Audi Audi S8 2012-2018 4.0L Engine Bolt Torque Specifications
Detailed bolt torque specifications for the 4.0L V8 TFSI engine found in the 2012-2018 Audi S8 (D4) generation. Includes torque values for critical engine components.
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
Engine Block
This section covers the torque specifications for the engine block and its internal components, including the crankshaft, connecting rods, oil system, and timing components.
1 Main Bearing Cap Bolts
M12
Main Bearing Cap Bolts
M12Important Notes
2 Connecting Rod Cap Bolts
M9
Connecting Rod Cap Bolts
M9Important Notes
3 Cylinder Head Bolts
M12
Cylinder Head Bolts
M12Important Notes
4 Oil Pan Bolts
M6
Oil Pan Bolts
M6Torque Value
Important Notes
5 Oil Pump Mounting Bolts
M8
Oil Pump Mounting Bolts
M8Torque Value
Important Notes
6 Timing Chain Tensioner Mounting Bolts
M6
Timing Chain Tensioner Mounting Bolts
M6Torque Value
Important Notes
7 Timing Chain Guide Bolts
M6
Timing Chain Guide Bolts
M6Torque Value
Important Notes
8 Crankshaft Pulley Bolt
M18
Crankshaft Pulley Bolt
M18Important Notes
Cylinder Heads Valvetrain
This section covers the torque specifications for the cylinder heads, camshafts, valve cover, and intake manifold.
1 Camshaft Bearing Cap Bolts
M7
Camshaft Bearing Cap Bolts
M7Important Notes
2 Valve Cover Bolts
M6
Valve Cover Bolts
M6Torque Value
Important Notes
3 Intake Manifold Bolts
M6
Intake Manifold Bolts
M6Torque Value
Important Notes
Exhaust System
This section covers the torque specifications for the exhaust manifold, downpipe, and clamps.
1 Exhaust Manifold to Cylinder Head Bolts
M8
Exhaust Manifold to Cylinder Head Bolts
M8Torque Value
Important Notes
2 Exhaust Downpipe to Manifold Flange Bolts
M10
Exhaust Downpipe to Manifold Flange Bolts
M10Torque Value
Important Notes
3 Exhaust System Clamps
N/A
Exhaust System Clamps
N/ATorque Value
Important Notes
Turbocharger System
This section covers the torque specifications for the turbochargers and their associated components.
1 Turbocharger Oil Inlet/Outlet Fittings
M10
Turbocharger Oil Inlet/Outlet Fittings
M10Torque Value
Important Notes
2 Turbocharger Mounting Bolts
M8
Turbocharger Mounting Bolts
M8Torque Value
Important Notes
3 Turbocharger Compressor Outlet/Inlet Bolts
M6
Turbocharger Compressor Outlet/Inlet Bolts
M6Torque Value
Important Notes
Cooling System
This section covers the torque specifications for the water pump, thermostat housing, coolant sensor, and hose clamps.
1 Water Pump Mounting Bolts
M6
Water Pump Mounting Bolts
M6Torque Value
Important Notes
2 Thermostat Housing Bolts
M6
Thermostat Housing Bolts
M6Torque Value
Important Notes
3 Coolant Hose Clamps
N/A
Coolant Hose Clamps
N/ATorque Value
Important Notes
4 Coolant Temperature Sensor Bolt
N/A
Coolant Temperature Sensor Bolt
N/ATorque Value
Important Notes
Other Components
This section covers the torque specifications for other components such as the starter, alternator, flywheel/flexplate, and engine mounts.
1 Starter Mounting Bolts
M10
Starter Mounting Bolts
M10Torque Value
Important Notes
2 Alternator Mounting Bolts
M10
Alternator Mounting Bolts
M10Torque Value
Important Notes
3 Flywheel/Flexplate Bolts
M10
Flywheel/Flexplate Bolts
M10Important Notes
4 Engine Mount Bolts
M12
Engine Mount Bolts
M12Important 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 it crucial to use the correct torque specifications?
Why is it crucial to use the correct torque specifications?
Using incorrect torque specifications can lead to a variety of problems. Under-torquing can result in loose fasteners, causing leaks, vibrations, and potentially component failure. Over-torquing can stretch or break bolts, strip threads in the aluminum engine block or heads (common on the 4.0L), and distort parts, leading to costly repairs. For example, over-torquing the intake manifold bolts can cause leaks and vacuum issues, affecting engine performance.
Q2 Do torque specifications change if I use aftermarket bolts or studs?
Do torque specifications change if I use aftermarket bolts or studs?
Yes, torque specifications provided are generally for OEM bolts. Aftermarket fasteners may have different tensile strengths and require different torque values. Always consult the fastener manufacturer's documentation for proper torque figures when using aftermarket parts. For example, high-strength aftermarket head studs will require torque values vastly different from stock.
Q3 What tools are needed to properly torque engine bolts?
What tools are needed to properly torque engine bolts?
A calibrated torque wrench is essential for accurate torque application. Using a basic wrench or tightening 'by feel' is not recommended for precision engine work. Additionally, you may need various sockets, extensions, and potentially torque angle gauges for certain components on the 4.0L, specifically the cylinder head bolts. Also, make sure you are using a torque wrench with the correct range for the specific bolt - don't use an inch-pound wrench for a foot-pound application.
Q4 Can I reuse old bolts?
Can I reuse old bolts?
Generally, some bolts are single-use and should be replaced each time they are removed. This is especially true for torque-to-yield (TTY) bolts, such as those used on the cylinder heads. Reusing TTY bolts can lead to incorrect clamping force and potential engine damage. For example, reusing a TTY head bolt increases the likelihood of head gasket failure.
Q5 What is the proper procedure for torque-to-yield (TTY) bolts?
What is the proper procedure for torque-to-yield (TTY) bolts?
TTY bolts require a specific torque process, often involving an initial torque value, followed by an additional angle of rotation (measured in degrees). These bolts stretch when tightened. Always follow the specific procedure listed in the Audi service manual. Deviating from this process, even slightly, can compromise the integrity of the seal or assembly. Failure to follow the correct sequence on cylinder head bolts could lead to a blown head gasket.
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 high-quality 1/2" drive torque wrench is essential for accurate tightening of engine bolts to specified torque values.
- Wide torque range (e.g., 20-200 Nm)
- Click-type mechanism for precise torque application
- Calibration certificate recommended
Torque Wrench (3/8" Drive)
A 3/8" drive torque wrench for smaller bolts and tighter areas in the engine bay.
- Lower torque range (e.g., 5-80 Nm)
- Click-type mechanism for precise torque application
- Calibration certificate recommended
Socket Set (Metric)
A comprehensive set of metric sockets in 1/2" and 3/8" drives is necessary for accessing various engine bolts.
- Wide range of metric sizes
- 6-point sockets for optimal grip
- Durable construction
Socket Extensions and Adapters
Various socket extensions and adapters facilitate reaching difficult-to-access bolts.
- Different lengths for variable access
- Swivel adapters for angled bolt heads
- Durable construction
Torx Socket Set
A set of Torx sockets, which are essential for tightening many engine bolts in the 4.0L engine.
- Complete set of common torx sizes
- Properly constructed for torque application
- Durable build quality
Service Procedures
Cylinder Head Bolt Tightening Procedure
Detailed instructions for correctly tightening cylinder head bolts on the 4.0L engine. Improper torque can lead to gasket failure.
- Clean all bolt threads and mating surfaces.
- Install new cylinder head bolts.
- Tighten all bolts in the correct sequence to the first torque specification
- Tighten all bolts in the correct sequence to the second torque specification
- Tighten all bolts in the correct sequence to the final angle specification
- Verify torque using a properly calibrated torque wrench.
Intake Manifold Bolt Tightening Procedure
Instructions for properly tightening the intake manifold bolts to avoid vacuum leaks. Specific sequence must be followed.
- Clean all bolt threads and mating surfaces.
- Install new intake manifold gasket.
- Position intake manifold and install all bolts loosely.
- Tighten all bolts in the correct sequence to the first torque specification
- Verify torque using a properly calibrated torque wrench.
Connecting Rod Bolt Tightening Procedure
Detailed procedure for tightening connecting rod bolts, which are critical for engine performance and reliability. Angle torque is usually required. Always use new bolts.
- Clean all bolt threads and mating surfaces.
- Install new connecting rod bolts.
- Apply appropriate lubricant to bolt threads
- Tighten all bolts in the correct sequence to the first torque specification
- Tighten all bolts in the correct sequence to the final angle specification
- Verify torque using a properly calibrated torque wrench.
Technical Service Bulletins
Excessive Oil Consumption in 4.0L TFSI Engines
2016-08-15Some 4.0L TFSI engines may exhibit higher-than-normal oil consumption due to issues with piston rings. This bulletin outlines a procedure to diagnose and address the problem.
Resolution: Replace the affected piston rings or in extreme cases, the complete piston assemblies. Follow factory torque specifications for all components during reassembly.
Timing Chain Tensioner Failure in 4.0L TFSI Engines
2017-05-01Certain 4.0L TFSI engines have experienced issues with timing chain tensioners, potentially leading to timing chain slippage and engine damage. Proper torque on replacement parts is essential.
Resolution: Inspect and replace the timing chain tensioners along with all associated guides and chains. Use proper torque specifications during reassembly, per the factory service manual.
Coolant Leakage from Thermostat Housing on 4.0L TFSI
2018-02-20A small number of 4.0L engines have developed coolant leaks from the thermostat housing, requiring new gaskets and fasteners. Following torque specifications is critical for a proper repair.
Resolution: Replace the thermostat housing gasket, and tighten all bolts to the factory recommended torque specifications in the proper sequence. Confirm leak-free seal.
About the Author
Expert automotive knowledge and experience
'/%3E%3Cpath d='M60 30a20 20 0 1 1 0 40 20 20 0 0 1 0-40zm0 45c16.5 0 30 7.5 30 16.8V100H30v-8.2c0-9.3 13.5-16.8 30-16.8z' fill='%23404040'/%3E%3C/svg%3E)
Diagnostic
Specialized in advanced diagnostic techniques using modern scan tools and oscilloscopes.
Repair
Expert in both traditional mechanical repairs and modern vehicle systems.
Additional Expertise
Documentation
Created over 500 detailed repair guides and technical documents.
Training
Conducted technical training sessions and contributed to repair databases.
Certifications & Research
Certifications
- ASE Master Technician Certification
- Advanced Diagnostic Specialist
- Hybrid/Electric Vehicle Systems
- Performance Tuning Expert
Research & Community
Actively researches emerging technologies and contributes to automotive forums.
Legal Disclaimer
Important information about using this content
Always refer to your vehicle's service manual and take appropriate safety precautions when performing any maintenance or repairs.
General Information
Warranty & Liability
The content on this website is provided "as is" without any representations or warranties, express or implied. We make no representations or warranties regarding the accuracy, completeness, or availability of the information.
We shall not be liable for any direct, indirect, special, or consequential damages arising from the use of information on this website.
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.