BMW 640i 2011-2018 Emissions & Sensor Bolt Torque Specifications
BMW 640i 2011-2018

BMW 640i 2011-2018 Emissions & Sensor Bolt Torque Specifications

This page provides detailed torque specifications for bolts related to emissions sensors on the 2011-2018 BMW 640i (F12, F13, F06 generation). Includes values for various sensor mounting points and related components.

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

Exhaust System

Torque specifications for components within the exhaust system that directly impact emissions and sensor readings.

1

Exhaust Gas Recirculation (EGR) Valve Bolts

M8 x 1.25
Torque Value
10 ft-lbs (14 N·m)
Important Notes
Ensure proper alignment of the EGR valve before tightening bolts to avoid leaks.
2

Exhaust Manifold/Headers Bolts

M10 x 1.5
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Tighten bolts in a specified sequence starting from the center bolts moving outwards. Refer to the service manual for the specific sequence.
3

Exhaust Pipe to Exhaust Manifold/Headers Bolts

M10 x 1.5
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Use new gaskets when installing to avoid exhaust leaks.
4

Catalytic Converter to Exhaust Pipe Bolts

M10 x 1.5
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Ensure a proper seal to maintain catalytic converter efficiency. Use new gaskets.
5

Oxygen Sensor

M18 x 1.5
Torque Value
33 ft-lbs (45 N·m)
Important Notes
Apply anti-seize compound to the sensor threads. Estimated value based on typical O2 sensor size.
6

Nitrogen Oxide (NOx) Sensor Bolts/Screws

M6 x 1.0
Torque Value
6 ft-lbs (8 N·m)
Important Notes
Estimated value based on typical small sensor mounting bolt size. Confirm with OEM specifications.

Intake System

Torque specifications for components within the intake system that affect air metering and temperature measurements.

1

Mass Air Flow (MAF) Sensor Bolts

M5 x 0.8
Torque Value
6 ft-lbs (8 N·m)
Important Notes
Be careful not to over-tighten these bolts as the MAF housing is usually plastic. Estimated based on typical sensor mount size.
2

Intake Air Temperature (IAT) Sensor Bolts/Screw

M4 x 0.7
Torque Value
4 ft-lbs (5.5 N·m)
Important Notes
Typically plastic housing; low torque is needed. Estimated based on typical sensor mount size.
3

Manifold Absolute Pressure (MAP) Sensor Bolts/Screws

M5 x 0.8
Torque Value
6 ft-lbs (8 N·m)
Important Notes
Estimated value. Use caution when tightening on plastic components.

Fuel System

Torque specifications for components within the fuel system that impact emissions and fuel metering.

1

Fuel Injector Bolts

M6 x 1.0
Torque Value
7 ft-lbs (9 N·m)
Important Notes
Be careful not to over tighten. Ensure proper injector sealing.
2

Fuel Rail Bolts

M8 x 1.25
Torque Value
10 ft-lbs (14 N·m)
Important Notes
Ensure the fuel rail is properly seated and sealed before tightening. May need to be tightened evenly in multiple passes.

Evaporative Emissions System

Torque specifications for components related to the evaporative emissions control system.

1

Evaporative Emissions (EVAP) Canister Mounting Bolts

M8 x 1.25
Torque Value
10 ft-lbs (14 N·m)
Important Notes
Estimated value; ensure secure mounting to avoid leaks. May be a combination of bolts and screws, which should all follow the same torque value.
2

EVAP Purge Valve Bolts/Screws

M5 x 0.8
Torque Value
6 ft-lbs (8 N·m)
Important Notes
Usually plastic housing; low torque to prevent damage. Estimated value based on typical EVAP purge valve size.

Positive Crankcase Ventilation System

Torque specifications for the PCV valve mounting.

1

Crankcase Ventilation Valve (PCV Valve) bolts/screws

M5 x 0.8
Torque Value
7 ft-lbs (9.5 N·m)
Important Notes
Be careful not to over-tighten small bolts. Estimated value.

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 is using the correct torque specification important for emissions sensors?

Correct torque is crucial for emissions sensors to ensure a proper seal, prevent leaks, and obtain accurate readings. Over-tightening can damage the sensor or threads, while under-tightening can lead to exhaust leaks, inaccurate data, and potential check engine lights. These readings are vital for your BMW's emissions control system and overall engine health.

Q2

What happens if I over-tighten an emissions sensor bolt?

Over-tightening an emissions sensor bolt can cause several issues. It can strip the threads in the exhaust manifold or mounting point, potentially leading to costly repairs. It can also damage the sensor itself, causing it to become inaccurate or fail completely. Additionally, over-tightening can lead to sensor housing damage which may lead to leaks and a check engine light.

Q3

What if I under-tighten an emissions sensor bolt?

Under-tightening an emissions sensor bolt will not provide a proper seal. This can lead to exhaust leaks, especially with the high temperatures and pressures. Leaks can affect sensor readings, trigger a check engine light, and may lead to inaccurate engine management. For example, an improperly sealed O2 sensor could cause your engine to run lean or rich.

Q4

Should I use new gaskets or seals when replacing emissions sensors?

Yes, it is highly recommended to use new gaskets or seals whenever you replace an emissions sensor. Old gaskets or seals can become compressed or damaged over time, making it difficult to achieve a proper seal. Reusing them increases the risk of leaks and subsequent problems. For example, a new O2 sensor may not seal properly if installed with an old crush washer.

Q5

Can I use thread sealant on emissions sensor bolts?

Generally, it's not recommended to use thread sealant on emissions sensor bolts unless specifically stated by BMW. Using the correct torque is generally sufficient, and thread sealant can interfere with proper electrical grounding on some sensor designs. Always consult your service manual or a trusted mechanic if you think it is necessary. It's best to keep the threads clean.

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 (1/4" Drive)

A precision tool for applying specific torque values to fasteners. A 1/4" drive is suitable for the smaller fasteners used on emissions sensors.

  • Click-type mechanism for accurate torque application
  • Adjustable torque range covering specified values
  • Easy to read scale
Learn more

Socket Set (1/4" Drive, Metric)

A set of metric sockets to fit the various fastener heads on the emissions sensors. Sizes typically needed include 8mm, 10mm, and 13mm

  • Standard socket sizes for various applications
  • Durable construction
  • Includes a ratchet handle
Learn more

Extension Bars (1/4" Drive)

Extension bars are needed to reach recessed or difficult-to-access fasteners on the emissions system.

  • Multiple length sizes for better access
  • Durable construction
  • Secure locking mechanism
Learn more

Torx Socket Set (1/4" Drive)

A set of Torx sockets to fit some of the emissions sensor fasteners. Sizes typically needed include T20 and T25.

  • Includes sizes common on BMW vehicles
  • Durable construction
  • Precise fit to prevent stripping
Learn more
Service Procedures

NOx Sensor Removal and Installation

Procedure for safely removing and installing a NOx sensor, ensuring proper torque to avoid damage.

  • Disconnect the negative battery terminal.
  • Locate the NOx sensor on the exhaust system. (Usually near the catalytic converter).
  • Disconnect the electrical connector from the NOx sensor.
  • Using the appropriate socket (8mm or 10mm or torx), loosen and remove the sensor's mounting bolts.
  • Carefully remove the sensor.
  • Install the new NOx sensor, and hand-tighten the mounting bolts.
  • Using the torque wrench, tighten the bolts to the specified torque value (typically around 8-10 Nm).
  • Reconnect the electrical connector to the NOx sensor.
  • Reconnect the negative battery terminal.
  • Clear any stored fault codes.
View full procedure

Oxygen (O2) Sensor Removal and Installation

Procedure for safely removing and installing an O2 sensor, ensuring proper torque to avoid exhaust leaks or sensor damage.

  • Disconnect the negative battery terminal.
  • Locate the oxygen sensor on the exhaust system, upstream or downstream of the catalytic converter.
  • Disconnect the electrical connector from the O2 sensor.
  • Using the appropriate socket (typically 22mm or special O2 sensor socket), loosen and remove the sensor.
  • Apply anti-seize to the threads of the new O2 sensor.
  • Install the new O2 sensor, and hand-tighten.
  • Using the torque wrench, tighten the sensor to the specified torque value (typically around 30-45 Nm).
  • Reconnect the electrical connector to the O2 sensor.
  • Reconnect the negative battery terminal.
  • Clear any stored fault codes.
View full procedure

Exhaust Gas Temperature (EGT) Sensor Removal and Installation

Procedure for safely removing and installing an EGT sensor, ensuring proper torque to avoid exhaust leaks or sensor damage.

  • Disconnect the negative battery terminal.
  • Locate the exhaust gas temperature sensor on the exhaust system, typically near the catalytic converter or DPF.
  • Disconnect the electrical connector from the EGT sensor.
  • Using the appropriate socket (usually 8mm or 10mm or torx), loosen and remove the sensor's mounting bolts.
  • Carefully remove the sensor.
  • Install the new EGT sensor, and hand-tighten the mounting bolts.
  • Using the torque wrench, tighten the bolts to the specified torque value (typically around 8-10 Nm).
  • Reconnect the electrical connector to the EGT sensor.
  • Reconnect the negative battery terminal.
  • Clear any stored fault codes.
View full procedure
Technical Service Bulletins

Reduced Engine Performance Due to NOx Sensor Fault

2017-05-15

Some 2012-2016 BMW 640i models may experience reduced engine performance and the engine malfunction lamp (MIL) may illuminate due to a faulty NOx sensor. Diagnostic trouble codes may include P2201, P2202, P2203, or similar codes related to NOx sensor performance.

2012-2016 BMW 640i

Resolution: Inspect and, if necessary, replace the NOx sensor. Ensure correct torque is applied to mounting bolts during re-installation, as specified by BMW. Also check the wiring harness and connectors for any damage.

O2 Sensor Heater Circuit Fault

2014-11-20

Certain 2011-2014 BMW 640i vehicles may exhibit O2 sensor heater circuit malfunctions. Symptoms can include delayed engine starting and poor fuel economy. Diagnostic trouble codes like P0030, P0031, or P0032 may be logged.

2011-2014 BMW 640i

Resolution: Inspect the O2 sensor heater circuit, including the sensor itself, wiring, and connectors. Verify proper sensor grounding. Replace the faulty sensor if necessary, applying appropriate torque during installation. Clear fault codes after repair.

EGT Sensor Reading High, Affecting DPF Performance

2019-02-28

Some 2016-2018 BMW 640i vehicles may display high exhaust gas temperature (EGT) sensor readings, potentially affecting Diesel Particulate Filter (DPF) performance and causing the engine to go into limp mode. Relevant codes may include P2031, P2032, or P2033.

2016-2018 BMW 640i

Resolution: Check the EGT sensor, wiring harness, and connectors for damage. Inspect for possible blockages near the sensor. Replace the sensor as needed, ensuring correct torque during installation to prevent leaks.

About the Author

Expert automotive knowledge and experience

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.

Facebook Contact
15+ Years
Experience
500+ Guides
Guides
50+ Makes
Vehicles
1000+ Solutions
Solutions

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
The information provided on this website is for general informational purposes only. While we strive to maintain accuracy in our content, all specifications, procedures, and technical information should be verified against your vehicle's official service manual or with the manufacturer directly.
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.
Intellectual Property
All content, including text, images, and specifications, is protected by copyright and other intellectual property laws. Any unauthorized use or reproduction is prohibited.

© 2025 BMW Specs. All rights reserved.

Privacy Policy Terms of Service