Subaru Subaru WRX 2014-2021 Exhaust System Bolt Torque Specifications & Gasket Sealing
Subaru Subaru WRX 2014-2021

Subaru Subaru WRX 2014-2021 Exhaust System Bolt Torque Specifications

Detailed torque specifications and guidelines for exhaust bolts on the 2014-2021 Subaru WRX. Includes OEM recommended values and installation tips.

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

Exhaust Manifold

The exhaust manifold or headers are critical components that collect exhaust gases from the engine cylinders and direct them into the exhaust system. Proper torque ensures a tight seal and prevents leaks.

1

Exhaust Manifold/Headers Bolts

M8 x 1.25
Torque Value
25.5 ft-lbs (34.5 N·m)
Important Notes
Torque values are the midpoint of the provided range. Ensure bolts are tightened in a crisscross pattern.
2

Exhaust Manifold/Headers to Cylinder Head Bolts

M8 x 1.25
Torque Value
20.5 ft-lbs (27.5 N·m)
Important Notes
Torque values are the midpoint of the provided range. Use a crisscross pattern for tightening.

Exhaust Pipes

The exhaust pipe connects the exhaust manifold to the catalytic converter and other downstream components. Proper torque ensures leak-free connections and optimal exhaust flow.

1

Exhaust Pipe to Exhaust Manifold/Headers Bolts

M8 x 1.25
Torque Value
25.5 ft-lbs (34.5 N·m)
Important Notes
Torque values are the midpoint of the provided range.
2

Catalytic Converter to Exhaust Pipe Bolts

M8 x 1.25
Torque Value
25.5 ft-lbs (34.5 N·m)
Important Notes
Torque values are the midpoint of the provided range.
3

Exhaust Downpipe to Turbocharger Bolts

M8 x 1.25
Torque Value
25.5 ft-lbs (34.5 N·m)
Important Notes
Estimated value based on similar exhaust connections. Ensure a leak-free seal.

Muffler

The muffler reduces exhaust noise and directs exhaust gases out of the vehicle. Proper torque ensures a secure connection and minimizes vibrations.

1

Muffler to Exhaust Pipe Bolts

M8 x 1.25
Torque Value
25.5 ft-lbs (34.5 N·m)
Important Notes
Torque values are the midpoint of the provided range.

Oxygen Sensor

The oxygen sensor monitors the oxygen content in the exhaust gases, providing critical data to the engine control unit (ECU) for optimal fuel management.

1

Oxygen Sensor (O2 Sensor)

M12 x 1.5
Torque Value
25.5 ft-lbs (34.5 N·m)
Important Notes
Estimated value based on similar sensors. Ensure proper sealing to prevent exhaust leaks.

Exhaust Hangers

Exhaust hangers secure the exhaust system to the vehicle’s chassis, reducing vibrations and preventing damage to exhaust components.

1

Exhaust Hanger Bolts

M6 x 1.0
Torque Value
16 ft-lbs (22 N·m)
Important Notes
Estimated value based on similar chassis-mounted components.

Heat Shields

Heat shields protect surrounding components from the high temperatures of the exhaust system. Proper torque prevents rattling and ensures secure mounting.

1

Exhaust Heat Shield Bolts

M6 x 1.0
Torque Value
10 ft-lbs (13.5 N·m)
Important Notes
Estimated value based on similar small fasteners.

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

What is the torque specification for the exhaust manifold bolts on a 2014-2021 Subaru WRX?

The torque specification for the exhaust manifold bolts is 33.3 ft-lbs (45 Nm). Ensure the engine is cool before tightening to prevent warping or damage to the manifold.

Q2

What happens if I over-torque the exhaust bolts?

Over-torquing can cause the bolts to stretch or break, damage the exhaust manifold, or create leaks. Always use a calibrated torque wrench to ensure accuracy.

Q3

Do I need to re-torque the exhaust bolts after driving?

It is recommended to check the torque after the first 50-100 miles of driving, as heat cycles can cause bolts to loosen slightly. Re-torque while the engine is cool.

Q4

Can I reuse the exhaust manifold gasket?

No, Subaru recommends replacing the exhaust manifold gasket every time the manifold is removed to ensure a proper seal and prevent exhaust leaks.

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

A precision tool used to apply a specific torque to a fastener, such as an exhaust bolt.

  • Adjustable torque settings
  • Durable construction
Learn more

Socket Set

A set of sockets in various sizes to fit exhaust bolt heads.

  • Multiple sizes included
  • Compatible with torque wrench
Learn more

Penetrating Oil

A chemical solution used to loosen rusted or stuck bolts.

  • Helps prevent bolt breakage
  • Improves ease of removal
Learn more
Service Procedures

Exhaust Bolt Torque Specification Application

Procedure to properly apply torque to exhaust bolts on a 2014-2021 Subaru WRX.

  • Ensure the vehicle is on a lift or jack stands for safe access to the exhaust system.
  • Clean the exhaust bolt threads using a wire brush and apply penetrating oil if necessary.
  • Install the exhaust bolts and hand-tighten them.
  • Use a torque wrench set to the specified torque value (e.g., 28 ft-lbs for exhaust manifold bolts).
  • Double-check the torque application to ensure proper tightening.
View full procedure
Technical Service Bulletins

Exhaust Bolt Torque Specification Update

2016-05-12

Updated torque specifications for exhaust system bolts on 2014-2016 Subaru WRX models.

2014-2016 Subaru WRX

Resolution: Follow the revised torque specifications in the service manual to ensure proper installation.

Exhaust Bolt Corrosion Issue

2019-08-20

Reports of exhaust bolt corrosion leading to breakage during removal on 2017-2019 Subaru WRX models.

2017-2019 Subaru WRX

Resolution: Replace corroded bolts with new, coated bolts and apply anti-seize compound during installation.

About the Author

Expert automotive knowledge and experience

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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