Audi Audi S5 2007-2016 Emissions & Sensor Bolt Torque Specifications
Audi Audi S5 2007-2016

Audi Audi S5 2007-2016 Emissions & Sensor Bolt Torque Specifications

Detailed torque specifications for all emissions related sensors on the 2007-2016 Audi S5, including oxygen sensors, NOx sensors, and temperature sensors. Includes torque values for both new and used 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

Oxygen Sensors

Specifications for mounting pre-catalyst and post-catalyst oxygen sensors to the exhaust system. Proper torque is crucial for preventing exhaust leaks and ensuring accurate sensor readings.

1

Pre-Catalyst Oxygen Sensor Mounting Bolts/Studs

M18 x 1.5
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Ensure threads are clean and apply anti-seize compound to aid future disassembly. Do not get any on the sensor itself.
2

Post-Catalyst Oxygen Sensor Mounting Bolts/Studs

M18 x 1.5
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Ensure threads are clean and apply anti-seize compound to aid future disassembly. Do not get any on the sensor itself.

Air Intake

Specifications for mounting sensors related to the air intake system, including the mass air flow (MAF) and manifold absolute pressure (MAP) sensors.

1

Mass Air Flow (MAF) Sensor Mounting Screws

M5 x 0.8
Torque Value
4.5 ft-lbs (6 N·m)
Important Notes
These screws often secure the MAF sensor to a plastic housing. Over-tightening can crack the housing. Estimated value.
2

Intake Manifold Pressure (MAP) Sensor Mounting Screws

M5 x 0.8
Torque Value
7 ft-lbs (9.5 N·m)
Important Notes
Ensure sensor is seated correctly before tightening. Estimated value.

Exhaust System

Specifications for mounting exhaust components, including exhaust gas temperature (EGT) sensors and catalytic converter mounting hardware. Proper torque is crucial for preventing exhaust leaks and maintaining system integrity.

1

Exhaust Gas Temperature (EGT) Sensor Mounting Bolts/Studs

M10 x 1.5
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Apply anti-seize compound. Ensure sensor is properly seated before tightening. Estimated value.
2

Catalytic Converter Flange Bolts (to exhaust)

M10 x 1.5
Torque Value
33 ft-lbs (45 N·m)
Important Notes
Tighten flange bolts in a criss-cross pattern to ensure even pressure. Estimated value.
3

Catalytic Converter Mounting Bolts (to chassis)

M10 x 1.5
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Ensure proper alignment of the catalytic converter. Estimated value.

Evaporative Emissions

Specifications for mounting components of the evaporative emissions system, including the EVAP purge valve and canister. Proper torque ensures system integrity and prevents leaks.

1

Evaporative Emissions (EVAP) Purge Valve Mounting Screws

M5 x 0.8
Torque Value
6 ft-lbs (8 N·m)
Important Notes
These screws often secure the purge valve to a plastic housing. Over-tightening can crack the housing. Estimated value.
2

EVAP Canister Mounting Bolts

M8 x 1.25
Torque Value
15 ft-lbs (20 N·m)
Important Notes
Ensure the canister is properly aligned before tightening.
3

Leak Detection Pump (LDP) Mounting Screws/Bolts

M6 x 1.0
Torque Value
8 ft-lbs (11 N·m)
Important Notes
Ensure proper seating before tightening. Estimated value.

Nox Sensors

Specifications for mounting NOx sensors to the exhaust system. Proper torque is crucial for preventing exhaust leaks and ensuring accurate sensor readings.

1

NOx Sensor Mounting Bolts/Studs

M18 x 1.5
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Ensure threads are clean and apply anti-seize compound to aid future disassembly. Do not get any on the sensor itself. Estimated value.

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 specification for emissions sensor bolts?

Using the correct torque is crucial to ensure a proper seal and prevent damage to the sensor and threads. Over-tightening can lead to stripped threads or cracked sensor housings, while under-tightening can cause leaks and inaccurate readings. For example, an improperly torqued oxygen sensor can lead to exhaust leaks and misreadings that cause the check engine light to illuminate.

Q2

What happens if I over-tighten an emissions sensor bolt?

Over-tightening can damage the sensor, the threads in the exhaust system, or even the mounting bracket. This could mean a damaged sensor, causing inaccurate readings. In a real-world scenario, an over-tightened Mass Air Flow (MAF) sensor bolt could cause the sensor housing to crack, needing a complete replacement.

Q3

Are torque specs the same for all emissions sensors on a 2007-2016 Audi S5?

No, torque specifications can vary depending on the specific sensor and its location. Always refer to the manufacturer's service manual or a reliable database to confirm the correct torque spec for each individual sensor such as the oxygen sensors, MAF sensor and NOx sensor. For instance, the torque for an O2 sensor on the downpipe is generally different than that of a NOx sensor closer to the rear.

Q4

Can I reuse emissions sensor mounting hardware after removal?

It is generally recommended to replace gaskets and any self-locking nuts or bolts. While a bolt might 'look' fine, it can be stretched or weakened, causing improper torque to be achieved on reinstallation and subsequent leakage or loosening. Consider replacing them for a proper seal to prevent errors in your sensors system.

Q5

What should I do if I don't have a torque wrench?

A torque wrench is highly recommended for achieving the proper torque. While some experienced individuals might feel comfortable without one, it's highly risky. Avoid guessing the torque, as this can easily lead to sensor or thread damage. If you absolutely cannot access one, it's highly recommended to wait until you do.

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" or 3/8" Drive)

A calibrated torque wrench is essential for accurately tightening bolts to the specified torque, preventing damage and ensuring proper sensor function. Smaller drive sizes are recommended due to the tight spaces around emissions sensors.

  • Accurate torque measurement
  • Click-type or digital readout
  • Range suitable for 5-20 Nm torques
Learn more

Socket Set (Metric)

A standard metric socket set will be needed for removing and installing the emissions sensor bolts. Common sizes will include 10mm and 13mm. A 1/4" drive socket set is recommended for access.

  • Metric sizes
  • Various socket depths
  • 1/4" and/or 3/8" Drive
Learn more

Extension Bars

Extension bars of varying lengths are often necessary to reach recessed or difficult-to-access emissions sensors. A 3" and 6" bar is recommended.

  • Various lengths
  • 1/4" and/or 3/8" Drive compatibility
Learn more

Universal Joint

A universal joint can be helpful when needing to access emissions sensor bolts at awkward angles.

  • 1/4" and/or 3/8" Drive compatibility
  • Allows for angled sockets
Learn more
Service Procedures

Oxygen Sensor Replacement

Procedure for removing and reinstalling an oxygen sensor while ensuring proper torque is applied.

  • Disconnect the negative battery terminal.
  • Locate the oxygen sensor(s) requiring replacement (pre-cat, post-cat, etc.).
  • Disconnect the sensor's electrical connector.
  • Using the correct socket size, remove the old oxygen sensor from the exhaust system.
  • Install the new oxygen sensor, threading it in by hand to avoid cross-threading.
  • Tighten the oxygen sensor to the specified torque (typically 40-50 Nm) using the calibrated torque wrench.
  • Reconnect the sensor's electrical connector.
  • Reconnect the negative battery terminal.
  • Verify correct sensor operation with a scan tool (if applicable).
View full procedure

NOx Sensor Replacement

Procedure for removing and reinstalling a NOx sensor while ensuring proper torque is applied.

  • Disconnect the negative battery terminal.
  • Locate the NOx sensor(s) on the exhaust system.
  • Disconnect the sensor's electrical connector.
  • Remove any heat shielding or other components blocking access to the sensor.
  • Using the correct socket size, remove the NOx sensor from the exhaust system or mounting bracket.
  • Install the new NOx sensor, threading it in by hand to avoid cross-threading.
  • Tighten the NOx sensor to the specified torque (typically 15-20 Nm) using the calibrated torque wrench.
  • Reinstall any removed heat shields and components.
  • Reconnect the sensor's electrical connector.
  • Reconnect the negative battery terminal.
  • Verify correct sensor operation with a scan tool.
View full procedure

Exhaust Gas Temperature (EGT) Sensor Replacement

Procedure for removing and reinstalling an EGT sensor while ensuring proper torque is applied.

  • Disconnect the negative battery terminal.
  • Locate the EGT sensor(s) on the exhaust system.
  • Disconnect the sensor's electrical connector.
  • Using the correct socket size, remove the EGT sensor from the exhaust pipe.
  • Install the new EGT sensor, threading it in by hand to avoid cross-threading.
  • Tighten the EGT sensor to the specified torque (typically 15-20 Nm) using the calibrated torque wrench.
  • Reconnect the sensor's electrical connector.
  • Reconnect the negative battery terminal.
  • Verify correct sensor operation with a scan tool.
View full procedure
Technical Service Bulletins

Oxygen Sensor Connector Corrosion

2012-06-15

Reports of corrosion on oxygen sensor connectors, leading to intermittent sensor readings or complete failure. This corrosion can affect the torque applied due to resistance on the connector.

2007-2011 Audi S5

Resolution: Inspect oxygen sensor connectors for corrosion. Clean or replace connectors as necessary. Apply dielectric grease before reconnecting. Ensure the sensor is properly torqued after addressing connector issues.

NOx Sensor Mounting Bracket Crack

2014-03-22

Certain NOx sensor mounting brackets have been found to crack due to vibration, leading to incorrect sensor readings or complete failure. The vibration can cause sensor bolts to loosen if not properly torqued.

2012-2016 Audi S5

Resolution: Inspect NOx sensor mounting bracket for cracks. Replace the bracket and sensor if damaged. Ensure the sensor and mounting bolts are properly torqued to manufacturer specifications to prevent future issues.

EGT Sensor Fault Due to Improper Torque

2015-11-01

EGT sensor failure has been observed when sensors are either over-torqued or under-torqued. Over-torquing can cause thread damage, while under-torquing may lead to vibration-related damage.

2007-2016 Audi S5

Resolution: Always torque EGT sensors to manufacturer specifications using a calibrated torque wrench. Replace any damaged sensors or exhaust components before 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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