Buick LaCrosse 2017-2019 Electrical System Bolt Torque Specifications & Ground Points
Buick LaCrosse 2017-2019

Buick LaCrosse 2017-2019 Electrical System Bolt Torque Specifications

This page provides detailed torque specifications for electrical bolts on the 2017-2019 Buick LaCrosse, including chassis, engine, and body electrical connections.

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

Ignition System

Torque specifications for components within the ignition system, ensuring proper electrical connections and secure mounting.

1

Ignition Coil Mounting Bolt

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Ensures proper electrical contact and secure coil mounting. Torque evenly to prevent damage. If bolts are corroded replace them.

Starting System

Torque specifications for the starter motor, ensuring secure attachment and reliable electrical connections.

1

Starter Motor Mounting Bolts

M10 x 1.5
Torque Value
37 ft-lbs (50 N·m)
Important Notes
Critical for ensuring proper engagement with the flywheel and ground connection. Tighten evenly and gradually.

Charging System

Torque specifications for the alternator, ensuring secure mounting and proper ground connection for effective battery charging.

1

Alternator Mounting Bolts

M10 x 1.5
Torque Value
37 ft-lbs (50 N·m)
Important Notes
Proper torque is vital for alternator grounding. Tighten evenly. If bolts are corroded or damaged replace them.

Battery System

Torque specifications for battery terminal connections, ensuring optimal electrical contact for effective starting power and charging.

1

Battery Terminal Nuts

M8 x 1.25
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Proper torque ensures good electrical contact and minimizes resistance. Avoid over-tightening, which can damage terminals. Clean terminals before installation for optimal results.

Ecm Pcm

Torque specifications for securing the ECM/PCM, crucial for proper functionality and grounding.

1

ECM/PCM Mounting Bolts

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Ensures a secure and grounded connection for the ECM/PCM. Tighten evenly to prevent damage. Poor ground connections may lead to intermittent operation.

Ground Connections

Torque specifications for ground strap connections to the chassis/body, ensuring proper and low-resistance electrical pathways.

1

Ground Strap/Wire Mounting Bolts

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Ensures proper grounding of the electrical system. A range of bolts may be used, ensure bolt is of proper size before torquing. Clean mating surfaces before installation. This is an estimated value. If using a M8 bolt, torque to 14 ft-lbs (19 N·m).

Sensor Mounts

Torque specifications for various engine sensors, ensuring secure mounting and proper grounding (where applicable).

1

Crankshaft Position Sensor Mounting Bolt

M6 x 1.0
Torque Value
6.6 ft-lbs (9 N·m)
Important Notes
Proper torque is important for secure mounting and signal integrity. This is an estimated value.
2

Camshaft Position Sensor Mounting Bolt

M6 x 1.0
Torque Value
6.6 ft-lbs (9 N·m)
Important Notes
Proper torque ensures secure sensor mounting and signal integrity. This is an estimated value.
3

MAP Sensor Mounting Bolt

M5 x 0.8
Torque Value
6.2 ft-lbs (8.4 N·m)
Important Notes
Proper torque is important for secure mounting, signal integrity and prevent vacuum leaks. This is an estimated value.

Lighting System

Torque specifications for headlight and taillight housings, ensuring proper fit and preventing damage.

1

Headlight Mounting Screws/Bolts

M5 x 0.8
Torque Value
3.7 ft-lbs (5 N·m)
Important Notes
Prevents vibration and housing damage. Use caution when tightening to prevent over-tightening. This is an estimated value.
2

Taillight Mounting Screws/Bolts

M5 x 0.8
Torque Value
3.7 ft-lbs (5 N·m)
Important Notes
Prevents vibration and housing damage. Use caution when tightening to prevent over-tightening. This is an estimated value.

Power Distribution

Torque specifications for mounting the fuse box/power distribution center, ensuring a secure and grounded connection.

1

Fuse Box/Power Distribution Center Mounting Bolts

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Ensures proper electrical distribution. Loose mounts could lead to intermittent connections. Torque evenly to prevent damage.

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 is it important to use the correct torque specifications for electrical connections?

Using the correct torque ensures a secure and reliable electrical connection. Under-tightening can lead to high resistance, overheating, and potential failure due to arcing. Over-tightening can damage the connector, wiring, or the component itself, leading to premature failure and potential electrical malfunctions. It's also crucial for consistent electrical conductivity.

Q2

What happens if I overtighten an electrical bolt?

Overtightening can crush the terminal, distort the connector housing, and even strip the threads in the component or wiring harness. This can lead to a broken connection, causing intermittent faults or complete failure of the electrical circuit. In some cases, it can also lead to damage to the wiring itself, requiring more extensive repairs.

Q3

Can I reuse electrical bolts and fasteners?

Generally, it's not recommended to reuse electrical bolts, especially those that are self-locking or torque-to-yield. While some may appear reusable, repeated use can compromise their integrity and clamping force, leading to unreliable connections over time. It's always best to use new fasteners whenever possible, particularly in critical electrical circuits to ensure optimal performance and reliability.

Q4

Where can I find the specific torque values for my 2017-2019 Buick LaCrosse's electrical components?

The most reliable source for torque specifications is the official service manual for your specific vehicle year and trim. These manuals are often available through dealerships, online automotive service information providers, or specialized repair database subscriptions. Always refer to the manual rather than relying on generic online forums or guides for your specific vehicle.

Q5

What should I do if I accidentally overtightened an electrical bolt?

If you suspect an electrical bolt has been overtightened, it's best to inspect the connection and surrounding components immediately. Check for signs of damage like cracking, warping, or stripped threads. It's advisable to replace the bolt and any damaged hardware to maintain a safe and reliable connection. If there's any uncertainty, consulting a qualified mechanic is the best approach.

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 (1/4-inch Drive)

A calibrated torque wrench is essential for accurately tightening electrical connections to specified torque values. A 1/4-inch drive is suitable for many smaller fasteners in the electrical system.

  • Adjustable torque settings
  • Click-type or digital readout
  • Accurate within +/- 3%
Learn more

Torque Wrench (3/8-inch Drive)

A 3/8-inch drive torque wrench is suitable for slightly larger fasteners or those requiring a higher torque rating in the electrical system.

  • Adjustable torque settings
  • Click-type or digital readout
  • Accurate within +/- 3%
Learn more

Socket Set (Standard and Metric)

A comprehensive set of sockets, including both standard and metric sizes, is necessary to accommodate the various fasteners used in the electrical system.

  • Wide range of sizes
  • 6-point and 12-point options
  • Durable construction
Learn more

Extension Bars

Extension bars provide reach for fasteners in recessed or difficult-to-access areas.

  • Various lengths available
  • Durable construction
  • Secure attachment
Learn more

Multi-meter

A multi-meter is critical for testing electrical circuits.

  • Voltage, Amperage, and Ohm measurements
  • Continuity testing
  • Digital readout
Learn more
Service Procedures

Battery Terminal Tightening Procedure

Properly tightening battery terminals is crucial for a reliable electrical connection. Loose connections can cause intermittent starting or charging issues.

  • Disconnect the negative battery terminal.
  • Clean the battery posts and terminals with a wire brush.
  • Reconnect the terminals to the posts.
  • Torque the terminal fasteners to the manufacturer's specification (typically 8-10 lb-ft).
  • Reconnect the negative battery terminal.
View full procedure

Ground Connection Inspection and Tightening

Inspect and ensure all ground connections are clean, secure, and properly tightened.

  • Locate and identify all ground connection points in the engine bay and passenger compartment.
  • Visually inspect connections for corrosion or damage.
  • Disconnect one at a time, clean the terminals and mating surfaces with a wire brush or abrasive pad.
  • Reconnect and torque each ground connection to the manufacturer's specification (typically 8-10 lb-ft for smaller bolts, 15-20 lb-ft for larger bolts).
  • Verify secure connection and functionality.
View full procedure

Alternator Wiring Harness Connections

Tighten all connections at the alternator including the main power wire and signal wires to the manufacturer's torque specification. Ensure no corrosion is present.

  • Disconnect the negative battery terminal.
  • Locate the alternator connections (main power, signal and chassis ground)
  • Inspect the connections for corrosion or damage.
  • Disconnect the connections, one at a time, and clean if necessary.
  • Reconnect the alternator wires to the alternator connections and torque to manufacturer specification (typically 8-10 lb-ft for small bolts, 12-15 lb-ft for the main terminal nut).
  • Reconnect the negative battery terminal.
View full procedure
Technical Service Bulletins

Corrosion Issues on Battery Terminals and Ground Points

2018-07-15

Some vehicles may experience corrosion on battery terminals and ground points, which can lead to electrical issues. This bulletin addresses inspecting and correctly tightening these.

2017-2019 Buick LaCrosse

Resolution: Clean the terminals and apply dielectric grease. Tighten to specification (8-10 lb-ft). Check for proper grounding.

Loose Alternator Connections

2019-02-28

Reports of loose alternator connections causing intermittent charging problems. Bulletin outlines a procedure to inspect and tighten the main power, signal, and ground connections.

2017-2019 Buick LaCrosse

Resolution: Disconnect negative terminal, inspect and clean connections if necessary. Reconnect wires and tighten to specification (typically 8-10 lb-ft for small bolts, 12-15 lb-ft for main terminal nut).

Ground Bolt Breakage/Stripping

2018-11-10

Some ground locations are exhibiting broken or stripped bolt threads if over tightened. Use caution, and torque to specification.

2017-2019 Buick LaCrosse

Resolution: Ensure that ground connections are properly torqued. Replace stripped bolts or ground connection points and re-torque.

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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