BMW 340i 2012-2018 3.0L Engine Bolt Torque Specifications & Fastener Values
BMW 340i 2012-2018

BMW 340i 2012-2018 3.0L Engine Bolt Torque Specifications

Comprehensive list of torque specifications for the 3.0 liter engine bolts in the 2012-2018 BMW 340i (F30) model, including cylinder head, main bearings, and more.

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

Cylinder Head

Specifications for bolts and fasteners related to the cylinder head, ensuring proper sealing and compression.

1

Cylinder Head Bolts

M12 x 1.75
Important Notes
Torque in sequence, refer to specific service manual for pattern. Final steps are angle torques. Be sure to use new bolts and lubricate threads before installation.

Crankshaft

Specifications for components related to the crankshaft, such as main bearing caps and the flywheel, critical for engine rotation and balance.

1

Main Bearing Bolts

M10 x 1.5
Important Notes
Torque in proper sequence. Angle torque is critical for proper clamping force.
2

Flywheel Bolts

M12 x 1.5
Torque Value
55 ft-lbs (75 N·m)
Important Notes
Torque in a star pattern. Ensure flywheel is properly seated against the crankshaft flange.
3

Crankshaft Pulley/Harmonic Balancer Bolt

M18 x 1.5
Torque Value
170 ft-lbs (230 N·m)
Important Notes
Use a holding tool to prevent crankshaft rotation. This is a critical and high torque bolt.

Connecting Rods

Specifications for the connecting rod bolts, which are vital for piston movement and must be torqued accurately.

1

Connecting Rod Nuts

M9 x 1.25
Important Notes
Torque in sequence. Angle torque is critical for proper clamping force.

Oil System

Specifications for components related to the oil system, including the oil pan, filter, and drain plug, which are critical for maintaining oil pressure and preventing leaks.

1

Oil Pan Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Torque in a crisscross pattern to ensure even sealing. Do not over-tighten. Note: 7 ft-lbs is equal to 84 inch-lbs, so 89 in-lbs is a close estimate.
2

Oil Filter Cap

N/A
Torque Value
17 ft-lbs (23 N·m)
Important Notes
Hand-tight plus a slight snug. Be careful not to over-tighten. Estimated Value.
3

Oil Filter Housing Bolts

M8 x 1.25
Torque Value
12 ft-lbs (16 N·m)
Important Notes
Hand-tight plus a slight snug. Be careful not to over-tighten. Estimated Value.
4

Oil Drain Plug Bolt

M12 x 1.5
Torque Value
30 ft-lbs (40 N·m)
Important Notes
Use a new crush washer. Do not over-tighten.

Valvetrain

Specifications for components related to the valvetrain, ensuring proper valve timing and sealing.

1

Valve Cover Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Torque in a crisscross pattern. Do not over-tighten.
2

Timing Belt/Chain Tensioner Bolt

M8 x 1.25
Torque Value
15 ft-lbs (20 N·m)
Important Notes
Ensure proper timing and tension on the belt/chain.
3

Camshaft Sprocket Bolts

M10 x 1.5
Torque Value
63 ft-lbs (85 N·m)
Important Notes
Use a camshaft holding tool to prevent rotation.
4

Rocker Arms/Shafts Bolts

M8 x 1.25
Torque Value
19 ft-lbs (26 N·m)
Important Notes
Torque in sequence. Refer to manual for proper sequence.
5

VANOS Solenoid Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Do not over-tighten, as this can damage the solenoid.

Ignition System

Specifications for components related to the ignition system, ensuring proper spark plug function and coil operation.

1

Spark Plugs

M14 x 1.25
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Use a torque wrench to avoid over-tightening. Use proper anti-seize.
2

Ignition Coil Bolt

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Do not over-tighten.

Intake System

Specifications for components related to the intake system, ensuring proper airflow and preventing vacuum leaks.

1

Throttle Body Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Torque in a crisscross pattern to ensure even sealing.
2

Intake Manifold Bolts

M8 x 1.25
Torque Value
14 ft-lbs (19 N·m)
Important Notes
Torque in a proper sequence; refer to the service manual. Check for leaks after install.
3

Fuel Injector Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Ensure fuel injectors are seated correctly before tightening.
4

Fuel Injector Rail Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Ensure fuel rail is properly positioned before tightening.

Exhaust System

Specifications for components related to the exhaust system, ensuring proper sealing and preventing leaks.

1

Exhaust Manifold/Headers Bolts

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Torque in sequence, check for leaks after install.

Cooling System

Specifications for components related to the cooling system, ensuring proper coolant circulation and preventing leaks.

1

Water Pump Bolts

M8 x 1.25
Torque Value
15 ft-lbs (20 N·m)
Important Notes
Torque in a crisscross pattern to ensure even sealing.
2

Water Pump Pulley Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Do not over-tighten. Ensure the pulley is seated flat.
3

Thermostat Housing Bolts

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Torque in a crisscross pattern to ensure even sealing.

Sensors

Specifications for sensor mounting bolts, critical for accurate engine monitoring.

1

Knock Sensor Bolts

M8 x 1.25
Torque Value
15 ft-lbs (20 N·m)
Important Notes
Do not over-tighten, which could damage the sensor.
2

Crank Position Sensor Bolt

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Do not over-tighten; proper alignment is important.

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 are torque specifications important?

Using the correct torque specifications ensures that bolts are tightened enough to provide a secure connection, preventing leaks, component failures, and vibrations. Over-tightening can strip threads or damage parts, while under-tightening can cause components to loosen during operation, leading to potentially catastrophic failure. Correct torque is crucial for the longevity and performance of your BMW 340i's engine.

Q2

What is the difference between Nm and lb-ft?

Nm (Newton-meters) and lb-ft (pound-feet) are both units of torque. Nm is the metric unit commonly used in Europe and is the default measurement for BMW. lb-ft is an imperial unit used primarily in the United States. Torque wrenches often display both. 1 Nm is approximately equal to 0.73756 lb-ft. Always double-check which unit is being used by your torque wrench before tightening.

Q3

What type of lubricant should I use on bolts?

Generally, use engine oil for bolts going into the aluminum block or head, and anti-seize on bolts exposed to harsh conditions such as exhaust manifold bolts. Avoid excessive lubrication, and always refer to the specific repair manual as some bolts are designed for dry installation. Ensure that the torque specification provided is correct for the condition of the bolt being lubricated or not.

Q4

How often should I check the torque on critical engine bolts?

It's generally a good practice to re-torque critical engine bolts such as the cylinder head bolts or main bearing caps after a few heat cycles, such as after starting and driving a mile and then allowing to cool before checking the bolts. Refer to BMW-specific documentation for recommended intervals and procedures. For typical component replacements, a one-time torque to the required spec is usually sufficient.

Q5

What is torque-to-yield and how is it used with engine components?

Torque-to-yield (TTY) bolts are designed to stretch when tightened to the correct torque value. They are only good for one time use and MUST be replaced if removed. These bolts generally have torque specifications in two steps; a first torque value followed by a specific angle tightening procedure (ex: 30 Nm + 90 degrees). Failure to follow the correct procedure can lead to damage. Always follow the torque specifications exactly.

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

A calibrated torque wrench is essential for accurate bolt tightening.

  • Ability to measure torque in Newton-meters (Nm)
  • Adjustable torque settings
  • Click-type or digital display
Learn more

Socket Set (Metric)

A comprehensive set of metric sockets is required to fit various bolt heads.

  • Various sizes from 8mm to 19mm
  • 6-point sockets for secure grip
  • Shallow and deep well socket options
Learn more

Extension Bars

Extension bars are needed to reach bolts in recessed areas.

  • Various lengths for different reach requirements
  • 3/8" or 1/2" drive compatibility
  • Locking mechanisms to prevent slippage
Learn more

Universal Joint

A universal joint allows for torque application at an angle.

  • Flexible swivel design
  • 3/8" or 1/2" drive compatibility
  • Durable construction
Learn more

Torque Angle Meter (Optional)

A torque angle meter is used to achieve specific angles of rotation after torqueing.

  • Digital or analog angle display
  • Secure attachment to torque wrench
  • Precise angle measurement
Learn more
Service Procedures

Cylinder Head Bolt Tightening Procedure (B58 Engine)

This procedure outlines the correct sequence and torque specifications for cylinder head bolts.

  • Ensure all bolts are lightly lubricated with engine oil.
  • Follow the specific tightening sequence as per BMW's repair manual.
  • Tighten all bolts to the first stage torque specification (e.g., 20 Nm).
  • Tighten all bolts to the second stage torque specification (e.g., 70 Nm).
  • Perform the final stage using angle tightening (e.g., +90 degrees, then +90 degrees).
View full procedure

Oil Pan Bolt Tightening Procedure (B58 Engine)

This procedure details the correct method for tightening oil pan bolts.

  • Ensure the oil pan gasket is correctly seated.
  • Begin tightening bolts by hand to avoid cross-threading
  • Tighten the bolts in a criss-cross pattern to the specified torque (e.g., 10 Nm).
  • Verify all bolts are tightened evenly and securely.
View full procedure

Intake Manifold Bolt Tightening Procedure (B58 Engine)

This procedure outlines the tightening process for intake manifold bolts.

  • Start all bolts by hand to avoid cross threading.
  • Tighten the intake manifold bolts in a specified sequence (inner to outer) using the torque wrench.
  • Tighten all bolts to the specified torque specification (e.g., 18 Nm).
  • Verify the manifold is securely mounted to the engine.
View full procedure

Valve Cover Bolt Tightening Procedure (B58 Engine)

This procedure details the correct method for tightening valve cover bolts.

  • Ensure the valve cover gasket is correctly seated.
  • Tighten the valve cover bolts using a star pattern to the specified torque (e.g., 10 Nm).
  • Avoid over-tightening to prevent damage to the cover or gasket.
  • Verify a proper seal is achieved.
View full procedure
Technical Service Bulletins

Excessive Oil Consumption on B58 Engines

2017-05-15

This bulletin addresses reported cases of excessive oil consumption in early production B58 engines, primarily due to piston ring issues.

2016-2017 BMW 340i 2016-2017 BMW 440i 2016-2017 BMW 740i

Resolution: Inspect piston rings and replace if necessary, following the updated repair procedures, including torque specifications.

Coolant Leakage from Cylinder Head Area

2018-02-28

This bulletin addresses instances of coolant leakage in the cylinder head area, sometimes linked to improper torque application during prior service.

2016-2018 BMW 340i 2016-2018 BMW 440i

Resolution: Inspect the cylinder head gasket and bolts, ensure proper torque sequence and tightening specifications are followed, replace if needed.

About the Author

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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.

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