Audi Audi A5 2016-present Exhaust System Bolt Torque Specifications
Detailed torque specifications for all exhaust system bolts on the 2016-Present Audi A5 (B9) generation. Includes flange bolts, clamp bolts, and hanger bolts.
Important Information
Safety guidelines and reference information for proper torque application
Safety First
- Always verify torque specifications with your vehicle's factory service manual
- Use properly calibrated torque wrenches
- Replace all torque-to-yield (TTY) bolts - they are single-use only
- When in doubt, consult a professional mechanic
Quick Reference Guide
Quick Reference Guide
Common Torque Patterns
Star Pattern
Used for wheels and other circular bolt patterns
Cross Pattern
Used for gaskets and cover plates
Sequential Pattern
Used for head bolts and other critical components
Common Mistakes to Avoid
Common Mistakes to Avoid
Over-tightening
Exceeding the specified torque value can stretch or break fasteners, damage threads, or crack components.
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.
Follow the manufacturer's specified torque sequence pattern.
Dirty Threads
Dirt, rust, or old thread locker can affect torque readings and proper fastener tension.
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.
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.
Check if specs are for dry or lubricated threads. Use specified lubricant when required.
Recommended Tools
Recommended Tools
Torque Wrench (1/4" Drive)
Torque Wrench (3/8" Drive)
Torque Wrench (1/2" Drive)
Angle Gauge
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
The exhaust manifold/headers collect exhaust gases from the engine cylinders and direct them into the exhaust system.
1 Exhaust Manifold/Headers Bolts
M12 x 1.5
Exhaust Manifold/Headers Bolts
M12 x 1.5Torque Value
Important Notes
2 Exhaust Manifold/Headers to Cylinder Head Bolts
M12 x 1.5
Exhaust Manifold/Headers to Cylinder Head Bolts
M12 x 1.5Torque Value
Important Notes
Exhaust Pipe
The exhaust pipe carries exhaust gases from the exhaust manifold/headers to the catalytic converter.
1 Exhaust Pipe to Exhaust Manifold/Headers Bolts
M12 x 1.5
Exhaust Pipe to Exhaust Manifold/Headers Bolts
M12 x 1.5Torque Value
Important Notes
Catalytic Converter
The catalytic converter reduces emissions by converting exhaust gases into harmless substances.
1 Catalytic Converter to Exhaust Pipe Bolts
M12 x 1.5
Catalytic Converter to Exhaust Pipe Bolts
M12 x 1.5Torque Value
Important Notes
Muffler
The muffler reduces exhaust noise by dissipating the energy of the exhaust gases.
1 Muffler to Exhaust Pipe Bolts
M12 x 1.5
Muffler to Exhaust Pipe Bolts
M12 x 1.5Torque Value
Important Notes
Oxygen Sensor
The oxygen sensor monitors the oxygen levels in the exhaust gases and provides feedback to the engine control unit.
1 Oxygen Sensor Bolts
M10 x 1.25
Oxygen Sensor Bolts
M10 x 1.25Torque Value
Important Notes
Exhaust System Mounting
The exhaust system mounting components secure the exhaust system to the vehicle's chassis or engine.
1 Exhaust System Mounting Bolts
M14 x 1.5
Exhaust System Mounting Bolts
M14 x 1.5Torque Value
Important Notes
Turbocharger
The turbocharger compresses the air entering the engine, increasing power and efficiency.
1 Turbocharger Bolts
M16 x 1.5
Turbocharger Bolts
M16 x 1.5Torque Value
Important Notes
Exhaust System Heat Shield
The exhaust system heat shield protects the surrounding components from heat damage.
1 Exhaust System Heat Shield Bolts
M10 x 1.25
Exhaust System Heat Shield Bolts
M10 x 1.25Torque Value
Important Notes
Troubleshooting Guide
Common issues, diagnostic steps, and prevention guidelines
Common Issues
Bolt stretching, stripped threads, uneven torque patterns
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
Diagnostic Steps
Visual inspection, torque verification, thread assessment
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
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
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
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 using the correct torque specification important for exhaust bolts?
Why is using the correct torque specification important for exhaust bolts?
Using the correct torque specification is crucial for preventing leaks, component failure, and ensuring proper sealing. Over-tightening can stretch or break bolts, causing exhaust leaks or damage to mounting surfaces. Under-tightening can lead to loosening of bolts over time, also resulting in leaks and potential damage from vibration. For example, if the bolts connecting the downpipe to the exhaust manifold are not torqued properly, they can loosen from the engine vibration, causing a significant leak which can have a very harmful effect on the cars efficiency and performance.
Q2 Do torque specifications change when using aftermarket exhaust components?
Do torque specifications change when using aftermarket exhaust components?
Yes, torque specifications might differ when using aftermarket exhaust components. Always consult the manufacturer's instructions provided with the aftermarket parts. They often specify different torque values due to material differences or design variations. Failing to do so could result in component damage or improper installation. A good example is if a aftermarket downpipe is installed, you may need to use torque specs specific to the new components.
Q3 Should I use new bolts when reassembling the exhaust system?
Should I use new bolts when reassembling the exhaust system?
It is highly recommended to use new bolts when reassembling the exhaust system. Exhaust bolts can stretch or become fatigued over time, especially from the high temperatures and vibrations. Reusing old bolts can compromise the seal and lead to future problems. It's a small investment that can prevent significant headaches down the line. For example, if you are replacing the gasket between the exhaust manifold and the downpipe you should always use new hardware, old hardware could have stretched or become damaged from repeated exposure to heat.
Q4 What type of lubricant should I use on exhaust bolts?
What type of lubricant should I use on exhaust bolts?
Generally, it's recommended to use an anti-seize lubricant on exhaust bolts, particularly those that are exposed to high temperatures. Anti-seize helps prevent the bolts from seizing (welding) to the exhaust components and makes future removal much easier. Do not use standard oil. Apply the anti-seize lubricant sparingly to the threads of the bolts, avoiding contact with the mounting surfaces to ensure a good, even torque.
Q5 Can I reuse exhaust gaskets?
Can I reuse exhaust gaskets?
It's best practice to replace exhaust gaskets whenever they are removed. Gaskets are designed to crush and seal when tightened and are typically not reusable. Reusing old gaskets can lead to exhaust leaks, which will decrease performance and can cause harmful gases to vent where they shouldn't. Always use fresh gaskets when reinstalling the exhaust system, even if they appear to be in good condition. A common issue with reusing a gasket is it may not provide a proper seal between the downpipe and exhaust manifold, which will cause a leak.
Environmental Considerations
Temperature, humidity, and seasonal effects on torque specifications
Temperature Effects
Includes: High Heat, Cold Weather, Thermal Cycling
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
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
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" Drive)
A calibrated torque wrench is essential for accurately tightening exhaust bolts to the manufacturer's specifications. A 1/2" drive is suitable for most exhaust bolts.
- Accurate torque measurement
- Click-type mechanism for feedback
- Suitable for a wide range of torque values
Torque Wrench (3/8" Drive)
A smaller 3/8" drive torque wrench can be helpful for tighter areas or smaller bolts sometimes used on exhaust systems.
- Suitable for lower torque values
- More compact for tighter spaces
- Accurate torque application
Socket Set (Metric)
A comprehensive set of metric sockets is necessary to fit the various bolt and nut head sizes used on the exhaust system. Common sizes include 13mm, 16mm, and 17mm.
- Sizes suitable for exhaust hardware
- Multiple drive sizes
- Durable construction
Extension Bars
Extension bars are necessary to reach difficult exhaust bolts. Various lengths may be needed.
- Extends reach
- Multiple lengths for various applications
- Durable construction
Universal Joint
A universal joint or swivel adapter can provide the necessary flexibility to access awkwardly positioned bolts.
- Adds flexibility to a socket
- Enables access to difficult angles
- Durable construction
Penetrating Oil
Penetrating oil helps to loosen corroded or stuck bolts, making removal easier and reducing the risk of damage.
- Lubricates corroded fasteners
- Reduces removal force
- Helps prevent bolt breakage
Service Procedures
Exhaust Manifold to Cylinder Head Bolt Torque Procedure
Procedure for torquing bolts connecting the exhaust manifold to the cylinder head. These bolts are critical for proper sealing and should be tightened in a specific sequence.
- Locate the exhaust manifold bolts.
- Apply penetrating oil if necessary to aid in removal.
- Loosen all bolts before removing completely.
- Clean all mating surfaces.
- Install the manifold and evenly tighten all bolts by hand initially.
- Using the torque wrench, torque the bolts to 25 Nm in a criss-cross pattern.
- Re-torque to 25 Nm and then an additional 90 degrees.
- Inspect for proper sealing and any leaks.
Exhaust Downpipe to Turbocharger/Manifold Bolt Torque Procedure
Procedure for torquing the bolts connecting the downpipe to the turbocharger or exhaust manifold. These bolts are critical due to the high temperatures and vibrations.
- Locate the downpipe to turbocharger/manifold bolts.
- Apply penetrating oil if necessary to aid in removal.
- Loosen all bolts before removing completely.
- Clean all mating surfaces.
- Install the downpipe and evenly tighten all bolts by hand initially.
- Using the torque wrench, torque the bolts to 40 Nm.
- Inspect for proper sealing and any leaks.
Exhaust Mid-pipe Flange Bolt Torque Procedure
Procedure for torquing bolts on the flange connections between the mid-pipe sections of the exhaust system.
- Locate the mid-pipe flange bolts.
- Apply penetrating oil if necessary to aid in removal.
- Loosen all bolts before removing completely.
- Clean all mating surfaces.
- Install the mid-pipe and evenly tighten all bolts by hand initially.
- Using the torque wrench, torque the bolts to 20 Nm.
- Inspect for proper sealing and any leaks.
Exhaust Hanger Bolt Torque Procedure
Procedure for torquing bolts that secure the exhaust hangers to the vehicle chassis. These bolts should be torqued to ensure the exhaust is securely supported.
- Locate the exhaust hanger bolts.
- Hand tighten all bolts.
- Using the torque wrench, torque the bolts to 25 Nm.
- Check to see the hangers are securely attached
Technical Service Bulletins
Exhaust Bolt Corrosion and Replacement Recommendations
2018-05-15Technical bulletin addressing concerns about exhaust bolt corrosion and recommendations for replacement using appropriate materials for longevity.
Resolution: Replace exhaust bolts with high-strength, corrosion-resistant fasteners. Apply anti-seize compound during installation. Inspect bolts yearly for corrosion.
Exhaust Leakage Due to Improper Bolt Torque
2020-11-20Technical bulletin regarding exhaust leaks caused by improper torque during reassembly. Emphasis on importance of using proper torque specifications and torque wrenches.
Resolution: Retorque exhaust bolts according to factory specifications. Ensure a calibrated torque wrench is used. Use new gaskets or seals if required.
Updated Torque Specifications for Exhaust Manifold Bolts
2022-03-01Updated torque specifications for exhaust manifold bolts due to issues with bolt stretching after multiple thermal cycles.
Resolution: Torque exhaust manifold bolts to 20 Nm and then an additional 90 degrees. This replaces earlier specifications of 25 Nm + 90 degrees for these models.
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Technical Information
- All specifications, including torque values, fluid capacities, and maintenance procedures, should be verified against your vehicle's factory service manual.
- Vehicle specifications and procedures may vary by model year, trim level, and region.
- Always follow the manufacturer's recommended procedures and safety precautions.
- Working on vehicles can be dangerous. Always take proper safety precautions and use appropriate safety equipment.
- If you're unsure about any procedure, consult a qualified professional mechanic.