BMW 340i 2005-2011 Exhaust System Bolt Torque Specifications
This page provides detailed torque specifications for exhaust bolts on the 2005-2011 BMW 3 Series (E90, E91, E92, E93) models, including downpipe, midpipe, and muffler connections.
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 bolts securing the exhaust manifold or headers to the cylinder head and connecting to the exhaust piping.
1 Exhaust Manifold to Cylinder Head Bolts
M8 x 1.25
Exhaust Manifold to Cylinder Head Bolts
M8 x 1.25Torque Value
Important 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
Torque specifications for the bolts connecting the catalytic converter to the exhaust pipe.
1 Catalytic Converter to Exhaust Pipe Bolts
M10 x 1.5
Catalytic Converter to Exhaust Pipe Bolts
M10 x 1.5Torque Value
Important Notes
Exhaust Piping
Torque specifications for bolts at flange connections within the exhaust system.
1 Exhaust Flange Bolts
M8 x 1.25
Exhaust Flange Bolts
M8 x 1.25Torque Value
Important Notes
2 Muffler to Exhaust Pipe Bolts
M10 x 1.5
Muffler to Exhaust Pipe Bolts
M10 x 1.5Torque Value
Important Notes
Exhaust Hangers
Specifications for bolts and nuts securing the exhaust hangers to the chassis.
1 Exhaust Hanger Bolts/Nuts
M8 x 1.25
Exhaust Hanger Bolts/Nuts
M8 x 1.25Torque Value
Important Notes
Oxygen Sensors
Torque specifications for oxygen sensors, which are threaded components in the exhaust system.
1 Oxygen Sensor (O2 Sensor)
M18 x 1.5
Oxygen Sensor (O2 Sensor)
M18 x 1.5Torque Value
Important Notes
V Band Clamps
Specifications for bolts on V-Band clamps used to join exhaust piping.
1 Exhaust V-Band Clamp Bolt
M6 x 1.0
Exhaust V-Band Clamp Bolt
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 What are the correct torque specifications for the exhaust manifold bolts on a 2005-2011 BMW 340i?
What are the correct torque specifications for the exhaust manifold bolts on a 2005-2011 BMW 340i?
The exhaust manifold bolts for the 2005-2011 BMW 340i (assuming a typo and you mean 335i since the 340i is a newer model) typically require a torque specification of 22 Nm (16 ft-lb). However, always refer to your specific vehicle's service manual for exact values as variations can exist.
Q2 What about the torque specs for the exhaust downpipe bolts?
What about the torque specs for the exhaust downpipe bolts?
Downpipe bolts on a 2005-2011 BMW 335i generally require around 35 Nm (26 ft-lb). Again, consulting your vehicle's specific repair manual is highly recommended, and the torque might vary slightly based on the type of connection.
Q3 Are the exhaust clamp torque specifications different from the manifold or downpipe bolts?
Are the exhaust clamp torque specifications different from the manifold or downpipe bolts?
Yes, exhaust clamps usually have different, often lower, torque specifications. For exhaust clamps, a common range is 20-25 Nm (15-18 ft-lb), but this varies widely depending on the clamp type and size. Check your service manual or the clamp manufacturer’s specifications for exact details. Overtightening can damage the clamp or pipe.
Q4 What if I don't have a torque wrench?
What if I don't have a torque wrench?
While it is strongly recommended to use a torque wrench for accurate tightening, in a pinch, you can carefully tighten the bolt until it feels snug then give it about a 1/4 turn with a standard wrench. This is a very inaccurate method and can lead to leaks or damage, so this is highly discouraged. Get a torque wrench.
Q5 Should I use anti-seize on exhaust bolts?
Should I use anti-seize on exhaust bolts?
Yes, applying a thin layer of high-temperature anti-seize to the threads of exhaust bolts is highly recommended. This prevents bolts from seizing due to heat and corrosion, making future removal easier. Be careful not to apply anti-seize to the bolt heads or flanges as this can cause incorrect torque.
Q6 Do I need to replace exhaust gaskets when reassembling the exhaust system?
Do I need to replace exhaust gaskets when reassembling the exhaust system?
Yes, it is crucial to replace exhaust gaskets whenever you disassemble the exhaust system. Old gaskets can become compressed, hardened, or damaged, which leads to exhaust leaks and reduced performance. Ensure you use gaskets specified for your vehicle.
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 calibrated torque wrench is essential for accurately tightening exhaust bolts to the manufacturer's specification.
- Click-type mechanism
- Wide torque range (typically 10-100 ft-lbs)
- Clearly marked scale
Torque Wrench (3/8" drive)
A smaller torque wrench is useful for accessing hard to reach places or for low torque spec fasteners.
- Click-type mechanism
- Smaller torque range (typically 5-50 ft-lbs)
- Clearly marked scale
Socket Set (Metric)
A set of metric sockets, including sizes commonly used on BMW exhaust systems.
- Variety of sizes
- 6-point design for secure grip
- Durable construction (e.g., chrome vanadium steel)
Wrench Set (Metric)
A set of metric wrenches in case socket access is not possible
- Variety of sizes
- Durable construction (e.g., chrome vanadium steel)
- Various types (e.g., combination, open-end)
Universal Joint
A universal joint will allow you to access fasteners from various angles.
- 1/2 or 3/8 inch drive
- Durable construction (e.g., chrome vanadium steel)
Service Procedures
Exhaust Manifold Installation
Procedure for installing or reinstalling the exhaust manifold, including torque specifications.
- Clean the mating surfaces of the exhaust manifold and cylinder head.
- Position the new exhaust manifold gasket.
- Install the exhaust manifold onto the cylinder head.
- Hand-tighten all exhaust manifold bolts.
- Torque the exhaust manifold bolts to 22 Nm (16 ft-lbs) using a torque wrench in a progressive manner (center out).
- Check for leaks and retorque if needed once engine is up to temperature.
Exhaust Downpipe Installation
Procedure for installing or reinstalling the exhaust downpipe, including torque specifications.
- Clean the mating surfaces of the exhaust downpipe and exhaust manifold.
- Position the new gasket.
- Install the downpipe onto the exhaust manifold.
- Hand-tighten all downpipe bolts.
- Torque the downpipe bolts to 25 Nm (18 ft-lbs) using a torque wrench.
- Check for leaks and retorque if needed once engine is up to temperature.
Exhaust System Support Bracket Installation
Procedure for installing or reinstalling the support brackets, including torque specifications.
- Install the exhaust support bracket onto the chassis.
- Hand-tighten all support bracket bolts.
- Torque the support bracket bolts to 21 Nm (15 ft-lbs) using a torque wrench.
- Ensure proper alignment and support before moving to the next step.
Technical Service Bulletins
Exhaust Bolt Loosening Issue
2008-07-15Some 2005-2008 models have experienced exhaust bolt loosening due to thermal expansion and contraction cycles.
Resolution: Apply a small amount of high temperature anti-seize to the threads of exhaust bolts during reinstallation. Verify and re-torque the exhaust hardware after 500-1000 miles of operation.
Exhaust Gasket Leakage
2010-03-20Certain 2009-2011 models may experience exhaust leaks due to poor quality exhaust gaskets. Inconsistent manufacturing tolerances can contribute to premature gasket failure.
Resolution: When replacing exhaust gaskets, only use OEM gaskets or aftermarket gaskets from reputable manufacturers. Ensure proper torque specification is used when reinstalling the hardware.
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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.