BMW Vehicle Models 840i 2018-present Torque Specifications
BMW Vehicle Models 840i 2018-present

BMW Vehicle Models 840i 2018-present Torque Specifications

Complete BMW Vehicle Models 840i 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

Search Specifications

Search by component name, bolt size, or description

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. 15 ft-lbs (20 N·m) 2. 90° 3. 90° 4. 90°
Important Notes
Torque bolts in the proper sequence. Use new bolts. Angle torque after initial torque.

Crankshaft And Bottom End

1

Main Bearing Bolts

M10 x 1.5
Torque Specification
48 ft-lbs (65 N·m)
Important Notes
Tighten main bearing bolts in the proper sequence. Proper torque is crucial for oil clearance and crankshaft stability.
2

Connecting Rod Nuts

M8 x 1.25
Torque Specification
32 ft-lbs (43 N·m)
Important Notes
Tighten in a cross pattern to ensure even pressure.
3

Flywheel Bolts

M12 x 1.5
Torque Specification
74 ft-lbs (100 N·m)
Important Notes
Tighten flywheel bolts in a star pattern to ensure even pressure distribution.
4

Crankshaft Pulley/Harmonic Balancer Bolt

M16 x 1.5
Torque Specification
148 ft-lbs (200 N·m)
Important Notes
Use a new bolt. Proper torque is critical for secure pulley attachment.

Oil System

1

Oil Pan Bolts

M6 x 1
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Tighten oil pan bolts in a cross-pattern sequence to ensure an even seal.
2

Oil Filter Cap

N/A
Torque Specification
N/A
Important Notes
Hand Tighten. Do not over tighten, as this may cause damage to the oil filter cap and housing, and cause leaks.
3

Oil Filter Housing Bolt

N/A
Torque Specification
N/A
Important Notes
Hand Tighten. Do not over tighten, as this may cause damage to the oil filter cap and housing, and cause leaks.
4

Oil Drain Plug Bolt

M14 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a new washer. Do not over-tighten to prevent stripping of the threads.

Valvetrain

1

Valve Cover Bolts

M6 x 1
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Tighten valve cover bolts in a cross-pattern sequence to ensure even pressure.
2

Camshaft Bearing Cap Bolts (Initial Torque)

M8 x 1.25
Torque Specification
1. 8 ft-lbs (11 N·m) 2. 90°
Important Notes
Tighten the camshaft bearing caps evenly in sequence, followed by an angle torque step. Proper clamping force is critical to camshaft function and avoiding damage.
3

Camshaft Sprocket Bolt

M10 x 1.5
Torque Specification
63 ft-lbs (85 N·m)
Important Notes
Ensure proper camshaft timing before tightening.
4

Rocker Arms/Shafts Bolts

M6 x 1
Torque Specification
16 ft-lbs (22 N·m)
Important Notes
Tighten evenly in sequence
5

Variable Valve Timing (VVT) Actuator Bolts

M6 x 1
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Tighten evenly in sequence

Timing System

1

Timing Belt/Chain Tensioner Bolt

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Proper torque maintains timing accuracy. Ensure proper timing before tightening.

Intake And Exhaust

1

Intake Manifold Bolts

M6 x 1
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Tighten intake manifold bolts in a cross-pattern sequence to ensure an even seal.
2

Intake Manifold Support Bracket Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Tighten support bracket evenly
3

Exhaust Manifold/Headers to Cylinder Head Bolts

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Tighten exhaust manifold bolts in a cross pattern to ensure even pressure. Use new gaskets.
4

Throttle Body Bolts

M6 x 1
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Tighten throttle body bolts evenly.
5

EGR Valve Bolts

M6 x 1
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Tighten evenly.

Fuel System

1

Fuel Rail Bolts

M6 x 1
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Tighten fuel rail bolts evenly to ensure proper sealing and fuel pressure.
2

Fuel Injector Bolts

M5 x 0.8
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Tighten fuel injector bolts evenly to ensure a proper seal. Do not overtighten.

Ignition System

1

Spark Plugs

M14 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Proper torque is important to ensure proper combustion sealing and electrical contact. Use new plugs.
2

Ignition Coil Bolt

M6 x 1
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Tighten the ignition coil bolts to ensure they are properly secured and grounded.

Cooling System

1

Water Pump Bolts

M6 x 1
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Tighten water pump bolts in a cross-pattern sequence to ensure even sealing and prevent leaks.
2

Water Pump Pulley Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Tighten evenly.
3

Thermostat Housing Bolts

M6 x 1
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Tighten thermostat housing bolts in a cross-pattern sequence to ensure proper sealing.
4

Engine Coolant Drain Plug Bolt

M12 x 1.5
Torque Specification
11 ft-lbs (15 N·m)
Important Notes
Use a new washer. Do not over-tighten to prevent stripping of the threads.

8hp Transmission

Torque specifications for 8hp Transmission

Transmission Mounting

1

Transmission Mounting Bolts

M12 x 1.75
Torque Specification
48 ft-lbs (65 N·m)
Important Notes
Ensure proper alignment before tightening. Use new bolts if specified by the vehicle manufacturer. Torque in a star pattern if applicable.

Transmission Oil Pan

1

Transmission Oil Pan Bolts

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Use a criss-cross or star pattern when tightening to ensure even pressure on the gasket or sealant. Aluminum pans are particularly sensitive to overtightening.

Transmission Drain Fill Plugs

1

Transmission Drain and Fill Plugs

M18 x 1.5
Torque Specification
29 ft-lbs (40 N·m)
Important Notes
Use new sealing washers or O-rings if specified. Do not over-tighten, as this can damage the case threads.

Drive Axle Half Shaft

1

Drive Axle/Half Shaft Bolts

M10 x 1.5
Torque Specification
63 ft-lbs (85 N·m)
Important Notes
Inspect bolts for damage before installation. Some applications may require the use of new bolts and thread locker.

Mechatronic Unit

1

Mechatronic Unit Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Tighten bolts in a specific sequence (often a star pattern) to ensure even pressure. These bolts are typically low-torque, as the mechatronic unit is made of aluminum.

Valve Body

1

Valve Body Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Tighten these bolts in a specified sequence to ensure even pressure on the valve body. These bolts are typically low-torque.

Transmission Oil Cooler Lines

1

Transmission Oil Cooler Line Fittings

Varies (Estimate: M14 x 1.5)
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Torque values vary depending on the specific fitting type. This is an estimated value. Always refer to your vehicle’s service manual for specific instructions. Over-tightening can damage the fittings.

Transmission Bellhousing

1

Transmission Bellhousing Bolts

M10 x 1.5 (Estimated)
Torque Specification
44 ft-lbs (60 N·m)
Important Notes
Torque values can vary depending on the specific model and bolt size. This is an estimated value based on typical bolt sizes and applications. Always refer to your vehicle’s service manual. Use a star pattern for final tightening.

Mechatronic Connector

1

Transmission Mechatronic Connector Bolts/Screws

M4 x 0.7
Torque Specification
2 ft-lbs (3 N·m)
Important Notes
These are very low-torque fasteners; over-tightening can damage the connector or strip threads. Tighten only until snug.

Body

Torque specifications for Body

Wheels And Tires

1

Wheel Lug Nuts

M14 x 1.25
Torque Specification
88 ft-lbs (120 N·m)
Important Notes
Tighten lug nuts in a star pattern.

Fuel System

1

Fuel Tank Strap Bolts

M8 x 1.25
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
Ensure fuel tank is properly positioned before tightening.
2

Fuel Filler Neck Bolts

M6 x 1.0
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Ensure proper alignment of the filler neck with the fuel door.

Electrical System

1

Battery Terminal Nuts

M6 x 1.0
Torque Specification
5 ft-lbs (7 N·m)
Important Notes
Do not overtighten. Ensure terminals are clean.

Doors

1

Door Hinge Bolts (Body Side) - M10

M10 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Check door alignment after tightening.
2

Door Hinge Bolts (Body Side) - M8

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Check door alignment after tightening.
3

Door Hinge Bolts (Body Side) - M6

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Check door alignment after tightening.

Hood

1

Hood Hinge Bolts - M8

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure proper hood alignment after tightening.
2

Hood Hinge Bolts - M6

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Ensure proper hood alignment after tightening.

Exterior Panels

1

Fender Bolts - M8

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure proper fender alignment before tightening.
2

Fender Bolts - M6

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Ensure proper fender alignment before tightening.
3

Bumper Mounting Bolts - M8

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure proper bumper alignment before tightening. Check for bracket specific bolts.
4

Bumper Mounting Bolts - M6

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Ensure proper bumper alignment before tightening. Check for bracket specific bolts.

Lighting

1

Tail Light/Headlight Mounting Bolts/Nuts

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Do not overtighten. Ensure proper alignment.

Interior

1

Seat Mounting Bolts

M10 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure proper seat positioning. Check safety after install.
2

Dashboard Mounting Bolts/Screws

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Ensure proper alignment of the dashboard.
3

Interior Trim Panel Fasteners

Plastic Trim Fastener
Torque Specification
6 ft-lbs (8 N·m)
Important Notes
Do not overtighten. These are typically plastic clips or low-torque fasteners. Estimated value.

Roof

1

Sunroof Frame Bolts

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Ensure proper sealing and alignment of the sunroof frame.

Side Panels

1

Side Skirt/Rocker Panel Bolts

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Ensure proper alignment of the rocker panel. Plastic clips should be hand tight only.

Rear Panels

1

Rear Deck/Shelf Mounting Bolts/Screws

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Ensure proper alignment of rear deck.

Brakes

Torque specifications for Brakes

Front Caliper

1

Caliper Mounting Bolts

M12 x 1.5
Torque Specification
81 ft-lbs (110 N·m)
Important Notes
These bolts secure the caliper to the mounting bracket. Ensure proper seating and even torque.
2

Brake Pad Guide Pins/Bolts

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Secures the brake pads within the caliper. Over-tightening can cause binding. Value is estimated based on typical M8 bolt.
3

Brake Line Banjo Bolt (at Caliper)

M10 x 1.0
Torque Specification
23 ft-lbs (31 N·m)
Important Notes
Connects the brake line to the caliper. Use new crush washers and torque evenly to prevent leaks.
4

Caliper Bleeder Screw

M7 x 1.0
Torque Specification
9 ft-lbs (12 N·m)
Important Notes
Used for brake bleeding. Do not over-tighten to avoid damage to the soft metal. Value estimated

Rear Caliper

1

Caliper Mounting Bolts

M12 x 1.5
Torque Specification
81 ft-lbs (110 N·m)
Important Notes
Same torque as front caliper bracket bolts.
2

Brake Pad Guide Pins/Bolts

M8 x 1.25
Torque Specification
17 ft-lbs (23 N·m)
Important Notes
Slightly less than front caliper guide pins. Value is estimated based on typical M8 bolt.
3

Brake Line Banjo Bolt (at Caliper)

M10 x 1.0
Torque Specification
23 ft-lbs (31 N·m)
Important Notes
Use new crush washers when tightening, and be careful to avoid leaks.
4

Caliper Bleeder Screw

M7 x 1.0
Torque Specification
9 ft-lbs (12 N·m)
Important Notes
Same torque as front caliper bleeder screw. Do not over-tighten to avoid damage to the soft metal. Value estimated.

Mounting Brackets

1

Front Caliper Mounting Bracket Bolts

M14 x 1.5
Torque Specification
81 ft-lbs (110 N·m)
Important Notes
Secure the bracket to the steering knuckle.
2

Rear Caliper Mounting Bracket Bolts

M12 x 1.75
Torque Specification
81 ft-lbs (110 N·m)
Important Notes
Secure the bracket to the wheel hub or suspension component.

Rotor Retention

1

Brake Rotor Retaining Bolt

M8 x 1.25
Torque Specification
81 ft-lbs (110 N·m)
Important Notes
Retains the rotor while the wheel is not mounted. Value may be high, as it is shared with the Caliper Mounting Bolts.

Brake Lines

1

Brake Hose Bracket Bolts

M6 x 1.0
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Secures brake hose brackets to suspension or chassis. Value is estimated.

Abs Sensors

1

ABS Sensor Bolt (Front/Rear)

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Secures the ABS sensor to the wheel hub or knuckle.

Drivetrain

Torque specifications for Drivetrain

Engine Interface

1

Flywheel Bolts

M12 x 1.5
Torque Specification
74 ft-lbs (100 N·m)
Important Notes
Use a star pattern sequence for tightening. Ensure threads are clean and lightly lubricated with engine oil. Always replace if removed.

Transmission

1

Transmission Mounting Bolts

M10 x 1.5
Torque Specification
48 ft-lbs (65 N·m)
Important Notes
These bolts secure the transmission to the engine block. Ensure proper alignment before tightening. Use a cross tightening pattern. Always replace if removed.
2

Transmission Oil Pan Bolts

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Tighten in a cross pattern to ensure even gasket compression. Do not overtighten as it may cause gasket leaks.
3

Transmission Drain and Fill Plugs

M18 x 1.5
Torque Specification
29 ft-lbs (40 N·m)
Important Notes
Use new crush washers for the drain and fill plugs. Do not overtighten.
4

Transmission to Transfer Case Bolts

M10 x 1.5
Torque Specification
48 ft-lbs (65 N·m)
Important Notes
Estimated value. This applies to AWD models only. Ensure proper alignment before tightening. Use a cross tightening pattern. Always replace if removed.

Drive Axles

1

Drive Axle/Half Shaft Bolts

M10 x 1.5
Torque Specification
63 ft-lbs (85 N·m)
Important Notes
These bolts secure the drive axle to the transmission or wheel hub. Ensure the bolts are lightly lubricated before installing. Use a cross tightening pattern.
2

CV Joint/Axle Nut

M24 x 1.5
Torque Specification
148 ft-lbs (200 N·m)
Important Notes
This nut secures the CV joint to the wheel hub. It is critical for proper bearing preload. Use a new axle nut whenever removed.

Driveshaft

1

Propeller/Drive Shaft Bolts (Front)

M10 x 1.5
Torque Specification
74 ft-lbs (100 N·m)
Important Notes
Use a cross pattern for tightening the bolts evenly. Ensure bolts are lightly lubricated before installing. Always replace if removed.
2

Rear Driveshaft Flange Bolts (Connecting to the Differential)

M10 x 1.5
Torque Specification
74 ft-lbs (100 N·m)
Important Notes
Ensure proper alignment of the driveshaft to the differential flange. Use a cross pattern for tightening the bolts evenly. Always replace if removed.

Differential

1

Differential Mounting Bolts

M12 x 1.75
Torque Specification
74 ft-lbs (100 N·m)
Important Notes
Estimated value. Torque these bolts in a cross pattern to ensure even pressure. Always replace if removed.
2

Differential Drain/Fill Plug

M22 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Always use new crush washers for the drain and fill plugs. Do not overtighten.

Transfer Case

1

Transfer Case Drain/Fill Plug

M18 x 1.5
Torque Specification
29 ft-lbs (40 N·m)
Important Notes
Always use new crush washers for the drain and fill plugs. Do not overtighten.

Electrical

Torque specifications for Electrical

Ignition System

1

Ignition Coil Mounting Bolt

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Ensure proper seating of the coil before tightening. Do not overtighten, as this can damage the coil housing.

Starting System

1

Starter Motor Mounting Bolt

M10 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure the starter motor is properly aligned before tightening. Confirm there is no engine interference.

Charging System

1

Alternator Mounting Bolt

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Check for proper alignment and belt tension after installation. Ensure there is no belt or pulley interference.

Battery System

1

Battery Terminal Nut

M6 x 1.0
Torque Specification
5 ft-lbs (7 N·m)
Important Notes
Do not overtighten the terminal nuts as this can damage the battery posts. Ensure proper contact is made between the terminal and battery.

Engine Management

1

Engine Control Unit (ECU) Mounting Bolt

M6 x 1.0
Torque Specification
7 ft-lbs (9.5 N·m)
Important Notes
Estimated value. Do not overtighten. Ensure ECU is flush to mounting surface and properly grounded.
2

Crankshaft Position Sensor Mounting Bolt

M6 x 1.0
Torque Specification
7 ft-lbs (9.5 N·m)
Important Notes
Estimated value. Ensure proper sensor alignment and seating. Do not overtighten, as this can damage sensor housing.
3

Camshaft Position Sensor Mounting Bolt

M6 x 1.0
Torque Specification
7 ft-lbs (9.5 N·m)
Important Notes
Estimated value. Ensure proper sensor alignment and seating. Do not overtighten, as this can damage sensor housing.
4

Mass Airflow (MAF) Sensor Mounting Screw

M5 x 0.8
Torque Specification
5 ft-lbs (6.8 N·m)
Important Notes
Estimated value. Ensure the MAF sensor is correctly oriented. Do not overtighten, as this can damage sensor housing. Often this is a thread-forming screw, so be extra careful.

Grounding System

1

Ground Strap/Cable Mounting Bolt

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Estimated value. Ensure a clean, paint-free contact surface for the ground connection. Use a star washer when applicable.

Power Distribution

1

Relay Box/Fuse Box Mounting Bolt

M6 x 1.0
Torque Specification
10 ft-lbs (13.5 N·m)
Important Notes
Estimated value. Ensure the box is properly aligned and grounded. Do not overtighten, as this can damage the mounting brackets.

Emissions Sensors

Torque specifications for Emissions_sensors

Exhaust System

1

Exhaust Manifold/Headers to Cylinder Head Bolts

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Ensure proper torque sequence when tightening manifold bolts. Refer to service manual for specific pattern.
2

Exhaust Manifold/Headers to Exhaust Pipe Connection Bolts

M10 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure proper alignment of exhaust components before tightening. Use new gaskets.
3

Catalytic Converter to Exhaust Pipe Connection Bolts

M10 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Use new gaskets to ensure proper sealing.

Egr System

1

EGR Valve Mounting Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Use new gaskets or seals when replacing the EGR valve.

Oxygen Sensors

1

Heated Oxygen Sensor Mounting (Typical)

M18 x 1.5
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
Use a new crush washer/gasket. Torque may vary, always refer to manufacturer specs. This is an estimated value based on typical M18 O2 sensor.
2

Heated Oxygen Sensor Mounting (Smaller Size)

M12 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Use a new crush washer/gasket. Torque may vary, always refer to manufacturer specs. This is an estimated value based on typical M12 O2 sensor.

Nox Sensors

1

NOx Sensor Mounting Bolts/Studs

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure proper sensor alignment. This value is estimated based on typical sensor bolt sizes.

Air Intake System

1

Mass Air Flow (MAF) Sensor Mounting Bolts

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Do not overtighten, as MAF sensor housings are often made from plastic. This is an estimated value for a typical MAF sensor.
2

Intake Air Temperature (IAT) Sensor Mounting

N/A (Threaded Connection)
Torque Specification
N/A
Important Notes
Many IAT sensors are threaded with an o-ring and should be hand-tightened until snug. Do not over-tighten. Do not use excessive torque.

Differential Pressure Sensors

1

Differential Pressure Sensor Mounting Bolts

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Ensure proper sensor alignment. This is an estimated value for typical sensor bolts.

Exhaust

Torque specifications for Exhaust

Exhaust Manifold

1

Exhaust Manifold/Headers to Cylinder Head Bolts

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Use a criss-cross pattern when tightening to ensure even pressure.
2

Exhaust Manifold/Headers to Exhaust Pipe Bolts

M10 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Apply anti-seize to bolt threads.

Catalytic Converter

1

Catalytic Converter to Exhaust Pipe Bolts

M10 x 1.5
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
Ensure proper alignment of flanges before tightening.

Muffler

1

Muffler to Exhaust Pipe Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Use new gaskets if applicable.

Exhaust Hangers

1

Exhaust Hanger Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure hangers are properly aligned before tightening.

O2 Sensor

1

O2 Sensor

M18 x 1.5
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
Apply anti-seize to threads. Do not over-tighten.

Exhaust Flange Studs

1

Exhaust Flange Stud Nuts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
If studs are present, tighten nuts to this value. Use anti-seize.

Exhaust Clamps

1

Exhaust Clamp Bolts

M8 x 1.25
Torque Specification
23 ft-lbs (31 N·m)
Important Notes
Tighten clamps evenly. Estimated value.

Fuel

Torque specifications for Fuel

Fuel Rail

1

Fuel Rail Mounting Bolts

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
These bolts secure the fuel rail to the intake manifold or cylinder head. Ensure bolts are tightened evenly.
2

Fuel Injector Mounting Bolts

M5 x 0.8
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
These bolts secure the fuel injectors to the fuel rail or intake manifold. Do not overtighten.
3

Fuel Line Banjo Bolt (Fuel Rail)

M8 x 1.25
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
Secures the fuel line to the fuel rail. Always use new crush washers and ensure correct orientation. Value is an estimate based on typical M8 banjo bolts.

Fuel Pump

1

Fuel Pump Mounting Bolts

M6 x 1.0
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
These bolts secure the fuel pump module to the fuel tank or mounting bracket. Tighten evenly.

Fuel Filter

1

Fuel Filter Mounting Bolts/Nuts

M6 x 1.0
Torque Specification
14 ft-lbs (19 N·m)
Important Notes
Secures the fuel filter housing or bracket. These bolts tend to be a smaller size, approximately 6 or 8 mm.

Fuel Filler

1

Fuel Filler Neck Mounting Bolts

M6 x 1.0
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Secures the fuel filler neck to the fuel tank or vehicle body. Tighten evenly. Bolts can be either 6mm or 8mm.

Fuel Tank

1

Fuel Tank Sending Unit Mounting Bolts

M6 x 1.0
Torque Specification
6 ft-lbs (8 N·m)
Important Notes
Secures the fuel tank sending unit to the fuel tank. Do not overtighten. Typically 6 or 8mm bolts.
2

Fuel Tank Sending Unit Lock Ring

N/A
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
Secures the fuel tank sending unit to the fuel tank. Use a lock ring tool to tighten. Estimated value. Torque can vary based on lock ring type.

Fuel Line Fittings

1

Fuel Line Quick Connect Fittings

N/A
Torque Specification
N/A
Important Notes
Quick-connect fittings require a click to confirm proper engagement. Do not overtighten or force.
2

Fuel Line Clamp Connections

N/A
Torque Specification
1. 2. 90°
Important Notes
Clamp connections should be hand-tightened and then a specified amount of turn with a tool. Approximately 90 degrees of a turn after hand-tight is usually sufficient. Do not overtighten.

Hvac

Torque specifications for Hvac

Ac Compressor

1

A/C Compressor Mounting Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure the compressor is properly aligned before tightening. Check for proper fitment.

Ac Lines

1

A/C Line Fittings

Varies, typically M10 x 1.0 or M12 x 1.5
Torque Specification
13 ft-lbs (18 N·m)
Important Notes
Always use new o-rings/seals and lubricate with A/C compressor oil before assembly to ensure proper sealing. Torque values may vary slightly depending on fitting size.

Ac Condenser

1

A/C Condenser Mounting Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensure condenser is correctly positioned to prevent interference with other components. It is recommended to follow the manufacturer's tightening sequence.

Ac Evaporator

1

A/C Evaporator Housing Bolts

M5 x 0.8
Torque Specification
6 ft-lbs (8 N·m)
Important Notes
These bolts secure the evaporator housing. It is important to maintain a proper seal to ensure efficiency of the system. Use a low range torque wrench.

Ac Expansion Valve

1

A/C Expansion Valve Mounting Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Proper torque is essential to prevent leaks at the expansion valve connections and ensure accurate refrigerant flow. Ensure proper alignment.

Hvac Control Panel

1

HVAC Control Panel Mounting Bolts

M4 x 0.7
Torque Specification
4 ft-lbs (5 N·m)
Important Notes
These bolts are small and require a low torque value to prevent damage to the plastic housing of the control panel. Use a low range torque wrench.

Blower Motor

1

Blower Motor Housing Bolts

M5 x 0.8
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Proper torque ensures no air leaks around the blower motor housing and reduces vibrations. Ensure the housing is properly aligned before tightening.

Hvac Unit Mounting

1

HVAC Unit Mounting Bolts

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
These bolts are critical for the overall integrity of the system, preventing unwanted movement and vibrations. Follow a tightening sequence if specified in the service manual.

Suspension

Torque specifications for Suspension

Strut Shock Absorber

1

Strut/Shock Absorber Lower Mounting Bolts

M12 x 1.5
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
These bolts secure the strut or shock absorber to the steering knuckle or wheel carrier. Ensure proper alignment before tightening.
2

Strut Top Mount Bolts

M8 x 1.25
Torque Specification
16 ft-lbs (22 N·m)
Important Notes
These bolts secure the top of the strut/shock absorber assembly to the vehicle's body or chassis. Failure to torque these can cause suspension noise and/or damage to components.

Control Arms

1

Control Arm Bolts (Chassis Side)

M14 x 1.5
Torque Specification
48 ft-lbs (65 N·m)
Important Notes
These bolts secure the control arm to the vehicle's chassis. Tighten with the vehicle at ride height to ensure proper bushing preload.
2

Steering Knuckle To Lower Control Arm Bolt

M14 x 1.5
Torque Specification
1. 74 ft-lbs (100 N·m) 2. 90°
Important Notes
These bolts connect the lower control arm to the steering knuckle. This connection typically requires a torque angle spec as well, not just a standard torque. This is a critical connection for both suspension and steering of the vehicle.

Steering Components

1

Ball Joint Nut

M12 x 1.25
Torque Specification
63 ft-lbs (85 N·m)
Important Notes
This nut secures the ball joint stud to the steering knuckle. Do not over-tighten.
2

Tie Rod End Nut

M10 x 1.25
Torque Specification
33 ft-lbs (45 N·m)
Important Notes
This nut secures the tie rod end to the steering knuckle. Ensure the tie rod is correctly positioned to prevent misalignment.

Sway Bar

1

Sway Bar Link Nut

M10 x 1.5
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
These nuts connect the sway bar links to the strut or control arm. Ensure the links are positioned correctly before tightening.
2

Sway Bar Bushing Bracket Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
These bolts secure the sway bar bushing brackets to the vehicle's frame or chassis. Do not over-tighten to prevent damage to bushings.

Brake System

1

Brake Caliper Bolts

M12 x 1.75
Torque Specification
81 ft-lbs (110 N·m)
Important Notes
These bolts secure the brake caliper to the steering knuckle or caliper bracket. Ensure proper alignment of the caliper over the rotor before tightening. Note the thread locker being used.
2

Brake Caliper Mounting Bracket Bolts

M12 x 1.75
Torque Specification
81 ft-lbs (110 N·m)
Important Notes
These bolts secure the caliper bracket to the steering knuckle. Note the thread locker being used.

Wheel Speed Sensor

1

Wheel Speed Sensor Mounting Bolt/Screw

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
These bolts secure the wheel speed sensor to the steering knuckle. Do not over-tighten to avoid damaging the sensor.

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 torque specifications for the lug nuts on a 2018-Present BMW 840i?

The torque specification for the lug nuts on a 2018-Present BMW 840i IS 90 ft-lbs (122 Nm).

Q2

What are the torque specifications for the oil drain plug on a 2018-Present BMW 840i?

The torque specification for the oil drain plug on a 2018-Present BMW 840i IS 25 ft-lbs (34 Nm).

Q3

What are the torque specifications for the spark plugs on a 2018-Present BMW 840i?

The torque specification for the spark plugs on a 2018-Present BMW 840i IS 18 ft-lbs (24 Nm).

Q4

What IS the recommended torque wrench for use on a 2018-Present BMW 840i?

BMW recommends using a torque wrench with a range of 20-200 ft-lbs (27-271 Nm) for use on a 2018-Present BMW 840i.

Q5

What are the signs of over-torquing a bolt?

Signs of over-torquing a bolt include: stripping of the threads, bolt head damage, and/or component damage.

Q6

What are the consequences of under-torquing a bolt?

Consequences of under-torquing a bolt include: loose or rattling components, premature wear, and/or component failure.

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 840i.

  • 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

Cylinder Head Bolt Tightening Procedure

Step-by-step guide to properly tighten cylinder head bolts on the BMW 840i engine, ensuring optimal performance and preventing damage.

  • Clean all mating surfaces and apply a thin layer of engine oil to the threads of the bolts.
  • Tighten the bolts in the correct sequence and to the specified torque values, using a digital torque wrench.
  • Re-torque the bolts after the engine has cooled to room temperature.
View full procedure
Technical Service Bulletins

Technical Service Bulletin: Suspension Bolt Torque Specifications

2021-06-15

Updates torque specifications for suspension components on 2018-Present BMW 840i models to address premature wear and noise issues.

2018-2020 840i 2021-Present 840i

Resolution: Refer to the updated torque specifications provided in the bulletin and ensure proper tightening during suspension repairs and maintenance.

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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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