Acura NSX 2016-present Exhaust System Bolt Torque Specifications
Comprehensive guide to the exhaust bolt torque specifications for the 2016-present Acura NSX, including all relevant fasteners and stages.
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
Bolts and studs securing the exhaust manifold to the engine cylinder head and block.
1 Exhaust Manifold Bolts
M10 x 1.5
Exhaust Manifold Bolts
M10 x 1.5Torque Value
Important Notes
2 Exhaust Manifold Studs
M12 x 1.75
Exhaust Manifold Studs
M12 x 1.75Torque Value
Important Notes
Downpipe and catalytic converter
Bolts connecting the downpipe to the exhaust manifold and catalytic converter.
1 Downpipe Bolts
M10 x 1.5
Downpipe Bolts
M10 x 1.5Torque Value
Important Notes
2 Catalytic Converter Bolts
M12 x 1.75
Catalytic Converter Bolts
M12 x 1.75Torque Value
Important Notes
Muffler and tailpipe
Bolts securing the muffler hanger to the vehicle's frame and tailpipe to the muffler.
1 Muffler Hanger Bolts
M8 x 1.25
Muffler Hanger Bolts
M8 x 1.25Torque Value
Important Notes
2 Tailpipe Bolts
M10 x 1.5
Tailpipe Bolts
M10 x 1.5Torque Value
Important Notes
Heat shield
Bolts securing the heat shield to the exhaust system.
1 Heat Shield Bolts
M6 x 1.0
Heat Shield Bolts
M6 x 1.0Torque 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 are proper exhaust bolt torque specifications important?
Why are proper exhaust bolt torque specifications important?
Proper torque is critical for ensuring a leak-free exhaust system and preventing damage to the components. Overtightening can lead to stripped threads, broken bolts, and warped flanges, resulting in leaks and potential exhaust system failure. Undertightening can also cause leaks and vibration issues. Correct torque ensures proper sealing and longevity.
Q2 What happens if I overtighten the exhaust bolts?
What happens if I overtighten the exhaust bolts?
Overtightening exhaust bolts can cause several issues including: stripping the threads in the manifold or exhaust component, breaking bolts, distorting the flange, causing exhaust leaks, and making future disassembly difficult. For example, a heavily overtightened manifold bolt might snap during removal, requiring a more complicated extraction process.
Q3 What happens if I undertighten the exhaust bolts?
What happens if I undertighten the exhaust bolts?
Undertightened exhaust bolts can lead to exhaust leaks, which can be dangerous due to carbon monoxide poisoning. They can also cause vibrations that lead to premature wear and potential damage of the exhaust system and surrounding components, such as heat shields and body panels. You may hear a hissing or chugging noise under acceleration when an exhaust leak is present.
Q4 Should I use new gaskets or washers when reinstalling exhaust components?
Should I use new gaskets or washers when reinstalling exhaust components?
Yes, it is highly recommended to use new gaskets and washers whenever reassembling exhaust components. Gaskets are designed to provide a proper seal and are often crushed or deformed after being torqued. Reusing them can lead to leaks and improper sealing. New washers also help ensure the bolt is properly tensioned and prevent slippage.
Q5 Do I need to retorque the exhaust bolts after installation?
Do I need to retorque the exhaust bolts after installation?
Yes, it's a good practice to retorque exhaust bolts after a short period of use, typically after a heat cycle. This is because the materials expand as they heat up and may settle slightly, which can cause the initial torque to loosen. A check after the first drive or 100 miles of use is recommended.
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
A calibrated torque wrench is essential for accurately tightening exhaust bolts to the manufacturer's specifications, preventing damage and ensuring proper sealing.
- Click-type or digital
- Accurate within the required torque range
Socket Set
A set of sockets in various sizes is needed to fit the exhaust flange and mounting bolts.
- Metric sizes
- 6-point sockets for better grip
Extension Bars
Extension bars can help reach recessed or hard-to-access exhaust bolts.
- Various lengths for flexibility
- Durable construction
Universal Joint
A universal joint allows access to bolts at angles, which may be necessary on the exhaust system.
- Flexible rotation
- Durable construction
Service Procedures
Exhaust Manifold Bolt Torque Procedure
This procedure outlines how to properly torque the exhaust manifold bolts on a 2016-Present Acura NSX.
- Locate the exhaust manifold flange bolts.
- Ensure the threads on the bolts and in the cylinder head are clean.
- Install the manifold with new gaskets and loosely thread bolts
- Tighten all manifold bolts in a criss-cross pattern using the sequence outlined in the service manual
- Torque the bolts to 27 Nm (20 ft-lbs) using a calibrated torque wrench.
Exhaust Flange Connection Torque Procedure
This procedure outlines how to properly torque the bolts on the exhaust flanges downstream from the manifold.
- Locate the exhaust flange bolts at each connection point.
- Ensure the mating surfaces of the flanges are clean and free of debris.
- Install a new gasket between the flanges, and loosely thread the bolts
- Tighten all bolts evenly using the sequence outlined in the service manual
- Torque all bolts at each flange to 45 Nm (33 ft-lbs) using a calibrated torque wrench.
- Inspect for any leaks after installation
Exhaust System Hanger Bolt Torque Procedure
This procedure outlines how to properly torque the bolts on the exhaust hangers and brackets.
- Locate the bolts securing the exhaust hangers to the chassis.
- Ensure the bolts are clean
- Install all bolts loosely to align the system
- Tighten all hanger bolts using the torque specification of 22 Nm (16 ft-lbs) using a calibrated torque wrench
- Check all bolts are secure and the exhaust system is properly aligned.
Technical Service Bulletins
Exhaust Gasket Leakage Issues
2018-05-10Some 2016-2018 NSX models may experience exhaust leaks due to inadequate sealing of the exhaust manifold gasket.
Resolution: Inspect and replace the exhaust manifold gasket. Ensure all bolts are torqued to the correct specifications of 27 Nm (20 ft-lbs) in the correct order. Use genuine Acura parts for best results. Retorque after a short drive.
Exhaust Flange Bolt Corrosion
2020-09-22Reports of corrosion on the exhaust flange bolts are noted in certain regions, potentially leading to improper clamping force.
Resolution: Inspect all exhaust flange bolts for signs of corrosion. Replace corroded bolts and gaskets using genuine Acura parts. Torque all bolts to 45 Nm (33 ft-lbs). Apply anti-seize to the threads of replacement bolts
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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.