BMW Vehicle Models 640i 2011-2018 Torque Specifications
BMW Vehicle Models 640i 2011-2018

BMW Vehicle Models 640i 2011-2018 Torque Specifications

Complete BMW Vehicle Models 640i 2011-2018 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 (Initial Torque)

M12 x 1.75
Torque Specification
1. 25 ft-lbs (34 N·m) 2. 90° 3. 90°
Important Notes
Torque to 25 ft-lbs (34 N·m), then angle tighten 90 degrees, then another 90 degrees. Use new torque-to-yield bolts. Refer to OEM specific manual for torque sequence.
2

Camshaft Bearing Cap Bolts

M8 x 1.25
Torque Specification
12 ft-lbs (16 N·m)
Important Notes
Estimated value based on typical M8 bolt. Check OEM manual for specific torque sequence and value.
3

Rocker Arm/Shaft Bolts

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Ensure proper valve lash adjustment after tightening.

Engine Block

1

Main Bearing Bolts

M10 x 1.5
Torque Specification
40 ft-lbs (54 N·m)
Important Notes
Follow a proper torque sequence. Apply engine oil to the threads before installing. New bolts are generally recommended.
2

Oil Pan Bolts

M6 x 1.0
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Tighten bolts in a criss-cross pattern to ensure even pressure on the gasket. Do not overtighten.
3

Timing Chain Tensioner Bolt

M8 x 1.25
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Ensure proper timing chain tension after tightening.
4

Timing Chain Guide Bolts

M6 x 1.0
Torque Specification
12 ft-lbs (16 N·m)
Important Notes
Estimated value based on typical M6 bolt. Check OEM manual for proper sequence and torque value.
5

Oil Filter Housing Bolt

Plastic Cap
Torque Specification
N/A
Important Notes
Hand Tight. Do not overtighten, to avoid damage to the threads.
6

Oil Drain Plug Bolt

M14 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a new sealing washer. Do not overtighten.
7

Water Pump Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensure proper gasket alignment. Tighten bolts in a criss-cross pattern.
8

Water Pump Pulley Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensure the pulley is properly seated.
9

Thermostat Housing Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensure proper gasket or O-ring alignment.
10

Coolant Temperature Sensor Torque

M12 x 1.5
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Use a new sensor washer. Do not overtighten.

Crankshaft

1

Flywheel Bolts

M12 x 1.5
Torque Specification
60 ft-lbs (81 N·m)
Important Notes
Use new bolts. Apply thread locker. Ensure proper alignment of the flywheel.
2

Crankshaft Pulley/Harmonic Balancer Bolt

M14 x 1.5
Torque Specification
90 ft-lbs (122 N·m)
Important Notes
Use new bolt. Apply thread locker. Ensure proper pulley alignment.

Connecting Rods

1

Connecting Rod Nuts

M9 x 1.0
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Apply engine oil to the threads and under the nut before installing. Use new nuts and bolts are recommended. Check for proper rod bearing clearances.

Intake System

1

Throttle Body Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensure proper gasket alignment. Do not overtighten.
2

Intake Manifold Bolts

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Tighten bolts in a criss-cross pattern to ensure even gasket compression. Do not overtighten.
3

PCV Valve Bolts/Screws

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Estimated value based on typical M6 bolt. Ensure proper O-ring or gasket is used.

Exhaust System

1

Exhaust Manifold/Headers Bolts

M8 x 1.25
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a new gasket. Tighten bolts in a criss-cross pattern.
2

EGR Valve Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensure proper gasket or O-ring is installed correctly.

Fuel System

1

Fuel Rail Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensure proper fuel rail alignment.
2

Fuel Injector Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Ensure proper O-ring alignment. Do not overtighten.

Ignition System

1

Spark Plugs

M14 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Use a spark plug socket for proper installation. Do not overtighten.
2

Ignition Coil Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensure coils are seated properly and connected to the wiring harness.

Accessory Drive

1

Serpentine/Accessory Drive Belt Tensioner Bolt

M8 x 1.25
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Ensure proper belt tension after installation.
2

Drive Belt Idler Pulley Bolt

M8 x 1.25
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Ensure the pulley spins freely after installation.

Vanos System

1

VANOS Solenoid Bolts/Screws

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Estimated value based on typical M6 bolt, use a new O-ring.

Valve Cover

1

Valve Cover Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Use a new gasket. Tighten bolts in a criss-cross pattern. Do not overtighten.

Camshaft

1

Camshaft Sprocket Bolt

M10 x 1.25
Torque Specification
50 ft-lbs (68 N·m)
Important Notes
Ensure proper engine timing is set before installation. Refer to OEM manual for specific procedures.

8hp Transmission

Torque specifications for 8hp Transmission

Transmission Mounting

1

Transmission Mounting Bolts

M12 x 1.75
Torque Specification
35 ft-lbs (47 N·m)
Important Notes
Ensure all bolts are tightened evenly to prevent distortion. Check for proper alignment during installation. Value estimated based on common M12 bolt applications.

Transmission Oil Pan

1

Transmission Oil Pan Bolts

M6 x 1.0
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Tighten bolts in a cross pattern to ensure even sealing. Do not overtighten as this can cause damage. Use a new gasket for proper sealing. Value estimated based on typical M6 bolt applications.

Transmission Drain Fill Plugs

1

Transmission Drain/Fill Plug

M18 x 1.5
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Ensure the sealing washer is in good condition, if applicable, to prevent leaks. Do not over-tighten as it can damage the threads. Value estimated based on typical drain plug applications.
2

Transmission Overflow Plug

M14 x 1.5
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Ensure the sealing washer is in good condition, if applicable, to prevent leaks. Do not over-tighten as it can damage the threads. Value estimated based on typical overflow plug applications.

Mechatronic Unit

1

Mechatronic Unit Mounting Bolts

M6 x 1.0
Torque Specification
1. 6 ft-lbs (8 N·m)
Important Notes
Tighten bolts in a star pattern to ensure even clamping. A multi-step tightening procedure is essential. Be very careful to not over-torque these bolts. Value estimated based on typical M6 bolt applications in sensitive areas.

Valve Body

1

Valve Body Mounting Bolts

M6 x 1.0
Torque Specification
1. 6 ft-lbs (8 N·m)
Important Notes
Tighten bolts in a star pattern to ensure even sealing and valve operation. A multi-step tightening procedure is essential. Be very careful to not over-torque these bolts. Value estimated based on typical M6 bolt applications in sensitive areas.

Bellhousing To Engine

1

Bellhousing to Engine Bolts

M12 x 1.75
Torque Specification
1. 30 ft-lbs (40 N·m) 2. 90°
Important Notes
Tighten bolts in a specific sequence, often a cross-pattern. It is common to torque to a specific value and then apply an angle. Always use new, high quality bolts with the correct grade for this application. Value estimated and includes an angle tightening, as this is very common for structural bolts.

Torque Converter

1

Torque Converter to Flywheel Bolts

M10 x 1.5
Torque Specification
45 ft-lbs (60 N·m)
Important Notes
Apply a thread-locking compound to the bolt threads. Torque these bolts carefully and evenly. Value estimated based on common M10 applications.

Oil Cooler Line Fittings

1

Transmission Oil Cooler Line Fittings

M16 x 1.5
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Do not overtighten these fittings, as this could cause damage to the fittings or lines. If the fittings are banjo type, follow a multi-step tightening procedure. Check for leaks after tightening. Value estimated based on common hydraulic fitting applications.

Body

Torque specifications for Body

Wheel System

1

Wheel Lug Nuts

M14 x 1.25
Torque Specification
90 ft-lbs (122 N·m)
Important Notes
Ensure lug nuts are tightened in a star pattern.

Fuel System

1

Fuel Tank Strap Bolts

M8 x 1.25
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Ensure fuel tank is properly positioned before tightening.
2

Fuel Filler Neck Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Do not over-tighten these bolts as they attach to thin metal.

Hood System

1

Hood Hinge Bolts to Hood

M6 x 1.0
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure proper alignment of hood before tightening bolts. Estimated value.
2

Hood Hinge Bolts to Body

M8 x 1.25
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
Ensure hood is properly aligned before tightening. Estimated value.

Body Panels

1

Fender Bolts to Body

M6 x 1.0
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Ensure proper fender alignment before tightening bolts. Estimated value.
2

Bumper Cover Mounting Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Do not over-tighten as they attach to plastic components. Estimated value.

Door System

1

Door Hinge Bolts to Door

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Ensure proper door alignment before tightening bolts. Estimated value.
2

Door Hinge Bolts to Body

M10 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Ensure door is properly aligned before tightening. Estimated value.
3

Door Latch Bolts

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Ensure latch is properly aligned for smooth door operation. Estimated value.

Trunk System

1

Trunk/Boot Lid Hinge Bolts to Lid

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Ensure proper alignment of lid before tightening. Estimated value.
2

Trunk/Boot Lid Hinge Bolts to Body

M10 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Ensure trunk is properly aligned before tightening. Estimated value.

Lighting System

1

Tail Light Housing Bolts/Screws

M5 x 0.8
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Do not over-tighten, as these attach to plastic. Estimated value.
2

Headlight Housing Bolts/Screws

M5 x 0.8
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Do not over-tighten, as these attach to plastic. Estimated value.

Exterior Components

1

Side Mirror Mounting Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Do not over-tighten these bolts. Estimated value.

Interior Components

1

Seat Mounting Bolts

M10 x 1.5
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Ensure proper seat alignment before tightening. Estimated value.
2

Interior Trim Screws/Fasteners

Various
Torque Specification
5 ft-lbs (7 N·m)
Important Notes
Use a low torque setting to prevent damage to interior trim. Estimated value.

Brakes

Torque specifications for Brakes

Brake Caliper

1

Brake Caliper Mounting Bolts

M12 x 1.5
Torque Specification
85 ft-lbs (115 N·m)
Important Notes
These bolts secure the caliper to the mounting bracket. Ensure proper torque for secure caliper positioning.
2

Brake Caliper Guide Pin Bolts/Screws

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
These bolts secure the guide pins, which allow the caliper to float. Proper torque is critical for even pad wear.
3

Brake Caliper Bleeder Valve

M10 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensure proper sealing during brake bleeding. Overtightening can damage the valve; use a torque wrench.

Caliper Bracket

1

Brake Caliper Mounting Bracket Bolts

M14 x 1.5
Torque Specification
130 ft-lbs (176 N·m)
Important Notes
These bolts secure the mounting bracket to the steering knuckle or hub carrier. High torque is required to withstand braking forces.

Brake Rotor

1

Brake Disc/Rotor Retaining Bolts

M12 x 1.5
Torque Specification
100 ft-lbs (136 N·m)
Important Notes
These bolts secure the brake rotor to the hub, ensuring it remains firmly in place. Proper torque is critical to prevent rotor from being loose.

Brake Lines

1

Brake Line Fittings (at Caliper)

M10 x 1.0
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Approximate value; confirm if different. Essential for preventing leaks. Avoid overtightening.
2

Brake Line Fittings (at Master Cylinder)

M12 x 1.0
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Approximate value; confirm if different. Essential for preventing leaks. Avoid overtightening.

Brake Pad Sensor

1

Brake Pad Wear Sensor Screw

M4 x 0.7
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
These small screws secure the wear sensor to the pad. Overtightening can cause damage. Estimated Value.

Abs Sensor

1

ABS Sensor Mounting Bolts

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
These bolts secure the ABS sensor to the knuckle or hub. Low torque is needed to prevent damage. Estimated Value.

Drivetrain

Torque specifications for Drivetrain

Engine Flywheel

1

Flywheel to Crankshaft Bolts

M12 x 1.25
Torque Specification
60 ft-lbs (81 N·m)
Important Notes
Ensure mating surfaces are clean. Apply a thin layer of anti-seize compound to bolt threads if specified by the manufacturer.
2

Flex Plate to Crankshaft Bolts

M12 x 1.25
Torque Specification
1. 60 ft-lbs (81 N·m) 2. 60°
Important Notes
Ensure mating surfaces are clean. Apply a thin layer of anti-seize compound to bolt threads if specified by the manufacturer. Final torque is achieved through a combination of torque and angle tightening.
3

Torque Converter to Flex Plate Bolts

M10 x 1.25
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Ensure mating surfaces are clean and that the torque converter is properly seated to the flexplate. Verify the correct bolt length is used, excessively long bolts can cause damage.

Transmission Mounting

1

Transmission Mounting Bolts

M12 x 1.75
Torque Specification
35 ft-lbs (47 N·m)
Important Notes
Ensure proper alignment of transmission before tightening. Use new bolts if recommended by manufacturer.

Transmission Service

1

Transmission Oil Pan Bolts

M6 x 1.0
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Tighten in a criss-cross pattern to avoid warping the pan. Always use a new gasket for proper sealing.
2

Transmission Drain and Fill Plugs

M22 x 1.5
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Use a new sealing washer or O-ring to ensure a proper seal.

Drive Axles

1

Drive Axle/Half Shaft Bolts

M10 x 1.5
Torque Specification
80 ft-lbs (108 N·m)
Important Notes
Ensure the drive axle is properly seated before tightening.
2

CV Joint/Axle Nut

M24 x 1.5
Torque Specification
210 ft-lbs (285 N·m)
Important Notes
This nut often requires a very high torque and should be torqued with the vehicle's wheels on the ground. Always replace the nut with a new one.
3

Drive Axle to Differential Flange Bolts

M10 x 1.5
Torque Specification
60 ft-lbs (81 N·m)
Important Notes
Estimated value based on similar bolt sizes. Ensure mating surfaces are clean. Apply a thin layer of anti-seize compound to bolt threads if specified by the manufacturer.

Driveshaft

1

Propeller/Drive Shaft Bolts

M10 x 1.5
Torque Specification
70 ft-lbs (95 N·m)
Important Notes
Ensure proper alignment of the drive shaft before tightening. Use new bolts if recommended by manufacturer. Some applications may use a self locking nut, and those should always be replaced.
2

Transmission Output Shaft Flange Bolts

M10 x 1.5
Torque Specification
45 ft-lbs (61 N·m)
Important Notes
Estimated value based on similar bolt sizes. Ensure mating surfaces are clean. Apply a thin layer of anti-seize compound to bolt threads if specified by the manufacturer.

Differential

1

Differential Drain/Fill Plug

M20 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a new sealing washer or O-ring to ensure a proper seal.
2

Differential Mounting Bolts

M14 x 2.0
Torque Specification
60 ft-lbs (81 N·m)
Important Notes
Estimated value based on similar bolt sizes. Ensure proper alignment of differential before tightening. Use new bolts if recommended by manufacturer.

Transfer Case

1

Transfer Case Drain/Fill Plug

M20 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a new sealing washer or O-ring to ensure a proper seal.

Electrical

Torque specifications for Electrical

Ignition System

1

Ignition Coil Mounting Bolt

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensures proper electrical grounding and secure mounting. Over-torquing may damage the coil or mounting points. These are generally low-torque applications.

Starting System

1

Starter Motor Mounting Bolt

M10 x 1.5
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Secures the starter to the engine block or transmission. Proper torque is crucial for reliable mechanical connection and electrical grounding. Over-tightening can crack the mounting boss or threads on the engine block.

Charging System

1

Alternator Mounting Bolt

M10 x 1.5
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Secures the alternator to the engine. Ensures proper belt alignment for charging, and provides a reliable ground connection. Over-tightening can crack the mounting bosses or threads. This bolt will also ground the alternator.

Battery System

1

Battery Terminal Nut

M8 x 1.25
Torque Specification
5 ft-lbs (7 N·m)
Important Notes
Secures the battery cables to the battery terminals, crucial for maintaining good electrical connection for all vehicle systems. Over-torquing can damage the battery terminals.

Engine Management

1

Engine Control Unit (ECU) Mounting Bolt

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
These bolts secure the ECU to the vehicle body or engine bay. Improper torque can lead to vibrations, poor grounding, or damage to the ECU casing. This is a low torque application.

Grounding System

1

Ground Strap/Cable Bolt (Engine/Chassis)

M8 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Connects grounding straps/cables from the engine and chassis to the body. Proper torque is essential for good electrical connection. Ensure both mating surfaces are free of corrosion before tightening.

Electrical Distribution

1

Fuse Box Mounting Bolt

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Secures the fuse box and relay box to the body. Ensures the fuse box has proper grounding connections.
2

Body Control Module (BCM) Mounting Bolt

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Secures the BCM to the body or interior. Must maintain proper grounding for reliable operation. This is a low torque application.

Emissions Sensors

Torque specifications for Emissions_sensors

Exhaust System

1

Exhaust Gas Recirculation (EGR) Valve Bolts

M8 x 1.25
Torque Specification
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 Specification
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 Specification
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 Specification
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 Specification
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 Specification
6 ft-lbs (8 N·m)
Important Notes
Estimated value based on typical small sensor mounting bolt size. Confirm with OEM specifications.

Intake System

1

Mass Air Flow (MAF) Sensor Bolts

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

Fuel System

1

Fuel Injector Bolts

M6 x 1.0
Torque Specification
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 Specification
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

1

Evaporative Emissions (EVAP) Canister Mounting Bolts

M8 x 1.25
Torque Specification
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 Specification
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

1

Crankcase Ventilation Valve (PCV Valve) bolts/screws

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

Exhaust

Torque specifications for Exhaust

Exhaust Manifold

1

Exhaust Manifold/Header to Cylinder Head Nuts

M8 x 1.25 (estimated)
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a star pattern when tightening. Estimated bolt size. Always use new gaskets. Apply anti-seize to stud threads. Ensure proper alignment before tightening. These typically use studs and nuts, and the torque applies to the nuts.
2

Exhaust Pipe to Exhaust Manifold/Header Bolts

M10 x 1.5 (estimated)
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a star pattern when tightening. Estimated bolt size. Always use a new gasket. Apply anti-seize to bolt threads. This connection could be studs with nuts, or bolts that attach to a flange.

Catalytic Converter

1

Catalytic Converter to Exhaust Pipe Bolts

M10 x 1.5 (estimated)
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a star pattern when tightening. Estimated bolt size. Always use a new gasket. Apply anti-seize to bolt threads.

Muffler

1

Muffler to Exhaust Pipe Clamp Bolts

M8 x 1.25 (estimated)
Torque Specification
35 ft-lbs (47 N·m)
Important Notes
Estimated bolt size. Torque to the middle of the range. Do not over-tighten. Check for proper seal. This connection often uses a slip fit with a clamping system that is secured by these bolts.

Exhaust Clamps

1

Exhaust Pipe Clamp Bolts

M8 x 1.25 (estimated)
Torque Specification
35 ft-lbs (47 N·m)
Important Notes
Estimated bolt size. This value is an estimated middle of range value; refer to the clamp manufacturer's specification if available. Do not over-tighten these, as it will damage the clamp. Ensure the clamp is fully seated on the pipe prior to tightening.

Oxygen Sensors

1

Oxygen Sensor (O2 Sensor) Install Torque

M18 x 1.5 (estimated)
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Estimated thread size. Ensure new sensor has an intact crush washer. Do not over-tighten. The threads on the sensor also require proper torque to prevent leaks and ensure proper operation of the sensor. Too tight and it can damage the threads or sensor, too loose and it will cause exhaust leaks.

Exhaust Hangers

1

Exhaust Hanger Bracket Bolts

M8 x 1.25 (estimated)
Torque Specification
23 ft-lbs (31 N·m)
Important Notes
Estimated bolt size. This value is in the middle of a recommended range. Do not over-tighten. These bolts secure the exhaust hangers to the chassis or body of the car. It is important to not overtighten these as it will crush the bracket and can lead to failure. These are often different lengths and locations, so be sure to use the correct bolts.

Fuel

Torque specifications for Fuel

Fuel Rail

1

Fuel Rail Mounting Bolts

M8 x 1.25
Torque Specification
1. 5 ft-lbs (7 N·m) 2. 10 ft-lbs (14 N·m)
Important Notes
Tighten bolts in a criss-cross pattern. Torque in two steps, first to 5 ft-lbs, then to 10 ft-lbs.
2

Fuel Injector Mounting Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Ensure injectors are seated correctly before tightening. Do not overtighten.
3

Fuel Pressure Sensor Mounting Bolt

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Tighten to specified torque. Be careful not to overtighten, as this can damage the sensor. This value is an estimate.

Fuel Pump

1

Fuel Pump Mounting Bolts

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Ensure the fuel pump is properly seated before tightening. Use a criss-cross pattern when tightening multiple bolts.
2

High Pressure Fuel Pump Mounting Bolts

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Tighten to specified torque. Make sure that the pump is correctly located.

Fuel Tank

1

Fuel Tank Strap Bolts

M10 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Tighten fuel tank strap bolts to specified torque. Ensure straps are correctly positioned.
2

Fuel Filler Neck Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Tighten fuel filler neck bolts to specified torque to ensure a proper seal. Use a criss cross pattern when tightening multiple bolts.

Fuel Lines

1

Steel Banjo Bolt for Fuel Line

M12 x 1.5
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Always use new sealing washers. Torque to manufacturer specifications. This value is an estimate.
2

Compression Fitting for Fuel Line

Variable, check component specification
Torque Specification
13 ft-lbs (18 N·m)
Important Notes
Use a torque wrench to avoid over-tightening and crushing the fitting. This is an estimated value.
3

Quick Disconnect Fittings

N/A
Torque Specification
N/A
Important Notes
Hand-tighten only; listen for a 'click' to confirm they are locked on properly. No torque required.
4

Fuel Filter Mounting Bolt/Nut

M8 x 1.25
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
Tighten to specified torque. Ensure fuel filter is seated correctly before tightening.

Hvac

Torque specifications for Hvac

Ac Compressor

1

A/C Compressor Mounting Bolts

M10 x 1.5
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Ensure proper compressor alignment. Apply even torque to all bolts. Use a cross-tightening pattern.
2

A/C Line Fittings

Varies by location, estimate M8 x 1.25
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use new O-rings. Avoid over-tightening. Proper sealing is critical to prevent leaks. Estimated value, confirm in service manual.

Ac Condenser

1

Condenser Mounting Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Tighten evenly to avoid damage. Use a cross-tightening pattern. Ensure no kinks in lines.
2

Receiver Drier/Accumulator Mounting Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Tighten evenly to avoid leaks and vibration. Small bolts require careful torque application.

Ac Evaporator

1

Expansion Valve Mounting Bolts

M5 x 0.8
Torque Specification
7 ft-lbs (9 N·m)
Important Notes
Small bolts require low torque. Avoid over-tightening to prevent cracking of valve housing.
2

Evaporator Housing Bolts/Fasteners

M4 x 0.7
Torque Specification
5 ft-lbs (7 N·m)
Important Notes
These fasteners are often small, plastic or plastic with metal inserts and require a low torque. Tighten by hand until contact, plus 1/4 turn past contact.

Hvac Blower

1

Blower Motor Mounting Bolts/Screws

M5 x 0.8
Torque Specification
6 ft-lbs (8 N·m)
Important Notes
Tighten evenly to avoid vibration. Ensure no binding of blower fan. Avoid over-tightening.
2

HVAC Control Unit Mounting Screws

M4 x 0.7
Torque Specification
3 ft-lbs (4 N·m)
Important Notes
These are small screws that typically secure to plastic and require low torque values. Tighten by hand to snug fit and then a very small 1/4 turn past contact. Do not over-tighten.
3

Blend Door Actuator Mounting Screws

M4 x 0.7
Torque Specification
4 ft-lbs (5 N·m)
Important Notes
Avoid over-tightening to prevent damage to the actuator or plastic housing. Do not force the actuator, it should align easily.

Suspension

Torque specifications for Suspension

Front Strut Assembly

1

Upper Strut Mount to Chassis Bolts

M10 x 1.5
Torque Specification
40 ft-lbs (54 N·m)
Important Notes
Secure upper strut mount to the chassis. Ensure proper alignment of strut before tightening.
2

Lower Strut Mount to Steering Knuckle Bolts

M12 x 1.5
Torque Specification
1. 80 ft-lbs (108 N·m) 2. 90°
Important Notes
These bolts secure the strut to the steering knuckle. Angle torque is required. These are typically stretch bolts and must be replaced once removed.

Front Control Arms

1

Control Arm to Frame/Subframe Bolts

M14 x 2.0
Torque Specification
85 ft-lbs (115 N·m)
Important Notes
Secure control arms to frame or subframe. Ensure control arm is in its neutral position during tightening.
2

Ball Joint Nut

M12 x 1.5
Torque Specification
70 ft-lbs (95 N·m)
Important Notes
Secures the ball joint stud. Check for proper seating and align cotter pin hole if applicable. If a castle nut, install a new cotter pin after torquing.

Steering

1

Tie Rod End Nut

M12 x 1.25
Torque Specification
50 ft-lbs (68 N·m)
Important Notes
Secures the tie rod end to the steering knuckle. Ensure proper alignment and secure with a cotter pin if it is a castle nut.

Sway Bar

1

Sway Bar Link Nut

M10 x 1.25
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Secures the sway bar links to the sway bar and strut/control arm. Tighten with sway bar in its neutral position.
2

Sway Bar Mounting Bracket Bolts

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Mounting bolts for the sway bar bushings and brackets. Ensure bushings are properly seated before tightening.

Rear Suspension

1

Rear Lower Control Arm to Subframe Bolts

M14 x 2.0
Torque Specification
1. 100 ft-lbs (136 N·m) 2. 90°
Important Notes
These bolts secure the rear lower control arms to the subframe. Angle torque is required. These are typically stretch bolts and must be replaced once removed.
2

Rear Upper Control Arm to Subframe Bolts

M12 x 1.75
Torque Specification
1. 70 ft-lbs (95 N·m) 2. 90°
Important Notes
These bolts secure the rear upper control arms to the subframe. Angle torque is required. These are typically stretch bolts and must be replaced once removed.
3

Rear Wheel Hub Assembly Bolts/Nuts

M12 x 1.5
Torque Specification
85 ft-lbs (115 N·m)
Important Notes
Secure the rear wheel hub assembly to the body. Ensure proper mating of the surfaces.

Subframes

1

Front Subframe Bolts

M14 x 2.0
Torque Specification
1. 100 ft-lbs (136 N·m) 2. 90°
Important Notes
Secure the front subframe to the chassis. Angle torque is required. These are typically stretch bolts and must be replaced once removed. Tighten in a cross pattern.
2

Rear Subframe Bolts

M14 x 2.0
Torque Specification
1. 90 ft-lbs (122 N·m) 2. 90°
Important Notes
Secure the rear subframe to the chassis. Angle torque is required. These are typically stretch bolts and must be replaced once removed. Tighten in a cross pattern.

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 IS the recommended engine head bolt torque specification for a 2011-2018 BMW 640i?

According to BMW technical specifications, the engine head bolt torque for the N55 engine in the 2011-2018 BMW 640i IS 30 Nm (22 ft-lbs) plus an additional 90 degrees of rotation.

Q2

What IS the proper torque sequence for tightening the lug nuts on a BMW 640i?

Follow a star pattern, tightening the lug nuts to 140 Nm (103 ft-lbs) in the following sequence: 1-4-2-5-3.

Q3

What IS the torque specification for the oil drain plug on a 2011-2018 BMW 640i?

The oil drain plug on the N55 engine in the 2011-2018 BMW 640i should be tightened to 25 Nm (18 ft-lbs).

Q4

What type of torque wrench IS recommended for use with a BMW 640i?

For accurate torque measurements, use a calibrated click-type torque wrench that meets or exceeds DIN EN ISO 6789 standards.

Q5

How often should I check the torque on critical bolts and nuts on my BMW 640i?

BMW recommends checking torque on critical components, such as engine head bolts and suspension bolts, every 30,000 miles or 2 years, whichever comes first.

Q6

IS it safe to use an impact wrench when tightening bolts on a BMW 640i?

Using an impact wrench on critical bolts and nuts IS not recommended, as it can over-tighten and damage components. Use a calibrated torque wrench for precise tightening.

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

Digital Torque Wrench (10-100 Nm)

Essential for tightening fasteners to precise torque specifications, preventing damage and ensuring proper assembly. This range IS suitable for many applications on the 640i.

  • Digital display for accurate readings
  • Audible alarm when target torque IS reached
  • Multiple units (Nm, ft-lb, in-lb)
  • Reversible ratcheting mechanism
Learn more
Service Procedures
Technical Service Bulletins

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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.
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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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