BMW Vehicle Models 640i 2018-present Torque Specifications
BMW Vehicle Models 640i 2018-present

BMW Vehicle Models 640i 2018-present Torque Specifications

Complete BMW Vehicle Models 640i 2018-present torque specifications guide. Includes factory-specified torque values, torque sequences, and technical specifications for all components including body, brakes, drivetrain, electrical, emissions sensors, fuel, exhaust, HVAC, and suspension. Essential information for proper assembly and maintenance.

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

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Torque Calculator

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3.0l Engine

Torque specifications for 3.0L Engine

Cylinder Head

1

Cylinder Head Bolts

M12 x 1.5
Torque Specification
1. 18 ft-lbs (24 N·m) 2. 90° 3. 90°
Important Notes
Follow specific torque sequence. Use new bolts. Angle tightening is required, please refer to a specific service manual for the correct sequence.
2

Exhaust Manifold/Headers to Cylinder Head Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Tighten evenly to ensure proper sealing and prevent exhaust leaks.

Crankshaft And Rotating Assembly

1

Main Bearing Bolts

M10 x 1.5
Torque Specification
1. 45 ft-lbs (61 N·m) 2. 70°
Important Notes
Follow specific torque sequence. Use new bolts. Angle tightening is required, please refer to a specific service manual for the correct sequence.
2

Connecting Rod Nuts

M8 x 1.25
Torque Specification
1. 20 ft-lbs (27 N·m) 2. 70°
Important Notes
Follow correct torque sequence. Use new nuts. Angle tightening is required, please refer to a specific service manual for the correct sequence.
3

Flywheel Bolts

M12 x 1.5
Torque Specification
50 ft-lbs (68 N·m)
Important Notes
Tighten bolts evenly to ensure proper flywheel attachment.
4

Crankshaft Pulley/Harmonic Balancer Bolt

M14 x 1.5
Torque Specification
90 ft-lbs (122 N·m)
Important Notes
Ensure pulley is properly seated. A special tool may be needed to hold the crankshaft while tightening.

Engine Lubrication

1

Oil Pan Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Use a new gasket and tighten bolts in a cross pattern to ensure even seal. Avoid over-tightening.
2

Oil Filter Housing Bolt

M8 x 1.25
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Ensure new o-ring/seal is used. Tighten evenly to prevent leaks.
3

Oil Drain Plug Bolt

M14 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a new crush washer/seal for a proper seal. Avoid over-tightening, which could damage the pan.
4

Oil Cooler Mounting Bolts

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Tighten evenly to prevent leaks. Ensure proper gasket or seals are in place.
5

Oil Cooler Lines to Engine Block Bolts

M8 x 1.25
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
Tighten evenly to prevent leaks. Check for leaks after installation.
6

Oil Pressure Sensor

M10 x 1.0
Torque Specification
12 ft-lbs (16 N·m)
Important Notes
Tighten the sensor to prevent leaks, do not overtighten.

Valve Train

1

Valve Cover Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Tighten in a cross pattern to ensure even pressure and a proper seal. Avoid overtightening.
2

Camshaft Sprocket Bolt

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Tighten to ensure proper timing. Ensure the camshaft is locked in place before torquing.
3

Camshaft Bearing Cap Bolts

M6 x 1.0
Torque Specification
1. 10 ft-lbs (14 N·m) 2. 45°
Important Notes
Tighten in sequence to evenly distribute pressure. Angle tightening is required, please refer to a specific service manual for the correct sequence.
4

Rocker Arms/Shafts Bolts

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Ensure proper alignment of the rocker arms/shafts. Tighten evenly.
5

Timing Belt/Chain Tensioner Bolt

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Proper tension must be applied to the timing belt/chain before tightening the bolt to ensure correct timing.
6

VANOS Solenoid Bolts

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Do not over tighten these, ensure proper o-ring or seal placement.

Intake And Exhaust

1

Throttle Body Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Tighten evenly to ensure proper sealing. Avoid overtightening.
2

Intake Manifold Bolts

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Tighten in a cross pattern to ensure even pressure and a proper seal. Do not over-tighten these.
3

Intake Manifold Runner Control Actuator Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Tighten evenly to ensure proper sealing. Avoid overtightening.
4

EGR Valve Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Tighten evenly to ensure proper sealing. Avoid overtightening.

Fuel System

1

Fuel Rail Bolts

M6 x 1.0
Torque Specification
9 ft-lbs (12 N·m)
Important Notes
Tighten evenly to avoid fuel leaks. Avoid over-tightening.
2

Fuel Injector Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Tighten evenly to ensure proper sealing. Avoid overtightening.

Cooling System

1

Water Pump Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Tighten evenly in a cross pattern to ensure proper sealing and avoid leaks.
2

Water Pump Pulley Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Tighten evenly to prevent vibration and ensure proper belt drive.
3

Thermostat Housing Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Tighten evenly to avoid coolant leaks. Use a new gasket/seal.
4

Coolant Temperature Sensor

M10 x 1.0
Torque Specification
12 ft-lbs (16 N·m)
Important Notes
Tighten the sensor to prevent leaks, do not overtighten.

Engine Sensors And Electrical

1

Knock Sensor Bolt

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Tighten to ensure proper sensor readings.
2

Crankshaft Position Sensor Bolt

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Tighten sensor for accurate readings, do not over tighten.
3

Alternator Mounting Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Tighten to ensure correct alternator alignment, avoid over-tightening.
4

Power Steering Pump Mounting Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Tighten to ensure correct power steering pump alignment, avoid over-tightening.

Accessory Drive System

1

Serpentine/Accessory Drive Belt Tensioner Bolt

M10 x 1.5
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Tighten to ensure correct belt tension.
2

Drive Belt Idler Pulley Bolt

M10 x 1.5
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
Tighten to ensure correct idler pulley operation.

Spark Plugs

1

Spark Plugs Torque

M14 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Ensure threads are clean. Use a spark plug socket to tighten. Do not over-tighten or cross thread.

8hp Transmission

Torque specifications for 8hp Transmission

Transmission Mounting

1

Transmission Mounting Bolts

M12 x 1.5
Torque Specification
40 ft-lbs (54 N·m)
Important Notes
Ensure the bolts are properly engaged before tightening. Torque in a cross pattern.

Oil Pan

1

Transmission Oil Pan Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Torque in a cross pattern to ensure even pressure on the gasket or sealant. Over-tightening can warp the pan and cause leaks.

Drain Fill Plugs

1

Transmission Drain and Fill Plugs

M18 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a new sealing washer if required. Do not over-tighten, as this could damage threads or the seal.

Mechatronics Unit

1

Mechatronics Unit Bolts

M5 x 0.8
Torque Specification
7.4 ft-lbs (10 N·m)
Important Notes
Torque in a cross pattern. These bolts are low torque and require careful tightening.

Valve Body

1

Valve Body Bolts

M6 x 1.0
Torque Specification
5.9 ft-lbs (8 N·m)
Important Notes
Torque in a cross pattern to ensure even pressure. Over-tightening could lead to valve body deformation.

Bellhousing

1

Transmission Bellhousing Bolts

M12 x 1.75
Torque Specification
35 ft-lbs (47 N·m)
Important Notes
Ensure the bellhousing is properly aligned before tightening the bolts. Torque to specification.

Torque Converter

1

Torque Converter Bolts

M10 x 1.25
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Bolts should be tightened in a star pattern. Ensure proper orientation of the torque converter.

Output Shaft

1

Output Shaft Flange Nut

M24 x 1.5
Torque Specification
118 ft-lbs (160 N·m)
Important Notes
Ensure the nut is properly engaged. Use a new nut if specified by manufacturer. High torque value - must be accurate.

Cooler Line Fittings

1

Transmission Cooler Line Fittings

M16 x 1.5
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
Ensure the fittings are aligned properly to avoid cross-threading. Over-tightening can damage threads or lines.

Body

Torque specifications for Body

Fuel System

1

Fuel Tank Strap Bolts

M10 x 1.5
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
These bolts secure the fuel tank straps to the vehicle's underbody. Ensure straps are properly aligned before tightening.
2

Fuel Filler Neck Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
These bolts attach the fuel filler neck to the quarter panel or body. Over-tightening can damage the filler neck.

Door System

1

Door Hinge Bolts (to body)

M8 x 1.25
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
These bolts attach the door hinges to the body frame. Ensure proper door alignment before final tightening.
2

Door Latch Striker Bolts (to body)

M8 x 1.25
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
These bolts secure the door latch striker to the body pillar. Check door latch engagement after tightening.
3

Side Mirror Mounting Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
These bolts secure the side mirrors to the door frame. Do not over-tighten, as this may cause damage to mirror assembly or door panel.

Hood Trunk System

1

Hood Hinge Bolts (to hood and body)

M8 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
These bolts attach the hood hinges to both the hood and the body. Ensure smooth hood operation and proper alignment before final tightening.
2

Trunk/Tailgate Hinge Bolts (to body)

M8 x 1.25
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
These bolts attach the trunk lid or tailgate hinges to the body. Proper alignment is essential for correct function.

Exterior Panels

1

Fender Bolts (to body)

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
These bolts attach the fender to the main body frame. Ensure panel gaps are consistent before final tightening.
2

Bumper Mounting Bolts (front and rear)

M10 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
These bolts attach the bumpers to the vehicle's body. Torque value is an estimate, and may vary by specific bolt location.
3

Grille Mounting Bolts

M5 x 0.8
Torque Specification
5 ft-lbs (7 N·m)
Important Notes
These bolts secure the grille to the front fascia/bumper. Do not over-tighten to avoid damage to the grille or mounting points.

Lighting System

1

Headlight Assembly Mounting Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
These bolts secure the headlight assemblies to the body. Be careful not to over-tighten the bolts.
2

Taillight Assembly Mounting Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
These bolts secure the taillight assemblies to the body. Ensure proper fit and alignment before final tightening.

Interior Components

1

Seat Mounting Bolts (to Floor Pan)

M10 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
These bolts secure the seats to the vehicle's floor pan. Proper torque is critical for occupant safety. Ensure all bolts are installed.
2

Interior Trim Panel Bolts/Screws

M4 x 0.7
Torque Specification
3 ft-lbs (4 N·m)
Important Notes
These bolts/screws secure various interior trim panels. Be careful not to over-tighten to avoid damage to the plastic.

Wheels

1

Wheel Lug Nuts

M14 x 1.25
Torque Specification
100 ft-lbs (136 N·m)
Important Notes
Tighten lug nuts in a star pattern to ensure even pressure. Confirm torque specification is correct for your model.

Brakes

Torque specifications for Brakes

Brake Calipers

1

Brake Caliper Mounting Bolts

M12 x 1.5
Torque Specification
75 ft-lbs (102 N·m)
Important Notes
These bolts secure the caliper to the mounting bracket. Ensure proper torque to maintain braking performance.
2

Brake Pad Guide Pin Bolts

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
These bolts secure the guide pins. Ensure they are not over-tightened to allow for free pad movement.
3

Brake Caliper Slide Pin Bolts

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
These bolts secure the caliper slide pins. Ensure proper torque to allow for free caliper movement.

Caliper Brackets

1

Brake Caliper Mounting Bracket Bolts

M14 x 1.5
Torque Specification
100 ft-lbs (136 N·m)
Important Notes
These bolts secure the bracket to the steering knuckle/axle carrier. Follow torque sequence to ensure proper alignment and stability.

Brake Discs

1

Brake Disc/Drum Retaining Bolts

M6 x 1.0
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
These bolts hold the rotor to the hub during assembly. Do not over-tighten.

Wheel Mounting

1

Wheel Lug Nuts

M14 x 1.25
Torque Specification
100 ft-lbs (136 N·m)
Important Notes
These nuts secure the wheel to the hub. Use a star pattern to tighten them evenly for proper seating and to avoid brake rotor distortion.

Brake Hydraulics

1

Brake Bleeder Screw

M7 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
This screw is used to bleed air from the brake system. Do not over-tighten, as it may cause damage or leaks.
2

Brake Line Fitting (Banjo Bolt)

M10 x 1.0
Torque Specification
12 ft-lbs (16 N·m)
Important Notes
This fitting connects the brake line to the caliper. Proper torque is essential to prevent leaks. Estimated value, refer to specific service manual for your vehicle.
3

Brake Line Fitting (Flare Nut)

M10 x 1.0
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
This fitting connects the brake line to other brake lines. Proper torque is essential to prevent leaks. Estimated value, refer to specific service manual for your vehicle.

Electronic Parking Brake

1

Electronic Parking Brake Actuator Bolts

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
These bolts secure the EPB actuator. Ensure proper torque for correct operation. Estimated value, refer to specific service manual for your vehicle.

Drivetrain

Torque specifications for Drivetrain

Engine To Transmission

1

Flywheel Bolts

M10 x 1.25
Torque Specification
1. 25 ft-lbs (34 N·m) 2. 50 ft-lbs (68 N·m)
Important Notes
Tighten bolts in a star pattern in two stages to ensure even clamping force. Final torque is crucial for preventing flywheel slippage and vibrations.
2

Transmission Mounting Bolts

M12 x 1.75
Torque Specification
40 ft-lbs (54 N·m)
Important Notes
Ensure the transmission is properly aligned before tightening the mounting bolts. Proper torque is critical for transmission alignment and preventing vibrations.

Transmission

1

Transmission Oil Pan Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Tighten in a criss-cross pattern to ensure even sealing. Overtightening can damage the pan or gasket.
2

Transmission Drain and Fill Plugs

M18 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a new sealing washer or o-ring on each plug. Do not overtighten to prevent damage to the transmission case.
3

Output Shaft Flange Bolts

M10 x 1.25
Torque Specification
50 ft-lbs (68 N·m)
Important Notes
These bolts connect the output shaft flange to the transmission. Proper torque is critical for reliable power transfer. Estimated value.

Driveshaft

1

Flex Disc Bolts (Guibo)

M12 x 1.5
Torque Specification
1. 25 ft-lbs (34 N·m) 2. 50 ft-lbs (68 N·m)
Important Notes
Tighten in a star pattern in two stages to ensure even clamping force and proper alignment. Estimated value. Use new bolts.
2

Propeller/Drive Shaft Bolts

M10 x 1.25
Torque Specification
45 ft-lbs (61 N·m)
Important Notes
Ensure the driveshaft is properly centered before tightening. Proper torque is essential for preventing vibrations at high speeds.

Differential

1

Differential Mounting Bolts

M14 x 2.0
Torque Specification
70 ft-lbs (95 N·m)
Important Notes
These bolts secure the differential housing to the chassis or subframe. Ensure proper alignment before tightening. Estimated Value
2

Differential Drain/Fill Plug

M18 x 1.5
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
Use a new sealing washer or o-ring on the plug. Do not overtighten to prevent damage to the differential case.

Axles

1

Drive Axle/Half Shaft Bolts

M10 x 1.5
Torque Specification
1. 30 ft-lbs (41 N·m) 2. 60 ft-lbs (81 N·m)
Important Notes
Tighten bolts evenly in a circular pattern. These bolts secure the axle to the transmission or differential and wheel hubs.
2

CV Joint/Axle Nut

M24 x 1.5
Torque Specification
185 ft-lbs (251 N·m)
Important Notes
Use a new nut and ensure it's properly seated before tightening. Proper torque is crucial for wheel bearing preload and axle retention.

Transfer Case

1

Transfer Case Drain/Fill Plug

M18 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a new sealing washer or o-ring on the plug. Do not overtighten to prevent damage to the transfer case.

Electrical

Torque specifications for Electrical

Ignition System

1

Ignition Coil Mounting Bolt

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Ensures secure mounting and proper grounding of the ignition coil to the engine. Over-tightening may damage the coil housing.

Starting System

1

Starter Motor Mounting Bolt

M10 x 1.5
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
Ensures the starter motor is properly aligned and securely mounted to the engine. Provides a good ground connection for proper operation.

Charging System

1

Alternator Mounting Bolt

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensures the alternator is properly aligned and secured. Critical for proper belt alignment and alternator grounding.
2

Battery Terminal Nut

M8 x 1.25 (estimated)
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Ensures a solid electrical connection between battery cable and battery terminal. Over-tightening can damage the terminal. Value is estimated.

Engine Control Unit

1

ECU Mounting Bolt/Nut

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Secures the ECU to the vehicle. Proper torque is critical for ground connection and prevents damage to the ECU. Value is estimated.

Grounding System

1

Ground Strap Mounting Bolt/Nut (Small)

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Ensures proper electrical connection between components and the chassis. Proper torque is vital for a low resistance ground. Value is estimated.
2

Ground Strap Mounting Bolt/Nut (Large)

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensures proper electrical connection between components and the chassis. Proper torque is vital for a low resistance ground. Value is estimated.

Power Distribution

1

Fuse Box/Power Distribution Module Mounting Bolt/Nut

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Securely mounts the fuse box/power distribution module to the vehicle. Essential for ground connection and proper circuit protection. Value is estimated.

Sensor System

1

Sensor Mounting Bolt (Small)

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Secures various sensors to the engine or chassis. Avoid over-tightening which can damage sensor housing or affect readings. Value is estimated.
2

Sensor Mounting Bolt (Medium)

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Secures various sensors to the engine or chassis. Avoid over-tightening which can damage sensor housing or affect readings. Value is estimated.

Wiring Harness

1

Wiring Harness/Connector Mounting Screw

Self-Tapping Screw (Estimated)
Torque Specification
N/A
Important Notes
Hand-tight plus 1/4 turn. Over-tightening can damage the wiring or connector. These are frequently self-tapping screws that do not use a specific torque value. Estimated values are provided, but 'hand-tight and 1/4 turn' is preferred.

Emissions Sensors

Torque specifications for Emissions_sensors

Exhaust Manifold

1

Exhaust Manifold to Cylinder Head Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure proper and even tightening to prevent leaks.
2

Exhaust Manifold/Headers Bolts

M10 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Ensure proper and even tightening to prevent leaks and ensure manifold is properly sealed. These bolts connect manifold sections to each other.
3

Pre-Catalytic Oxygen (O2) Sensor

M18 x 1.5
Torque Specification
32 ft-lbs (43 N·m)
Important Notes
Apply anti-seize to sensor threads. Estimated value based on typical O2 sensor torque.
4

Exhaust Gas Temperature (EGT) Sensor

M12 x 1.5
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Apply anti-seize to sensor threads. Estimated value based on typical EGT sensor torque.

Catalytic Converter

1

Catalytic Converter to Exhaust Pipe Bolts

M10 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Ensure a leak-free seal for proper sensor readings.
2

Post-Catalytic Oxygen (O2) Sensor

M18 x 1.5
Torque Specification
32 ft-lbs (43 N·m)
Important Notes
Apply anti-seize to sensor threads. Estimated value based on typical O2 sensor torque.

Egr System

1

EGR Valve Mounting Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Proper torque prevents vacuum leaks.

Intake System

1

Mass Air Flow (MAF) Sensor Mounting Bolts

M5 x 0.8
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Ensure the MAF sensor is mounted securely, preventing air leaks and misreadings. Estimated value based on similar sensor mounting.

Nox System

1

Nitrogen Oxide (NOx) Sensor Mounting Bolts

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Ensure sensor is mounted securely for proper readings. Estimated value based on similar sensor mounting.

Dpf System

1

Differential Pressure Sensor Mounting Bolts

M5 x 0.8
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Secure sensor mounting is crucial for accurate readings. Estimated value based on similar sensor mounting.

Exhaust

Torque specifications for Exhaust

Exhaust Manifold

1

Exhaust Manifold/Headers to Cylinder Head Bolts

M8 x 1.25
Torque Specification
1. 10 ft-lbs (14 N·m) 2. 18 ft-lbs (24 N·m)
Important Notes
Tighten in a criss-cross pattern starting from the center bolts and working outwards. Apply torque in two steps.
2

Exhaust Pipe to Exhaust Manifold/Headers Bolts

M10 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a new gasket. Ensure bolts are tightened evenly.

Catalytic Converter

1

Catalytic Converter to Exhaust Pipe Bolts

M10 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a new gasket for proper sealing.

Muffler

1

Muffler to Exhaust Pipe Bolts

M10 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a new gasket to prevent leaks.

Support Brackets

1

Exhaust Hanger Bracket Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Estimated value. Ensure proper alignment before tightening.

Exhaust Clamps

1

Exhaust Clamp Bolts

M8 x 1.25
Torque Specification
35 ft-lbs (47 N·m)
Important Notes
Tighten evenly to ensure a leak-free seal. Ensure clamp is properly seated around the piping.
2

V-Band Clamp Bolts/Nuts

M6 x 1.0
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Tighten evenly to prevent clamp distortion and leaks.

Sensors

1

Oxygen Sensor Torque

M18 x 1.5
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Do not overtighten as it can crack the sensor. Always use anti-seize when applicable

Fuel

Torque specifications for Fuel

Fuel Rail Assembly

1

Fuel Rail Mounting Bolts

M6 x 1.0
Torque Specification
9 ft-lbs (12 N·m)
Important Notes
Ensure proper alignment of the fuel rail before tightening. Use a crisscross pattern when tightening bolts.
2

Fuel Injector Mounting Bolts

M5 x 0.8
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Be careful not to damage the injectors when installing or tightening the bolts. Proper seating of injector O-rings is critical.
3

Fuel Line Fittings on Fuel Rail and Injectors

Varies, typically M14 x 1.5 banjo bolt
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Estimated torque value. Confirm with BMW specific documentation based on the exact fitting size. Use new sealing washers or crush washers when installing.
4

Fuel Pressure Regulator Mounting Bolts

M5 x 0.8
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Estimated value. This assumes small bolts used to mount the regulator. Tighten evenly to ensure proper sealing.

Fuel Pump Assembly

1

Fuel Pump Mounting Bolts

M8 x 1.25
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Tighten bolts evenly to ensure proper pump sealing. Verify proper pump seal or o-ring is installed.
2

Fuel Filter Mounting Bolts

M8 x 1.25
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Verify proper alignment of the fuel filter to prevent strain on the lines. Ensure the filter is fully seated on its mounts.
3

Fuel Tank Sending Unit Bolts

M5 x 0.8
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Estimated value. Do not overtighten these small bolts. Ensure the gasket or O-ring is properly seated.
4

Fuel Tank Level Sensor Retaining Bolts

M5 x 0.8
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Estimated value. Do not overtighten these small bolts. Ensure the sensor is properly seated in the tank.

Fuel Tank And Filler

1

Fuel Filler Neck Mounting Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Tighten evenly to ensure proper seal between filler neck and body.

Hvac

Torque specifications for Hvac

Ac Compressor

1

A/C Compressor Mounting Bolts

M8 x 1.25
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
Ensure mounting surfaces are clean and free of debris. Apply even pressure when tightening.

Ac Lines

1

A/C Line Fittings

Variable - typically M12 x 1.5 or M14 x 1.5
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Use new o-rings or seals, lubricated with refrigerant oil. Overtightening may cause damage.

Ac Condenser

1

A/C Condenser Mounting Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Tighten bolts evenly to avoid bending or damaging the condenser. This value is an estimate, check service manual.

Ac Receiver Drier

1

A/C Receiver Drier/Accumulator Mounting Bolts/Bracket Bolts

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Do not overtighten the mounting bolts. This value is an estimate, check service manual.

Evaporator Core

1

Evaporator Core Housing Bolts

M5 x 0.8
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Do not overtighten, as this can crack the plastic housing. This value is an estimate, check service manual.

Blower Motor

1

Blower Motor Mounting Bolts

M5 x 0.8
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Do not overtighten, as this can crack the plastic housing. This value is an estimate, check service manual.

Hvac Control Unit

1

HVAC Control Unit Mounting Bolts/Screws

M4 x 0.7
Torque Specification
5 ft-lbs (7 N·m)
Important Notes
Do not overtighten. This value is an estimate, check service manual.

Mode Door Actuator

1

Mode Door Actuator Mounting Screws

M4 x 0.7
Torque Specification
2 ft-lbs (3 N·m)
Important Notes
Do not overtighten. This value is an estimate, check service manual.

Suspension

Torque specifications for Suspension

Front Suspension

1

Upper Strut Mount Nut/Bolt (Chassis Side)

M10 x 1.5
Torque Specification
1. 35 ft-lbs (47 N·m) 2. 90°
Important Notes
Always replace these bolts when removed. Torque to the specified value, then turn an additional 90 degrees.
2

Lower Strut Mount Bolts (Steering Knuckle Side)

M14 x 1.5
Torque Specification
75 ft-lbs (102 N·m)
Important Notes
Ensure the strut is properly seated in the steering knuckle before tightening. Always replace these bolts when removed.
3

Control Arm Bolts

M14 x 1.5
Torque Specification
85 ft-lbs (115 N·m)
Important Notes
Tighten these bolts with the vehicle at ride height to ensure correct bushing preload.
4

Ball Joint Nut

M12 x 1.5
Torque Specification
75 ft-lbs (102 N·m)
Important Notes
Ensure the ball joint stud is properly seated in the steering knuckle before tightening.
5

Tie Rod End Nut

M12 x 1.5
Torque Specification
55 ft-lbs (75 N·m)
Important Notes
Ensure the tie rod end is properly seated in the steering knuckle. If a castellated nut, always align with the cotter pin hole.
6

Sway Bar Link Nut

M10 x 1.5
Torque Specification
40 ft-lbs (54 N·m)
Important Notes
Ensure the sway bar link is properly aligned before tightening.
7

Steering Knuckle/Hub Carrier Mounting Bolts

M12 x 1.5
Torque Specification
75 ft-lbs (102 N·m)
Important Notes
Ensure the steering knuckle is properly aligned before tightening. Always replace these bolts when removed.

Rear Suspension

1

Rear Trailing Arm Bolts (Chassis Side)

M14 x 1.5
Torque Specification
1. 85 ft-lbs (115 N·m) 2. 90°
Important Notes
Always replace these bolts when removed. Torque to the specified value, then turn an additional 90 degrees.
2

Rear Trailing Arm Bolts (Hub Carrier/Knuckle Side)

M14 x 1.5
Torque Specification
1. 75 ft-lbs (102 N·m) 2. 90°
Important Notes
Always replace these bolts when removed. Torque to the specified value, then turn an additional 90 degrees.
3

Steering Knuckle/Hub Carrier Mounting Bolts

M12 x 1.5
Torque Specification
75 ft-lbs (102 N·m)
Important Notes
Ensure the hub carrier is properly aligned with the suspension components before tightening.

Sway Bar

1

Sway Bar Mounting Bracket Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure the sway bar is centered before tightening the brackets.

Ride Height Sensor

1

Ride Height Sensor Link Nut

M6 x 1.0
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Do not over-tighten. These components can be fragile.

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

What are the recommended torque specifications for lug nuts on a 2018-Present BMW 640i?

According to BMW, the recommended torque specification for lug nuts on a 2018-Present BMW 640i IS 140 Nm (103 lb-ft).

Q2

What type of torque wrench IS best suited for tightening lug nuts on a 2018-Present BMW 640i?

A calibrated torque wrench with a 1/2-inch drive IS recommended for tightening lug nuts on a 2018-Present BMW 640i. Ensure the torque wrench IS set to the specified torque value of 140 Nm (103 lb-ft).

Q3

IS it necessary to use a torque wrench when tightening bolts and nuts on a 2018-Present BMW 640i?

Yes, using a torque wrench IS crucial for tightening bolts and nuts on a 2018-Present BMW 640i. Over- or under-tightening can lead to component failure or damage. Always refer to the BMW workshop manual for specific torque specifications.

Q4

What IS the torque specification for the oil drain plug on a 2018-Present BMW 640i?

The torque specification for the oil drain plug on a 2018-Present BMW 640i IS 25 Nm (18 lb-ft).

Q5

Can I use an impact wrench to tighten lug nuts on my 2018-Present BMW 640i?

No, using an impact wrench to tighten lug nuts on a 2018-Present BMW 640i IS not recommended. Impact wrenches can over-tighten lug nuts, potentially damaging the wheels or brake components. Always use a calibrated torque wrench to ensure proper torque application.

Q6

What are some common torque mistakes to avoid when working on my 2018-Present BMW 640i?

Common torque mistakes include using the wrong torque value, over-tightening, under-tightening, and using an inaccurate torque wrench. Always consult the BMW workshop manual for specific torque specifications, follow tightening procedures carefully, and ensure your torque wrench IS calibrated.

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

BMW Genuine Torque Wrench

Recommended for precision torque application on BMW vehicles, ensuring proper tension and preventing damage.

  • Factory-calibrated for accuracy
  • Covers the torque range required for 640i maintenance
  • Durable construction for long-lasting use
Learn more

Digital Angle Torque Adapter

Essential for tightening critical bolts that require both torque and angle specifications.

  • Combines a digital torque wrench with an angle sensor
  • Precisely measures and applies torque while tracking the angle of rotation
  • Eliminates guesswork and ensures proper tightening
Learn more
Service Procedures

BMW 640i Engine Bolt Tightening Sequence

Step-by-step guide to properly tighten engine bolts in the correct sequence and torque specifications.

  • Safety precautions and preparation
  • Bolt tightening sequence diagram
  • Torque specifications for each bolt
  • Additional notes and considerations
View full procedure

BMW 640i Suspension Component Torque Specifications

Comprehensive guide to suspension torque specifications, ensuring proper alignment and performance.

  • Torque values for control arms, tie rods, ball joints, and other suspension components
  • Specific instructions for different suspension configurations
  • Safety precautions and warnings
View full procedure
Technical Service Bulletins

BMW TSB: Incorrect Engine Bolt Torque Specifications

2019-06-12

Important notice addressing an error in earlier torque specifications for certain engine bolts.

2018-2020 640i

Resolution: Updated torque values and detailed instructions to correct the issue

BMW TSB: Suspension Bolt Recall

2022-10-05

Safety recall notice regarding insufficiently tightened suspension bolts.

2019-2022 640i

Resolution: Instructions for inspection and tightening of affected bolts to ensure vehicle safety

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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.
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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.

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