BMW 340i 2019-present 3.0L Engine Bolt Torque Specifications & Fastener Values
BMW 340i 2019-present

BMW 340i 2019-present 3.0L Engine Bolt Torque Specifications

Comprehensive guide to the torque specifications for bolts on the 3.0L engine found in the 2019-Present BMW 340i (G20) models. This includes cylinder head, main bearing, connecting rod, and other critical engine bolt torques.

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

Components related to the cylinder head, including securing it to the engine block and related valvetrain components.

1

Cylinder Head Bolts

M12 x 1.5
Important Notes
Tighten in a specific sequence, usually starting from the center and moving outwards. Refer to service manual for specific pattern.
2

Camshaft Bearing Cap Bolts

M8 x 1.25
Important Notes
These bolts require a torque-plus-angle tightening procedure. These are likely stretch bolts and must be replaced if removed.
3

Rocker Arms/Shafts Bolts

M8 x 1.25
Torque Value
20 ft-lbs (27 N·m)
Important Notes
Tighten evenly to ensure proper valve actuation.
4

Variable Valve Timing (VVT) Solenoid Bolts

M6 x 1.0
Torque Value
8 ft-lbs (11 N·m)
Important Notes
Tighten evenly and do not over-tighten the bolts to prevent damage to the solenoids.
5

Vanos Unit Bolts

M8 x 1.25
Important Notes
These bolts require a torque-plus-angle tightening procedure. These are likely stretch bolts and must be replaced if removed.

Engine Block

Components directly related to the engine block, including crankshaft and oil system parts.

1

Main Bearing Bolts

M12 x 1.5
Torque Value
40 ft-lbs (54 N·m)
Important Notes
Tighten in a specific sequence to ensure even pressure on the crankshaft. Check service manual for pattern.
2

Connecting Rod Nuts

M9 x 1.25
Torque Value
20 ft-lbs (27 N·m)
Important Notes
Tighten in a specific sequence to ensure proper and even bearing contact. Check service manual for pattern.
3

Oil Pan Bolts

M6 x 1.0
Torque Value
10 ft-lbs (14 N·m)
Important Notes
Tighten bolts in a criss-cross pattern to ensure even gasket compression. Avoid over tightening.
4

Oil Filter Housing Bolt

M8 x 1.25
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Ensure proper seating and sealing with the gasket.
5

Oil Drain Plug Bolt

M12 x 1.5
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Use a new crush washer for proper sealing.
6

Knock Sensor Bolts

M8 x 1.25
Torque Value
15 ft-lbs (20 N·m)
Important Notes
Ensure sensor is properly seated before tightening. Proper torque is important for accurate sensing.

Intake System

Components related to the intake system, including throttle body and manifold.

1

Intake Manifold Bolts

M6 x 1.0
Torque Value
10 ft-lbs (14 N·m)
Important Notes
Tighten in a criss-cross sequence to prevent leaks. Check manual for pattern.
2

Throttle Body Bolts

M6 x 1.0
Torque Value
10 ft-lbs (14 N·m)
Important Notes
Ensure proper alignment and gasket is correctly installed.
3

Fuel Rail Bolts

M6 x 1.0
Torque Value
10 ft-lbs (14 N·m)
Important Notes
Ensure correct alignment and proper sealing to prevent leaks.
4

Fuel Injector Bolts

M6 x 1.0
Torque Value
10 ft-lbs (14 N·m)
Important Notes
Ensure injectors are fully seated with proper seals. Do not over-tighten.
5

EGR Valve Bolts

M6 x 1.0
Torque Value
10 ft-lbs (14 N·m)
Important Notes
Ensure correct alignment and proper sealing to prevent leaks.

Exhaust System

Components related to the exhaust system, including manifold and headers.

1

Exhaust Manifold/Headers to Cylinder Head Bolts

M8 x 1.25
Torque Value
20 ft-lbs (27 N·m)
Important Notes
Tighten in a specific sequence from the center outwards to ensure a proper seal and prevent leaks. Check service manual for specific pattern.

Cooling System

Components related to the engine's cooling system.

1

Water Pump Bolts

M6 x 1.0
Torque Value
10 ft-lbs (14 N·m)
Important Notes
Ensure the water pump is correctly aligned and the gasket is in good condition. Tighten evenly to prevent leaks.
2

Water Pump Pulley Bolts

M6 x 1.0
Torque Value
10 ft-lbs (14 N·m)
Important Notes
Ensure proper pulley alignment. Do not over-tighten.
3

Thermostat Housing Bolts

M6 x 1.0
Torque Value
10 ft-lbs (14 N·m)
Important Notes
Ensure thermostat and gasket are correctly installed.

Front End Accessory Drive

Components related to the front end accessory drive system, including belt tensioners and pulleys.

1

Serpentine/Accessory Drive Belt Tensioner Bolt

M10 x 1.5
Torque Value
30 ft-lbs (41 N·m)
Important Notes
Ensure the belt tensioner is properly aligned before tightening. Do not over-tighten.
2

Drive Belt Idler Pulley Bolt

M10 x 1.5
Torque Value
30 ft-lbs (41 N·m)
Important Notes
Ensure proper pulley alignment before tightening. Do not over-tighten.
3

Crankshaft Pulley/Harmonic Balancer Bolt

M16 x 1.5
Torque Value
80 ft-lbs (108 N·m)
Important Notes
Ensure the harmonic balancer is properly seated on the crankshaft before tightening. Use a holding tool to keep the crank from turning.

Valve Train

Components related to the valve train including camshaft and timing components.

1

Timing Belt/Chain Tensioner Bolt

M8 x 1.25
Torque Value
20 ft-lbs (27 N·m)
Important Notes
Ensure proper tensioner alignment before tightening. Correct tension is critical for proper engine timing. Check service manual for procedure.
2

Camshaft Sprocket Bolt

M10 x 1.5
Torque Value
60 ft-lbs (81 N·m)
Important Notes
Ensure correct alignment with timing marks and proper camshaft orientation before tightening. Use a cam holding tool if needed.

Ignition System

Components related to the ignition system, including spark plugs and ignition coils.

1

Spark Plugs

M14 x 1.25
Torque Value
20 ft-lbs (27 N·m)
Important Notes
Use a torque wrench with a spark plug socket to achieve correct torque. Do not over-tighten.
2

Ignition Coil Bolts

M6 x 1.0
Torque Value
10 ft-lbs (14 N·m)
Important Notes
Tighten evenly to ensure proper electrical contact. Do not over-tighten.

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?

Torque specifications ensure that fasteners are tightened to the correct clamping force. Over-tightening can damage threads or components, while under-tightening can lead to leaks, loosening, and component failure. For example, incorrect torque on cylinder head bolts can cause head gasket leaks or engine damage.

Q2

What type of tool should I use to tighten bolts?

A torque wrench is essential for accurately tightening bolts to the specified torque. Using a standard wrench without a torque setting can lead to incorrect tightening. For example, using a standard wrench on an oil pan drain plug can easily result in stripping the threads.

Q3

Should I use new bolts when working on the engine?

In many cases, yes. Some bolts, particularly those used for critical components like the cylinder head or connecting rods, are designed to stretch during tightening. These bolts should always be replaced. Reusing these can lead to improper clamping forces and engine failure. Always consult your BMW repair manual for guidance on bolt replacement.

Q4

What does 'Nm' and 'lb-ft' mean?

'Nm' stands for Newton-meters, the metric unit for torque. 'lb-ft' stands for pound-feet, the imperial unit for torque. You will often see torque specs listed in both units. Ensure your torque wrench is set to the correct unit before tightening.

Q5

Do torque specifications change with aftermarket parts?

Yes, they can. If you are using aftermarket components, always refer to the torque specifications provided by the aftermarket manufacturer. Do not assume BMW torque specs will apply, as differences in materials and design can impact the required clamping force. For instance, an aftermarket intake manifold might require different torque settings than the OEM manifold.

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 (1/2" Drive)

A high-quality torque wrench is essential for accurately tightening bolts to the specified torque values.

  • Wide torque range (e.g., 20-200 ft-lbs)
  • Accuracy within +/- 3%
  • Audible click and/or digital display
Learn more

Torque Wrench (3/8" Drive)

A smaller torque wrench for lower torque applications like valve covers and intake components.

  • Lower torque range (e.g., 5-80 ft-lbs)
  • Accuracy within +/- 3%
  • Audible click and/or digital display
Learn more

Socket Set (Metric)

A comprehensive set of metric sockets to fit various bolt and nut sizes on the engine.

  • Various sizes from 8mm to 19mm (and possibly larger)
  • 6-point sockets preferred for better grip
  • Deep and standard sockets
Learn more

Extension Bars (Various Lengths)

Extension bars to access difficult to reach bolts and nuts.

  • Various length from 3" to 12"
  • 3/8" and 1/2" drive options
  • Locking mechanisms
Learn more

Universal Joint

A universal joint to help torque bolts at an angle.

  • 3/8" and 1/2" drive options
  • Swiveling motion
Learn more

Thread Locker (Medium Strength)

Medium-strength thread locker, such as Loctite 243, is used on bolts that require added security against loosening due to vibration.

  • Prevents loosening of bolts
  • Medium strength
  • Removable with hand tools
Learn more

Engine Oil

High quality, correct specification engine oil to lubricate engine components on reassembly.

  • Correct viscosity for engine type
  • High temp rating
Learn more
Service Procedures

Cylinder Head Bolt Torque Procedure

Procedure for properly torquing the cylinder head bolts on the B58 engine.

  • Clean all bolt threads and the bolt holes in the cylinder block.
  • Install new cylinder head bolts.
  • Tighten all bolts in the specified sequence to the first stage torque value (typically 30 Nm)
  • Tighten all bolts in the specified sequence to the second stage torque value (typically an additional 90 degrees)
  • Verify torque values with torque wrench
View full procedure

Connecting Rod Bolt Torque Procedure

Procedure for properly torquing the connecting rod bolts on the B58 engine.

  • Clean all bolt threads and connecting rod bolt holes
  • Install new connecting rod bolts
  • Apply a light coat of engine oil to the bolt threads
  • Tighten bolts to the first stage torque value (typically 20 Nm)
  • Tighten bolts to the second stage torque value (typically an additional 70 degrees)
  • Verify torque values with torque wrench
View full procedure

Oil Pan Bolt Torque Procedure

Procedure for properly torquing the oil pan bolts on the B58 engine.

  • Clean all bolt threads and oil pan bolt holes
  • Install oil pan and bolts
  • Tighten bolts to the specified torque value (typically 10 Nm)
  • Tighten bolts in a crisscross pattern.
  • Verify torque values with torque wrench
View full procedure

Valve Cover Bolt Torque Procedure

Procedure for properly torquing the valve cover bolts on the B58 engine.

  • Clean all bolt threads and valve cover bolt holes
  • Install valve cover and bolts
  • Tighten bolts to the specified torque value (typically 10 Nm)
  • Tighten bolts in a crisscross pattern.
  • Verify torque values with torque wrench
View full procedure
Technical Service Bulletins

BMW Technical Service Bulletin: B58 Engine Cylinder Head Bolt Issues

2020-05-15

Some early B58 engines may exhibit cylinder head bolt stretch due to improper tightening. This can result in cylinder head gasket failure and coolant leaks.

2019-2020 340i

Resolution: Ensure all cylinder head bolts are replaced and torqued according to the latest BMW service guidelines. Use a new set of bolts, torque to the correct spec, and replace the cylinder head gasket

BMW Technical Service Bulletin: B58 Oil Leakage from Oil Pan

2021-02-20

Some B58 engines may exhibit oil leakage due to improper oil pan bolt torque or gasket degradation.

2019-2021 340i

Resolution: Replace the oil pan gasket and verify the oil pan bolts are tightened to the correct torque specification. Clean the surface and reinstall with new gasket.

About the Author

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Alan Montanye - Automotive Technical Specialist
ASE

Alan Montanye

Automotive Technical Specialist

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