BMW M5 2018-present Exhaust System Bolt Torque Specifications
This page provides detailed torque specifications for exhaust bolts on the 2018-Present BMW M5 (F90) generation. Includes specifications for various exhaust 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
Exhaust Manifold
Specifications for bolting the exhaust manifolds (headers) to the cylinder head and exhaust pipes.
1 Exhaust Manifold to Cylinder Head Bolts
M8 x 1.25
Exhaust Manifold to Cylinder Head Bolts
M8 x 1.25Important Notes
2 Exhaust Pipe to Exhaust Manifold/Header Bolts
M10 x 1.5
Exhaust Pipe to Exhaust Manifold/Header Bolts
M10 x 1.5Torque Value
Important Notes
Catalytic Converter
Specifications for bolting the catalytic converter to the exhaust pipes.
1 Catalytic Converter to Exhaust Pipe Bolts
M10 x 1.5
Catalytic Converter to Exhaust Pipe Bolts
M10 x 1.5Torque Value
Important Notes
Muffler
Specifications for bolting the muffler to the exhaust pipes.
1 Muffler to Exhaust Pipe Bolts
M10 x 1.5
Muffler to Exhaust Pipe Bolts
M10 x 1.5Torque Value
Important Notes
Clamps
Specifications for tightening exhaust system clamps, such as band clamps or U-bolt clamps.
1 Exhaust System Band Clamps
M8 x 1.25
Exhaust System Band Clamps
M8 x 1.25Torque Value
Important Notes
2 Exhaust System U-Bolt Clamps
M8 x 1.25
Exhaust System U-Bolt Clamps
M8 x 1.25Torque Value
Important Notes
Sensors
Specifications for installing oxygen sensors into the exhaust system.
1 Oxygen Sensor
M18 x 1.5
Oxygen Sensor
M18 x 1.5Torque Value
Important Notes
Hangers
Specifications for bolting exhaust hangers to the chassis and exhaust system.
1 Exhaust Hanger Bolts/Nuts
M8 x 1.25
Exhaust Hanger Bolts/Nuts
M8 x 1.25Torque Value
Important Notes
Heat Shields
Specifications for bolting heat shields to the chassis and exhaust system.
1 Heat Shield Bolts/Nuts
M6 x 1.0
Heat Shield Bolts/Nuts
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 is using the correct torque specification for exhaust bolts important?
Why is using the correct torque specification for exhaust bolts important?
Using the correct torque specification is crucial to prevent exhaust leaks, component damage, and potential safety hazards. Under-tightening can lead to leaks and rattling, while over-tightening can damage threads, crush gaskets, or even crack exhaust components. Proper torque ensures a secure, leak-free seal and optimal performance. For example, if the downpipe bolts are not torqued correctly, the exhaust gasses will leak from that area, which could result in a loss of performance and potential damage to other components due to high heat.
Q2 What happens if I over-tighten exhaust bolts?
What happens if I over-tighten exhaust bolts?
Over-tightening exhaust bolts can cause several issues. It can strip the threads on the bolt or the exhaust component itself, leading to costly repairs. It can also crush the exhaust gaskets, rendering them ineffective and causing leaks. In extreme cases, over-tightening can even crack or deform exhaust flanges or manifolds. For instance, over-tightening the bolts connecting the mid-pipe to the muffler can lead to a damaged flange, which will need to be replaced.
Q3 Can I reuse exhaust gaskets?
Can I reuse exhaust gaskets?
It is generally not recommended to reuse exhaust gaskets. Exhaust gaskets are designed to crush and form a seal when torqued to the proper specification. Once compressed, they typically do not provide an effective seal again when reused. Reusing them can lead to leaks and require further work. For example, when replacing a cat-back exhaust, using old gaskets often leads to exhaust leaks that require additional time to correct.
Q4 Do I need to use anti-seize on exhaust bolts?
Do I need to use anti-seize on exhaust bolts?
Yes, applying a high-temperature anti-seize compound to exhaust bolts is strongly recommended. Exhaust systems experience high temperatures and are exposed to the elements, which can lead to corrosion and seizing. Anti-seize helps prevent bolts from seizing and makes future removal much easier. This can save time and prevent damage to components during future service. For example, neglecting anti-seize on the bolts connecting the exhaust to the engine downpipes will cause the bolts to become very difficult to remove and may even require cutting them off.
Q5 How often should I check my exhaust bolts?
How often should I check my exhaust bolts?
It is a good practice to inspect exhaust bolts periodically, especially after major temperature fluctuations, or aggressive driving. Check for leaks, loose bolts and any signs of damage. Generally, an inspection during routine maintenance checks or oil changes is sufficient. However, you may want to check them more frequently if you notice any unusual noises or performance issues.
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 applying the correct torque to exhaust bolts, preventing over-tightening or under-tightening.
- Adjustable torque settings
- Click-type mechanism for accurate torque application
13mm Socket
A standard 13mm socket is needed to fit the exhaust bolts on the BMW M5 F90.
- 6-point design for secure grip
- Durable construction
16mm Socket
A 16mm socket, typically shallow, will help access various parts of the exhaust system
- 6-point design for secure grip
- Durable construction
Extensions
Various length extensions and universal joints to access the exhaust bolts and nuts in difficult locations.
- Multiple lengths for varying access requirements
- Universal joint for angular access
Service Procedures
Exhaust System Bolt Tightening Procedure
This procedure outlines the steps for correctly tightening the exhaust bolts on a 2018-Present BMW M5 (F90).
- Locate all exhaust bolts (Typically between manifolds and downpipe, downpipe to midpipe, midpipe to muffler)
- Consult a reliable source for the correct torque specifications for each bolt location (These may vary)
- Using the appropriate sized socket, manually thread the bolts to an initial snug point.
- Using a calibrated torque wrench, torque each bolt to the specified torque in the correct order (Often alternating and tightening gradually)
- After tightening to specified torque, re-inspect for any leaks and re-torque if necessary
Exhaust System Bolt Removal Procedure
This procedure outlines the steps for correctly removing the exhaust bolts on a 2018-Present BMW M5 (F90).
- Spray penetrating fluid on the bolts/nuts.
- Using the correct size socket, begin to loosen each bolt or nut.
- Note the condition of the bolt for replacement upon installation.
- Keep bolts in order by which they were removed for ease of installation.
- After loosening each bolt, remove from the exhaust system.
Technical Service Bulletins
Exhaust Bolt Corrosion and Replacement
2021-05-15Some instances of exhaust bolt corrosion have been noted, especially in areas with harsh winter conditions. This bulletin recommends checking bolts and replacing as needed to prevent leaks.
Resolution: Inspect exhaust bolts for corrosion or damage, replace with new OE bolts if corrosion or damage is noted. Ensure proper torque is applied.
Exhaust Clamps Loosening Prematurely
2022-09-22Some reports of exhaust clamps prematurely loosening. This issue may be caused by improper installation or bolt stretch. Re-torque all clamps and exhaust bolts.
Resolution: Inspect all clamps and exhaust bolts, tighten to correct specification, consider replacing bolts/clamps in necessary.
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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.