Audi Audi S6 2012-2018 4.0L Engine Bolt Torque Specifications & Fastener Values
Audi Audi S6 2012-2018

Audi Audi S6 2012-2018 4.0L Engine Bolt Torque Specifications

Comprehensive guide to the torque specifications for various bolts on the 4.0L V8 TFSI engine found in the 2012-2018 Audi S6 (C7) model. Includes values for critical engine components and fasteners.

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

Cylinder Head

Specifications for bolts securing the cylinder head to the engine block. Critical for sealing and engine performance.

1

Cylinder Head Bolts (Main)

M12 x 1.5
Important Notes
Use a new set of bolts. Follow the specific torque sequence as per the repair manual. Angle tightening must be performed with a calibrated angle meter or torque wrench capable of measuring angles.
2

Cylinder Head Side Bolts

M10 x 1.5
Torque Value
18 ft-lbs (25 N·m)
Important Notes
These bolts secure the sides of the cylinder head. Ensure even tightening.

Intake System

Torque specifications for components of the intake system, ensuring proper sealing and air flow.

1

Intake Manifold Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Tighten bolts in a cross pattern to ensure even pressure. Avoid over-tightening, which can cause leaks.
2

Throttle Body Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Tighten bolts evenly. Do not overtighten to prevent damage to throttle body.

Exhaust System

Specifications for securing exhaust components, critical for sealing and preventing leaks.

1

Exhaust Manifold Bolts/Nuts to Cylinder Head

M8 x 1.25
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Ensure proper torque to prevent leaks. Check for even contact with the cylinder head.
2

Exhaust Downpipe Bolts to Turbo

M8 x 1.25
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Ensure proper torque to prevent exhaust leaks. Use appropriate high-temp fasteners.
3

Exhaust Clamp Bolts

M8 x 1.25
Torque Value
30 ft-lbs (40 N·m)
Important Notes
Tighten bolts evenly to secure exhaust pipes. Avoid over-tightening, which can cause leaks.

Turbocharger System

Torque specifications for turbocharger mounting and oil lines, ensuring proper function and leak prevention.

1

Turbocharger Oil Feed Line Bolt

M10 x 1.0
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Use new sealing washers. Overtightening will damage the oil line and cause leaks. Ensure all connections are clean and threads are smooth.
2

Turbocharger Oil Drain Line Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Use new gaskets if required. Ensure the drain line is properly seated before tightening.
3

Turbocharger Mounting Bolts to Manifold

M10 x 1.5
Torque Value
30 ft-lbs (40 N·m)
Important Notes
Ensure even tightening to prevent leaks and proper turbo alignment.

Engine Block

Specifications for critical fasteners within the engine block, ensuring proper internal engine operation.

1

Main Bearing Cap Bolts

M12 x 1.5
Important Notes
Use new bolts. Follow the specific torque sequence. Angle tightening is critical for proper bearing cap clamping.
2

Connecting Rod Cap Bolts

M9 x 1.0
Important Notes
Use new bolts. Follow the correct torque sequence. Angle tightening is crucial for rod bearing function.
3

Engine Mount Bolts to Engine Block

M12 x 1.75
Torque Value
35 ft-lbs (47 N·m)
Important Notes
Ensure proper alignment of engine mounts. Check for proper seating.

Oil System

Specifications for bolts in the oil system, critical for preventing leaks and maintaining proper lubrication.

1

Oil Pan Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Tighten bolts in a cross pattern to prevent leaks. Do not overtighten.
2

Oil Pump Mounting Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Ensure pump is correctly seated before tightening. Estimated value.
3

Oil Filter Housing Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Ensure the housing is correctly aligned before tightening. Estimated value.
4

Oil Drain Plug

M14 x 1.5
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Use a new crush washer. Do not overtighten to avoid damaging the oil pan.

Cooling System

Specifications for bolts in the cooling system, essential for maintaining proper engine temperature.

1

Water Pump Mounting Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Ensure proper alignment. Use new gasket if required. Estimated value.
2

Thermostat Housing Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Use a new gasket. Tighten evenly. Estimated value.

Accessory Drive

Torque specifications for bolts securing accessory components such as the alternator, power steering pump, and A/C compressor.

1

Alternator Mounting Bolts

M10 x 1.5
Torque Value
30 ft-lbs (40 N·m)
Important Notes
Ensure proper alignment. Estimated value.
2

Power Steering Pump Mounting Bolts

M8 x 1.25
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Ensure the pump is seated flush to the mounting bracket. Estimated value.
3

A/C Compressor Mounting Bolts

M8 x 1.25
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Ensure the compressor is properly seated. Estimated value.
4

Crankshaft Pulley Bolt

M14 x 1.5
Important Notes
Use a new bolt. Angle tightening is critical for proper pulley mounting and engine operation.

Other Critical Fasteners

Specifications for other critical fasteners like flywheel/flexplate, starter, and transmission bellhousing bolts.

1

Flywheel/Flexplate Bolts

M10 x 1.0
Important Notes
Use new bolts. Follow the specific torque sequence. Angle tightening ensures proper clamping force.
2

Starter Mounting Bolts

M10 x 1.5
Torque Value
35 ft-lbs (47 N·m)
Important Notes
Ensure proper seating of the starter. Do not overtighten.
3

Transmission Bellhousing Bolts to Engine

M12 x 1.75
Torque Value
45 ft-lbs (60 N·m)
Important Notes
Ensure proper alignment. Bolts should be tightened evenly to maintain alignment.

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 are precise torque specifications important for the 4.0L engine?

Precise torque specifications are critical to ensure proper clamping force, preventing leaks, and avoiding component damage. Over-tightening can strip threads or warp components, while under-tightening can lead to leaks or loosening due to vibration. For the 4.0L TFSI, complex components such as the turbochargers, oil pump, and cylinder heads, require accurate torque application for optimal performance and longevity.

Q2

What happens if I over-torque a bolt on the 4.0L engine?

Over-torquing can damage bolts by exceeding their yield strength, potentially leading to thread stripping, bolt breakage, or component warping. For instance, over-tightening a cylinder head bolt can cause head gasket failure or distortion of the cylinder head itself, requiring costly repairs. Similarly, overtightening the turbocharger oil and coolant line fittings could crack the fitting or cause leaks.

Q3

Can I reuse torque-to-yield bolts on the 4.0L engine?

No, torque-to-yield (TTY) bolts, often used for critical components like cylinder heads and connecting rods on the 4.0L, are designed for one-time use. These bolts stretch when properly torqued and must be replaced after being loosened. Reusing them can result in incorrect clamping force and potential engine damage. Always refer to the service manual for bolt replacement guidelines.

Q4

How do I ensure accurate torque when working on the 4.0L engine?

Use a calibrated torque wrench and always follow the manufacturer's torque specifications. Verify the wrench calibration periodically. It's also important to tighten bolts in the recommended sequence to distribute clamping force evenly. For example, when tightening a cylinder head, follow the specified tightening pattern in steps to prevent warping.

Q5

Are torque specs different between the various S6 model years using the 4.0L?

While there may be minor variations, the core torque specifications for the major engine components (cylinder head, crankshaft, connecting rods, etc.) on the 4.0L TFSI engines used across 2012-2018 S6 models generally remain consistent. However, always consult the specific repair manual for the exact model year of your vehicle to confirm the correct specs.

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 (1/2" Drive)

A 1/2" drive torque wrench is essential for accurately tightening larger bolts to the specified torque values.

  • Wide torque range
  • Accurate calibration
  • Durable construction
Learn more

Torque Wrench (3/8" Drive)

A 3/8" drive torque wrench is suitable for smaller bolts and components that require less torque.

  • Precise torque settings
  • Compact size for access
  • Reliable performance
Learn more

Socket Set (Metric)

A comprehensive metric socket set is required for accessing and tightening various bolts on the 4.0L engine.

  • Variety of socket sizes
  • Durable construction
  • Standard and deep sockets
Learn more

Extension Bars

Extension bars are useful for reaching bolts that are located in recessed or difficult-to-access areas of the engine.

  • Various lengths for flexibility
  • Secure attachment to sockets
  • Durable materials
Learn more

Torx Socket Set

A set of Torx sockets is necessary for specific bolts used on the 4.0L engine.

  • Variety of sizes
  • High quality
  • Precision fit
Learn more
Service Procedures

Cylinder Head Bolt Tightening Procedure

This procedure outlines the correct sequence and torque specifications for tightening the cylinder head bolts on the 4.0L engine.

  • Clean threads of bolts and cylinder block
  • Install new cylinder head bolts
  • Tighten all bolts in sequence to 40 Nm (30 lb-ft)
  • Tighten all bolts in sequence an additional 90 degrees
  • Tighten all bolts in sequence another 90 degrees
  • Check bolts one final time after 10 minutes
View full procedure

Intake Manifold Bolt Tightening Procedure

This procedure outlines the correct sequence and torque specifications for tightening the intake manifold bolts on the 4.0L engine.

  • Clean mating surfaces of intake manifold and cylinder head
  • Install intake manifold with new gasket
  • Tighten all bolts in sequence to 10 Nm (7.4 lb-ft)
  • Tighten all bolts in sequence an additional 90 degrees
View full procedure

Oil Pan Bolt Tightening Procedure

This procedure outlines the correct sequence and torque specifications for tightening the oil pan bolts on the 4.0L engine.

  • Clean mating surfaces of oil pan and engine block
  • Install oil pan with new gasket
  • Tighten all bolts in sequence to 25 Nm (18.5 lb-ft)
View full procedure

Turbocharger Mounting Bolt Tightening Procedure

This procedure outlines the correct sequence and torque specifications for tightening the turbocharger mounting bolts on the 4.0L engine.

  • Clean mating surfaces
  • Install turbocharger with new gasket
  • Tighten all bolts to 30 Nm (22 lb-ft)
View full procedure
Technical Service Bulletins

Oil Leakage from Oil Pan

2015-03-15

Some vehicles may experience oil leakage from the oil pan due to improper bolt torque. Ensure bolts are tightened to the correct specifications as outlined in the service procedure. New bolts and gaskets may be needed.

2012-2015

Resolution: Replace oil pan gasket and oil pan bolts. Tighten all bolts to 25 Nm (18.5 lb-ft).

Cylinder Head Bolt Stretch Issue

2017-07-20

A small number of vehicles have been found to have cylinder head bolt stretch issues leading to head gasket failure. Proper tightening procedure must be followed closely and all bolts must be replaced on each removal of cylinder head.

2016-2018

Resolution: Replace all cylinder head bolts upon every removal. Follow proper tightening sequence and torque specifications.

Intake Manifold Gasket Leakage

2016-11-01

Intake manifold leaks caused by improperly tightened intake manifold bolts or a faulty gasket. Inspect carefully and tighten to specifications with new gasket.

2012-2016

Resolution: Replace intake manifold gasket and ensure bolts are tightened to the correct torque specifications in the correct sequence.

About the Author

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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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  • All specifications, including torque values, fluid capacities, and maintenance procedures, should be verified against your vehicle's factory service manual.
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