn more

Socket Set (Metric)

A comprehensive metric socket set is needed to fit the different sizes of bolts on the 3.6L engine.

  • Various sizes to fit all engine bolts
  • Durable construction for heavy use
  • Clearly marked sizes
Learn more

Extension Bars

Extension bars will aid in reaching recessed bolts or fasteners.

  • Variety of lengths
  • Durable
  • Allows access to hard to reach areas
Learn more

Universal Joint

Universal joints allow for sockets to be used at an angle.

  • Allows for socket usage at angles
  • Durable
  • Smooth movement
Learn more

Thread Locker (Medium Strength)

Medium-strength threadlocker helps prevent bolts from loosening due to vibration and temperature variations.

  • Prevents bolt loosening
  • Medium strength for easy removal
  • Heat resistant
Learn more
Service Procedures

Intake Manifold Installation

Proper installation of the intake manifold on the 3.6L engine requires specific torque values to ensure a proper seal and avoid leaks.

  • Clean the mating surfaces of the intake manifold and cylinder heads.
  • Position the intake manifold onto the engine.
  • Install the intake manifold bolts, starting at the center and working outwards in a criss-cross pattern.
  • Torque the bolts to the specified value (usually around 89 in-lbs) using a torque wrench.
  • Double check all bolts are torqued to specification.
  • Reconnect all electrical and vacuum connections.
View full procedure

Cylinder Head Installation

When installing cylinder heads, specific torque and angle tightening sequences are crucial for maintaining proper gasket compression and sealing.

  • Clean the cylinder head and engine block mating surfaces.
  • Place the cylinder head gasket on the block.
  • Carefully position the cylinder head on the engine.
  • Install the cylinder head bolts finger tight.
  • Torque the bolts to the first stage specified torque using a torque wrench.
  • Continue tightening bolts in the correct sequence as specified and torquing to second stage of value.
  • Use an angle gauge to tighten the bolts the specified degrees using the correct sequence.
  • Verify all bolts are torqued to specification.
View full procedure

Oil Pan Installation

Proper oil pan installation ensures that there are no leaks.

  • Clean the oil pan and engine block mating surfaces.
  • Apply sealant to the oil pan mating surface as specified.
  • Install the oil pan and thread bolts in finger tight.
  • Tighten the oil pan bolts using a torque wrench and the correct sequence.
  • Torque all bolts to the specified value.
  • Double check that the correct sequence was followed and that all bolts are torqued to spec.
View full procedure

Connecting Rod Cap Installation

Correct torque specification for connecting rod cap bolts is crucial to avoid engine failure.

  • Ensure the bearing shells are correctly installed into the connecting rod and cap.
  • Apply engine oil to the connecting rod bolts.
  • Install the connecting rod cap and thread bolts in by hand
  • Tighten the bolts to the first stage torque specification using a torque wrench.
  • Use an angle gauge to tighten the bolts the specified degrees.
  • Verify all bolts are torqued to specification.
View full procedure
Technical Service Bulletins

Engine Oil Leakage from Oil Pan

2018-05-15

Some 2017-2019 Buick Lacrosse vehicles with the 3.6L engine may experience oil leaks from the oil pan due to improper sealant application or bolt torque.

2017-2019

Resolution: Inspect the oil pan mating surface for any damage or irregularities. Ensure proper cleaning of the surface and use the correct sealant, applying a bead of 3-5mm in the correct pattern. Install the oil pan and torque bolts to the specified value in the correct sequence to avoid over or under tightening and to ensure proper sealant compression.

Cylinder Head Bolt Torsional Variation

2019-01-20

Reports indicate inconsistent bolt torque on cylinder heads leading to premature gasket failure on certain 3.6L engines.

2017-2019

Resolution: Always use new cylinder head bolts when removing and replacing the cylinder head. Ensure the bolts are torqued in the specified order and to the correct torque and angle specifications. Double check torque and angle specifications.

Intake Manifold Gasket Leak

2017-12-10

Reports of vacuum leaks after intake manifold re-installation are likely due to improper torque or damage to intake manifold gasket on 3.6l engines.

2017-2018

Resolution: Inspect intake manifold for any damage and replace if necessary. When installing, torque the bolts to spec and double check all intake manifold bolts for proper torque. Replace intake manifold gasket if leak was present prior to reinstallation.

About the Author

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Alan Montanye - Automotive Technical Specialist
ASE

Alan Montanye

Automotive Technical Specialist

ASE Master Certified Technician with over a decade of hands-on experience in automotive repair and diagnostics.

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Technical Information
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