Audi Audi S5 2017-present Fuel System Bolt Torque Specifications & Line Fittings
Audi Audi S5 2017-present

Audi Audi S5 2017-present Fuel System Bolt Torque Specifications

This page provides detailed torque specifications for fuel system bolts on the 2017-present Audi S5, including fuel pump, fuel rail, and injector 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

Fuel Tank And Components

Torque specifications for components related to the fuel tank, including straps, filler neck, access panels, the fuel pump module, and fuel level sensors.

1

Fuel Tank Strap Bolts

M8 x 1.25
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Secures the fuel tank to the vehicle chassis. Under-torquing can lead to tank movement and damage; over-torquing can damage straps or the chassis.
2

Fuel Tank Filler Neck Bolts

M6 x 1.0
Torque Value
11 ft-lbs (15 N·m)
Important Notes
Connects the fuel filler neck to the vehicle body. This bolt is important for proper sealing of the filler neck area.
3

Fuel Tank Access Panel Screws/Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Secures the access panel for the fuel pump assembly. Over-torquing can damage plastic panel or threads. Estimated value.
4

Fuel Pump Module Retaining Ring

Special Tool Required
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Secures the fuel pump assembly to the fuel tank. Critical for proper sealing and prevention of fuel leaks. Overtightening can break or crack the plastic fuel tank. Use specific tool for proper torque application. Estimated value.
5

Fuel Level Sensor Bolts/Screws

M4 x 0.7
Torque Value
4 ft-lbs (5 N·m)
Important Notes
Secures fuel level sending unit. Low torque to prevent damage to delicate components. Estimated value.

Fuel Lines And Rail

Torque specifications for components in the fuel delivery system, including the high-pressure fuel pump, fuel lines, fuel rail, and fuel injectors.

1

High-Pressure Fuel Pump Mounting Bolts

M8 x 1.25
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Securely mounts the high-pressure fuel pump to the engine. Critical for proper pump function and preventing fuel leaks.
2

High-Pressure Fuel Line Banjo Bolt (Pump Side)

M12 x 1.5
Torque Value
20 ft-lbs (27 N·m)
Important Notes
Secures the high-pressure line to the pump outlet. Proper torque is critical for sealing the fuel at high pressures and preventing leaks. Use new crush washers.
3

High-Pressure Fuel Line Banjo Bolt (Fuel Rail Side)

M12 x 1.5
Torque Value
20 ft-lbs (27 N·m)
Important Notes
Secures the high-pressure line to the fuel rail. Proper torque is critical for sealing the fuel at high pressures and preventing leaks. Use new crush washers.
4

Fuel Rail Mounting Bolts

M6 x 1.0
Torque Value
15 ft-lbs (20 N·m)
Important Notes
Attaches fuel rail to the intake manifold or cylinder head. Proper torque ensures proper injector alignment and fuel delivery.
5

Fuel Injector Rail Mounting Bolts/Screws

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Hold the injector fuel rails to the cylinder head. Critical to avoid fuel leaks. Low torque is due to materials involved. Estimated value.
6

Fuel Injector Retaining Clips/Bolts

M4 x 0.7
Torque Value
4 ft-lbs (5 N·m)
Important Notes
If injectors use clips or small bolts, then low torque is essential to avoid damage. Often these are small screws or clips that require little tightening. Estimated value.
7

Fuel Pressure Sensor Mounting Bolt/Screw

M5 x 0.8
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Secures the pressure sensor, preventing damage to the sensor and ensuring a secure connection for accurate readings. Usually a small bolt or screw. Estimated value.
8

Low-Pressure Fuel Line Quick Connect Fittings

N/A
Torque Value
0 ft-lbs (0 N·m)
Important Notes
Quick connect fittings generally do not have a torque specification, but proper engagement needs to be ensured.
9

Fuel Filter Mounting Bolts/Bracket

M8 x 1.25
Torque Value
18 ft-lbs (24 N·m)
Important Notes
Secures the fuel filter to the chassis. Ensures that the filter doesn't move during operation.

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 using the correct torque specification crucial for fuel system bolts?

Using the correct torque ensures a proper seal, preventing fuel leaks, which are a significant fire hazard. Under-tightening can lead to leaks, while over-tightening can damage the threads or the component itself, potentially causing fuel system failure.

Q2

What happens if I overtighten a fuel system bolt?

Overtightening can stretch or break bolts, damage the threads in the component, or crush sealing washers and gaskets. This can lead to leaks, difficult removal in the future, and even component failure. For example, over-tightening a fuel line banjo bolt can crush the copper washers, leading to a leak.

Q3

Do I need to replace fuel system bolts when working on the fuel system?

It's best practice to replace fuel system bolts and sealing washers, especially those related to high pressure fuel lines, when working on the fuel system. These bolts can be torque-to-yield and designed for single-use. Reusing them could compromise sealing and clamping force.

Q4

What type of torque wrench should I use for these specifications?

A calibrated torque wrench, preferably a 1/4" or 3/8" drive, is recommended. A beam style wrench or digital torque wrench can be used, as long as the torque range covers your application. Avoid using an impact gun as it's very easy to overtighten fasteners

Q5

Where can I find the exact torque specifications if I am unsure?

Always refer to the official Audi repair manual specific to your 2017-Present S5 model. Torque specifications can vary between model years and sub-assemblies. Consulting an official service manual will always be the most accurate source for your specific vehicle.

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 fuel system bolts to the specified torque values. Choose a wrench with a range that covers the required values (typically 5-30 Nm).

  • Accurate torque application
  • Click-type or digital
  • Appropriate drive size for sockets
Learn more

Socket Set (Metric)

A metric socket set with sizes ranging from 8mm to 13mm is required for the various fuel system bolts and fittings. A deep socket set is recommended.

  • Metric sizes for Audi vehicles
  • Shallow and deep socket options
  • Various drive sizes (1/4" or 3/8")
Learn more

Torx Bit Set

A Torx bit set is needed for specific bolts used within the fuel system of the B9 S5. Sizes T25, T27 and T30 are common

  • Various torx sizes
  • Durable construction
  • Often compatible with socket drive
Learn more

Extension Bars

Extension bars of various lengths are useful for accessing hard-to-reach bolts within the fuel system.

  • Various lengths
  • Improved accessibility
  • Compatible with socket drive
Learn more
Service Procedures

High-Pressure Fuel Pump Mounting Bolt Torque

This procedure details the torque specification for the high-pressure fuel pump mounting bolts on the 2017-Present Audi S5 3.0 TFSI engine.

  • Locate the mounting bolts securing the high-pressure fuel pump to the engine.
  • Using the appropriate socket, tighten each bolt to 25 Nm (18 ft-lbs).
  • Verify torque with a calibrated torque wrench.
View full procedure

Fuel Rail Pressure Sensor Torque

This procedure outlines the torque specification for the fuel rail pressure sensor on the 2017-Present Audi S5 3.0 TFSI engine.

  • Locate the fuel rail pressure sensor.
  • Using the appropriate socket, tighten the sensor to 10 Nm (7 ft-lbs).
  • Ensure proper seating and sealing of the sensor.
View full procedure

Fuel Line Connection Torque

This procedure details the torque procedure for fuel line connections at the rail and pump.

  • Locate the fuel line connections at the fuel pump and rail
  • Using the appropriate wrench or socket, tighten to 22 Nm (16 ft-lbs).
  • Check for proper sealing and leaks.
View full procedure
Technical Service Bulletins

Potential Fuel Leak Due to Improper Torque

2020-06-15

This bulletin addresses reported fuel leaks due to improper torque of high-pressure fuel pump mounting bolts and fuel line connections. Under or over tightening can cause leaks, component damage or premature failure.

2017-2020 Audi S5

Resolution: Verify all fuel system bolts are tightened to the specified torque. If leaks are present, replace the affected components and properly torque the new parts per service manual.

Fuel Pressure Sensor Connector Corrosion

2021-02-20

Corrosion can occur within the fuel pressure sensor connector due to improper sealing. This bulletin addresses this potential issue and proper tightening of the sensor to prevent the ingress of moisture.

2017-2021 Audi S5

Resolution: Inspect sensor connectors for corrosion. If present, replace the connector and sensor. Ensure the sensor is properly tightened to 10 Nm (7 ft-lbs) to ensure proper sealing.

Updated Fuel Pump Bolt Material

2022-11-10

This bulletin announces a change in the bolt material used in the high pressure fuel pump. The torque specification remains the same but using the updated bolt is recommended for improved durability and sealing

2017-2022 Audi S5

Resolution: Use the updated bolts during any fuel pump maintenance or replacement. Torque to 25 Nm (18 ft-lbs)

About the Author

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Alan Montanye - Automotive Technical Specialist
ASE

Alan Montanye

Automotive Technical Specialist

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