Subaru Subaru Impreza 1992-2000 Exhaust System Bolt Torque Specifications & Gasket Sealing
Subaru Subaru Impreza 1992-2000

Subaru Subaru Impreza 1992-2000 Exhaust System Bolt Torque Specifications

Detailed torque specifications for the exhaust bolts on the 1992-2000 Subaru Impreza, including manifold, downpipe, and exhaust flange bolts.

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 Headers

This subsystem includes components that connect the exhaust manifold or headers to the cylinder head and exhaust pipe. Proper torque ensures a tight seal to prevent exhaust leaks, which can affect engine performance and emissions.

1

Exhaust Manifold/Headers to Cylinder Head Bolts

M10 x 1.25
Torque Value
25.5 ft-lbs (35 N·m)
Important Notes
Torque value is an average of the provided range (22-29 ft-lbs).
2

Exhaust Pipe to Exhaust Manifold/Headers Bolts

M10 x 1.25
Torque Value
25.5 ft-lbs (35 N·m)
Important Notes
Torque value is an average of the provided range (22-29 ft-lbs).

Catalytic Converter

This subsystem includes components that connect the catalytic converter to the exhaust pipe. Proper torque ensures a tight seal to prevent exhaust leaks and maintain proper exhaust flow, which is critical for emissions control.

1

Catalytic Converter to Exhaust Pipe Bolts

M10 x 1.25
Torque Value
25.5 ft-lbs (35 N·m)
Important Notes
Torque value is an average of the provided range (22-29 ft-lbs).

Muffler

This subsystem includes components that connect the muffler to the exhaust pipe. Proper torque ensures a secure connection, preventing leaks and reducing noise from the exhaust system.

1

Muffler to Exhaust Pipe Bolts

M10 x 1.25
Torque Value
25.5 ft-lbs (35 N·m)
Important Notes
Torque value is an average of the provided range (22-29 ft-lbs).

Egr Valve

This subsystem includes the EGR (Exhaust Gas Recirculation) valve, which is part of the emissions system and is connected to the exhaust manifold. Proper torque ensures a secure fit and prevents exhaust gas leaks, which could affect emissions and engine performance.

1

EGR Valve Bolts

M8 x 1.25
Torque Value
18.5 ft-lbs (25 N·m)
Important Notes
Torque value is an average of the provided range (17-20 ft-lbs).

Heat Shield

This subsystem includes heat shields that are attached to the exhaust system to protect surrounding components from excessive heat. Proper torque ensures they remain securely in place without over-tightening, which could damage the shield or exhaust components.

1

Exhaust Heat Shield Bolts

M6 x 1.0
Torque Value
8 ft-lbs (11 N·m)
Important Notes
Torque value is an average of the provided range (7-9 ft-lbs).

Oxygen Sensor

This subsystem includes oxygen sensors (O2 sensors) that monitor exhaust gases for emissions control. Proper torque ensures a secure fit and prevents leaks, which could lead to inaccurate sensor readings and poor engine performance.

1

Oxygen Sensor (O2 Sensor)

M12 x 1.25
Torque Value
35 ft-lbs (47 N·m)
Important Notes
Torque value is an average of the provided range (30-40 ft-lbs).

Exhaust Flange

This subsystem includes flange bolts that connect different sections of the exhaust system, such as the downpipe to the midpipe. Proper torque ensures a tight seal and prevents leaks, which could cause noise and emissions issues.

1

Exhaust Flange Bolts (Downpipe to Midpipe)

M10 x 1.25
Torque Value
25.5 ft-lbs (35 N·m)
Important Notes
Torque value is an average of the provided range (22-29 ft-lbs).

Exhaust Hanger

This subsystem includes exhaust hangers that secure the exhaust system to the vehicle's underbody. Proper torque ensures the exhaust system remains stable and prevents excessive movement, which could lead to stress on other components or rattling noises.

1

Exhaust Hanger Bolts

M8 x 1.25
Torque Value
16 ft-lbs (22 N·m)
Important Notes
Torque value is an average of the provided range (14-18 ft-lbs).

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 recommended torque for exhaust bolts on a 1992-2000 Subaru Impreza?

The recommended torque for exhaust bolts on a 1992-2000 Subaru Impreza is typically 25-30 Nm (Newton meters). However, this can vary depending on the specific exhaust component (e.g., manifold, flange, or mounting bolts). Always refer to the manufacturer's service manual for precise specifications.

Q2

Can over-tightening exhaust bolts cause damage?

Yes, over-tightening exhaust bolts can lead to stripped threads, cracked exhaust components, or warped flanges. Over-torqueing may also cause leaks due to improper sealing. Always follow the recommended torque specifications and use a calibrated torque wrench.

Q3

How often should exhaust bolts be checked for tightness?

Exhaust bolts should be checked periodically, especially after major temperature fluctuations (e.g., winter to summer) or after long drives. A common real-world scenario is checking bolts after noticing exhaust rattling or unusual noises, which often indicates loosened bolts.

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 exhaust bolts.

  • Adjustable torque settings
  • Calibrated for accuracy
Learn more

Socket Set

A set of sockets compatible with exhaust bolt sizes, typically including 12mm, 14mm, and 17mm sockets.

  • Durable chrome vanadium construction
  • Includes extensions and adapters
Learn more

Breaker Bar

A long-handled tool used to loosen tight bolts before applying torque.

  • High leverage for tough bolts
  • Durable steel construction
Learn more
Service Procedures

Exhaust Manifold Bolt Torque Procedure

Step-by-step guide to properly torque the exhaust manifold bolts on a 1992-2000 Subaru Impreza.

  • Ensure the engine is cool before starting.
  • Remove the heat shield to access the exhaust manifold bolts.
  • Use a breaker bar to loosen the bolts if necessary.
  • Clean the bolt threads and apply anti-seize compound.
  • Tighten the bolts in a crisscross pattern to the specified torque of 22-25 ft-lbs.
  • Reinstall the heat shield and check for leaks.
View full procedure

Exhaust Pipe Flange Bolt Torque Procedure

Procedure for torquing the exhaust pipe flange bolts to prevent leaks and ensure proper sealing.

  • Raise the vehicle and secure it on jack stands.
  • Locate the exhaust pipe flange connection.
  • Use a torque wrench to tighten the flange bolts to 25-30 ft-lbs.
  • Check for proper alignment and ensure no exhaust leaks are present.
  • Lower the vehicle and test drive to confirm proper installation.
View full procedure
Technical Service Bulletins

Exhaust Manifold Bolt Loosening Issue

1998-05-15

Reports of exhaust manifold bolts loosening over time, leading to exhaust leaks.

1992-2000 Subaru Impreza

Resolution: Apply thread locker to the exhaust manifold bolts during installation and ensure proper torque is applied.

Exhaust Flange Gasket Failure

1999-08-20

Frequent failure of exhaust flange gaskets due to improper torque application.

1992-2000 Subaru Impreza

Resolution: Replace the gasket and torque the flange bolts to the specified 25-30 ft-lbs using a calibrated torque wrench.

About the Author

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Alan Montanye - Automotive Technical Specialist
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Alan Montanye

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