BMW Vehicle Models 340i 2012-2018 Torque Specifications
BMW Vehicle Models 340i 2012-2018

BMW Vehicle Models 340i 2012-2018 Torque Specifications

Complete BMW Vehicle Models 340i 2012-2018 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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Search by component name, bolt size, or description

Torque Calculator

Convert between different torque units

3.0l Engine

Torque specifications for 3.0L Engine

Cylinder Head

1

Cylinder Head Bolts

M12 x 1.75
Torque Specification
1. 18 ft-lbs (25 N·m) 2. 90° 3. 90°
Important Notes
Torque in sequence, refer to specific service manual for pattern. Final steps are angle torques. Be sure to use new bolts and lubricate threads before installation.

Crankshaft

1

Main Bearing Bolts

M10 x 1.5
Torque Specification
1. 30 ft-lbs (40 N·m) 2. 60°
Important Notes
Torque in proper sequence. Angle torque is critical for proper clamping force.
2

Flywheel Bolts

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

Crankshaft Pulley/Harmonic Balancer Bolt

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

Connecting Rods

1

Connecting Rod Nuts

M9 x 1.25
Torque Specification
1. 30 ft-lbs (40 N·m) 2. 45°
Important Notes
Torque in sequence. Angle torque is critical for proper clamping force.

Oil System

1

Oil Pan Bolts

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

Oil Filter Cap

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

Oil Filter Housing Bolts

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

Oil Drain Plug Bolt

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

Valvetrain

1

Valve Cover Bolts

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

Timing Belt/Chain Tensioner Bolt

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

Camshaft Sprocket Bolts

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

Rocker Arms/Shafts Bolts

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

VANOS Solenoid Bolts

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

Ignition System

1

Spark Plugs

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

Ignition Coil Bolt

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

Intake System

1

Throttle Body Bolts

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

Intake Manifold Bolts

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

Fuel Injector Bolts

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

Fuel Injector Rail Bolts

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

Exhaust System

1

Exhaust Manifold/Headers Bolts

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

Cooling System

1

Water Pump Bolts

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

Water Pump Pulley Bolts

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

Thermostat Housing Bolts

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

Sensors

1

Knock Sensor Bolts

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

Crank Position Sensor Bolt

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

8hp Transmission

Torque specifications for 8hp Transmission

Transmission Mounting

1

Transmission Mounting Bolts

M12 x 1.75
Torque Specification
37 ft-lbs (50 N·m)
Important Notes
Ensure proper alignment before tightening. Use a cross tightening pattern.
2

Transmission Bell Housing to Engine Bolts

M12 x 1.75
Torque Specification
37 ft-lbs (50 N·m)
Important Notes
These bolts connect the transmission housing directly to the engine block. Ensure proper alignment.

Transmission Oil Pan

1

Transmission Oil Pan Bolts

M6 x 1.0
Torque Specification
7.4 ft-lbs (10 N·m)
Important Notes
Tighten in a star pattern to ensure even sealing. Do not overtighten as threads in the case can easily be damaged.

Fluid Plugs

1

Transmission Drain and Fill Plugs

M18 x 1.5
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
Use new sealing washers. Avoid over-tightening to prevent damage to the threads.

Mechatronics Unit

1

Mechatronics Unit Mounting Bolts

M6 x 1.0
Torque Specification
7.4 ft-lbs (10 N·m)
Important Notes
Tighten using a cross pattern to ensure proper sealing and prevent damage to the unit. These are typically very small, delicate bolts so they should never be over-tightened.

Valve Body

1

Valve Body Mounting Bolts

M6 x 1.0
Torque Specification
7.4 ft-lbs (10 N·m)
Important Notes
Tighten bolts in a star pattern to ensure even clamping force. Over-tightening can cause damage.

Cooler Lines

1

Transmission Cooler Line Fittings

Varies - check fitting type
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Torque value is an estimate. Always refer to the specific fitting manufacturer's recommendations. Ensure proper sealing and avoid over-tightening, as damage can easily occur.

Output Flange

1

Transmission Output Flange Bolts

M10 x 1.5
Torque Specification
48 ft-lbs (65 N·m)
Important Notes
Ensure the output flange is correctly aligned and seated against the transmission before tightening. Torque all bolts evenly.

Body

Torque specifications for Body

Fuel System

1

Fuel Tank Strap Bolts

M10 x 1.5
Torque Specification
27 ft-lbs (37 N·m)
Important Notes
Ensure proper alignment of straps before tightening. Check for even gap and secure fit.
2

Fuel Filler Neck Bolts

M6 x 1.0
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Do not over-tighten these bolts to prevent damage to the fuel filler neck.

Wheel System

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 to ensure even pressure. Always use a calibrated torque wrench.

Electrical System

1

Battery Terminal Nuts

M6 x 1.0
Torque Specification
5 ft-lbs (7 N·m)
Important Notes
Do not over-tighten battery terminal nuts as damage to the terminals may occur. Ensure terminals are clean and free of corrosion before installation.

Body Panels

1

Hood Hinge Bolts to Hood

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

Hood Hinge Bolts to Body

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Estimated value. Ensure proper hinge alignment to the body.
3

Fender Bolts to Body

M6 x 1.0
Torque Specification
9 ft-lbs (12 N·m)
Important Notes
Estimated value. Ensure proper fender alignment and gap spacing before tightening.
4

Door Hinge Bolts to Body

M8 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Estimated value. Ensure proper door alignment before tightening.
5

Door Hinge Bolts to Door

M8 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Estimated value. Ensure proper hinge alignment to the door.
6

Bumper Cover Mounting Bolts/Screws

M6 x 1.0
Torque Specification
6 ft-lbs (8 N·m)
Important Notes
Estimated value. Do not over-tighten to avoid damage to the bumper cover.
7

Headlight Mounting Bolts/Screws

M5 x 0.8
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Estimated value. Do not over-tighten to avoid cracking the headlight housing.
8

Tail Light Mounting Bolts/Screws

M5 x 0.8
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Estimated value. Do not over-tighten to avoid cracking the tail light housing.
9

Grill Mounting Bolts/Screws

M5 x 0.8
Torque Specification
6 ft-lbs (8 N·m)
Important Notes
Estimated value. Do not over-tighten to avoid damage to the grill.
10

Rear Hatch/Trunk Lid Hinge Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Estimated value. Ensure smooth operation and proper alignment of the hatch/trunk.

Interior

1

Seat Mounting Bolts to Floor Pan

M10 x 1.5
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
Estimated value. Ensure seats are properly aligned and secure.
2

Seat Belt Mounting Bolts to Body/Floor Pan

M10 x 1.5
Torque Specification
35 ft-lbs (47 N·m)
Important Notes
Estimated value. Critical for safety, must be properly secured.
3

Interior Trim Fasteners

M4 x 0.7 or equivalent
Torque Specification
2 ft-lbs (3 N·m)
Important Notes
Estimated value. Do not over-tighten as plastic may crack.

Exterior Accessories

1

Roof Rack Mounting Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Estimated value. Ensure the roof rack is properly aligned before tightening.
2

Side Mirror Mounting Bolts/Screws

M5 x 0.8
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Estimated value. Do not over-tighten, ensure proper mirror positioning.

Door Components

1

Door Lock Actuator Mounting Bolts/Screws

M5 x 0.8
Torque Specification
6 ft-lbs (8 N·m)
Important Notes
Estimated value. Ensure proper functionality after installation.
2

Door Handle Mounting Bolts/Screws

M5 x 0.8
Torque Specification
6 ft-lbs (8 N·m)
Important Notes
Estimated value. Ensure proper fit and operation of the door handle.

General

1

General Body Panel Fasteners

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Estimated value. Check the specific application to confirm correct fastener size and torque.

Brakes

Torque specifications for Brakes

Brake Caliper

1

Caliper Mounting Bolts

M12 x 1.5
Torque Specification
81 ft-lbs (110 N·m)
Important Notes
These bolts attach the caliper to the mounting bracket. Ensure proper tightening to prevent caliper movement.
2

Caliper Bleeder Screw

M10 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Tighten to seal, do not overtighten. This is an estimated value.
3

Brake Line Fitting (Caliper End)

M10 x 1.0
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Ensure proper fitting alignment. Torque value is estimated and may vary by fitting type.
4

Brake Pad Retaining Pins/Bolts

M8 x 1.25
Torque Specification
12 ft-lbs (16 N·m)
Important Notes
Ensure pins/bolts are properly engaged in the brake pads. This is an estimated value.

Caliper Mounting Bracket

1

Mounting Bracket Bolts

M14 x 1.5
Torque Specification
96 ft-lbs (130 N·m)
Important Notes
These bolts attach the bracket to the steering knuckle. Ensure proper tightening to maintain braking stability.

Brake Rotor

1

Rotor Retaining Bolt

M6 x 1.0
Torque Specification
12 ft-lbs (16 N·m)
Important Notes
These bolts secure the brake rotor to the wheel hub. This is an estimated value.

Wheel

1

Wheel Lug Nuts

M14 x 1.5
Torque Specification
88 ft-lbs (120 N·m)
Important Notes
Torque lug nuts in a star pattern to ensure even clamping.

Master Cylinder

1

Master Cylinder Mounting Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
These bolts secure the master cylinder to the booster. This is an estimated value.

Brake Booster

1

Brake Booster Mounting Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
These bolts secure the brake booster to the firewall. This is an estimated value.

Drivetrain

Torque specifications for Drivetrain

Engine Flywheel

1

Flywheel Bolts (Manual Transmission)

M12 x 1.5
Torque Specification
55 ft-lbs (75 N·m)
Important Notes
These bolts are often Torque-to-Yield (TTY) and should be replaced upon removal. Ensure surfaces are clean and free of debris. Apply a light coat of threadlocker if recommended by the service manual.
2

Flex Plate Bolts (Automatic Transmission)

M12 x 1.5
Torque Specification
55 ft-lbs (75 N·m)
Important Notes
These bolts are often Torque-to-Yield (TTY) and should be replaced upon removal. Ensure surfaces are clean and free of debris. Apply a light coat of threadlocker if recommended by the service manual.

Clutch Components

1

Clutch Pressure Plate Bolts

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Tighten bolts in a star pattern. Ensure the pressure plate is properly aligned with the flywheel before tightening. Use a calibrated torque wrench.
2

Clutch Slave Cylinder Bolts

M6 x 1.0
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Ensure the slave cylinder is properly seated before tightening. Do not overtighten as this could damage the cylinder or threads. Use a calibrated torque wrench.

Transmission

1

Transmission Mounting Bolts

M12 x 1.75
Torque Specification
37 ft-lbs (50 N·m)
Important Notes
Ensure transmission is properly aligned before tightening these bolts. Use a calibrated torque wrench. Apply threadlocker if recommended by service manual
2

Transmission Oil Pan Bolts

M6 x 1.0
Torque Specification
7.4 ft-lbs (10 N·m)
Important Notes
Tighten bolts in a star pattern to ensure even seal compression. Do not overtighten as this could damage the pan or threads.
3

Transmission Case Bolts

M10 x 1.5
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
Tighten bolts in a cross pattern to ensure even seal compression. Apply threadlocker if recommended by service manual.

Transmission Service

1

Transmission Drain and Fill Plugs

M18 x 1.5
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
Use a new sealing washer each time. Do not overtighten as this could damage the threads.

Driveshaft

1

Propeller/Drive Shaft Bolts (Transmission & Differential Flanges)

M10 x 1.5
Torque Specification
59 ft-lbs (80 N·m)
Important Notes
Ensure proper driveshaft alignment before tightening. Apply threadlocker if recommended by service manual.
2

Driveshaft Center Support Bearing Bolts

M8 x 1.25
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
Ensure bearing is properly aligned before tightening. Do not overtighten. Apply threadlocker if recommended by service manual.

Differential

1

Differential Output Flange Bolts (to Driveshaft/Axle)

M10 x 1.5
Torque Specification
59 ft-lbs (80 N·m)
Important Notes
These are often the same specification as the driveshaft bolts. Ensure proper flange alignment before tightening. Apply threadlocker if recommended by service manual.
2

Differential Drain/Fill Plug

M18 x 1.5
Torque Specification
37 ft-lbs (50 N·m)
Important Notes
Use a new sealing washer each time. Do not overtighten as this could damage the threads.

Transfer Case

1

Transfer Case Drain/Fill Plug

M18 x 1.5
Torque Specification
37 ft-lbs (50 N·m)
Important Notes
Use a new sealing washer each time. Do not overtighten as this could damage the threads.

Drive Axle

1

Drive Axle/Half Shaft Bolts (Transmission/Differential Side)

M10 x 1.5
Torque Specification
65 ft-lbs (88 N·m)
Important Notes
Ensure proper alignment before tightening. Apply threadlocker if recommended by the service manual.
2

CV Joint/Axle Nut (Wheel Hub Side)

M24 x 1.5
Torque Specification
214 ft-lbs (290 N·m)
Important Notes
This nut is often Torque-to-Yield (TTY) and should be replaced upon removal. Ensure proper wheel bearing preload and axle joint integrity. Use a calibrated torque wrench.

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 proper electrical contact and secure mounting of the ignition coil. Do not overtighten, as this could damage the coil or cylinder head.

Starting System

1

Starter Motor Mounting Bolt

M10 x 1.5
Torque Specification
37 ft-lbs (50 N·m)
Important Notes
Ensures proper alignment of the starter motor and a solid ground connection. Improper torque can lead to starter malfunction or damage.

Charging System

1

Alternator Mounting Bolt

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Ensures proper alignment of the alternator and a good electrical ground. Insufficient torque can cause misalignment, while excessive torque can damage the alternator or mounting points.

Battery System

1

Battery Terminal Nut

M6 x 1.0
Torque Specification
5 ft-lbs (7 N·m)
Important Notes
Ensures good electrical contact between the battery cables and terminals. Too little torque can lead to a poor connection, and too much torque may damage the terminals.

Engine Control Unit

1

ECU/DME Mounting Bolt

M5 x 0.8
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Ensures secure mounting of the ECU and protects sensitive electronic components. Use a criss-cross pattern to evenly tighten the bolts. This value is estimated based on typical M5 bolts.

Grounding System

1

Engine to Chassis Ground Strap Bolt (M8)

M8 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Provides a critical ground path for the entire electrical system. Ensure contact surfaces are clean. Improper torque can cause high resistance and electrical malfunction.
2

Engine to Chassis Ground Strap Bolt (M10)

M10 x 1.5
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
Provides a critical ground path for the entire electrical system. Ensure contact surfaces are clean. Improper torque can cause high resistance and electrical malfunction.

Sensor System

1

Crankshaft/Camshaft Position Sensor Mounting Bolt

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Ensures proper sensor alignment and grounding. Values estimated, actual sensor may vary slightly. Do not overtighten to avoid sensor damage.
2

Oxygen Sensor Mounting Bolt

M8 x 1.25
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensures proper sensor alignment and grounding. Values estimated, actual sensor may vary slightly. Do not overtighten, as this can damage the sensor or exhaust.

Wiring Harness

1

Wiring Harness Ground Point Bolt

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Ensures a solid ground connection for the wiring harness. Insufficient torque can lead to intermittent electrical issues, estimated values.

Emissions Sensors

Torque specifications for Emissions_sensors

Exhaust System

1

Exhaust Manifold to Cylinder Head Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Apply anti-seize lubricant to threads. Torque in a cross pattern.
2

Exhaust Pipe to Exhaust Manifold Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Apply anti-seize lubricant to threads. Torque in a cross pattern.
3

Catalytic Converter to Exhaust Pipe Bolts

M10 x 1.5
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Apply anti-seize lubricant to threads. Torque in a cross pattern.
4

Oxygen Sensor Mounting Stud/Bolt

M18 x 1.5
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Ensure sensor threads are clean. Torque value is estimated. May vary slightly by sensor location.
5

NOx Sensor Mounting Stud/Bolt

M16 x 1.5
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Ensure sensor threads are clean. Torque value is estimated. May vary slightly by sensor location.

Egr System

1

EGR Valve Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Torque bolts evenly to avoid warping the EGR valve.

Intake System

1

Mass Air Flow (MAF) Sensor Bolts

M5 x 0.8
Torque Specification
7.4 ft-lbs (10 N·m)
Important Notes
Do not overtighten; the MAF sensor housing is easily damaged. 10Nm is equal to about 89 in-lbs
2

Intake Air Temperature (IAT) Sensor Mounting Bolt/Clip

M4 x 0.7
Torque Specification
1.5 ft-lbs (2 N·m)
Important Notes
Hand-tighten only, if bolt-mounted. If clip-mounted, ensure the sensor is securely snapped into place. Torque value is estimated

Exhaust

Torque specifications for Exhaust

Exhaust Manifold

1

Exhaust Manifold/Headers to Cylinder Head Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
These bolts secure the manifold/headers to the cylinder head. Ensure proper torque to prevent exhaust leaks and maintain a secure seal. Use new gaskets when reinstalling.

Front Exhaust Pipe

1

Exhaust Pipe to Exhaust Manifold/Headers Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
These bolts fasten the exhaust pipe to the manifold/headers. Use new gaskets to avoid leaks.

Catalytic Converter

1

Catalytic Converter to Exhaust Pipe Bolts

M10 x 1.5
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Ensure proper torque to maintain a gas-tight seal at the catalytic converter connection. Use new gaskets if needed.

Muffler

1

Muffler to Exhaust Pipe Bolts

M10 x 1.5
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Proper torque here is important to prevent exhaust leaks and ensure proper alignment and support of the muffler. Use new gaskets when reinstalling.

Exhaust Clamps

1

Exhaust Flange/Band Clamps

Varies based on clamp - Estimated
Torque Specification
30 ft-lbs (40 N·m)
Important Notes
These torque values are estimates. Ensure proper alignment before tightening to avoid exhaust leaks. Check the clamp manufacturer's specifications for more precise values if available. Over-tightening may damage the pipes.

Exhaust Hangers

1

Exhaust Hanger Bolts/Nuts to Chassis

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Tighten these bolts/nuts to ensure the exhaust system is properly supported and prevent movement and noise. Use new hardware if necessary.

Oxygen Sensors

1

O2 Sensor

M18 x 1.5
Torque Specification
31 ft-lbs (42 N·m)
Important Notes
Tighten the sensor to prevent exhaust leaks and ensure a good sensor reading. Avoid over-tightening which can damage the sensor.

Egt Sensors

1

Exhaust Gas Temperature (EGT) Sensor

M14 x 1.5 - Estimated
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
These torque values are estimates based on similar-sized sensors. Ensure correct torque to prevent leaks and maintain accurate readings. Over-tightening can damage the sensor.

Fuel

Torque specifications for Fuel

Fuel Rail

1

Fuel Rail Mounting Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Ensure mating surfaces are clean. Over-tightening may damage the fuel rail or cylinder head/intake manifold threads.
2

Fuel Injector Mounting Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Ensure injector o-rings are properly lubricated. Over-tightening may damage injector or manifold threads.
3

Fuel Pressure Sensor Bolt

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Ensure sensor is seated properly. Over-tightening may damage the sensor.
4

High-Pressure Fuel Line Fitting (to Rail)

Varies (refer to fitting type)
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Torque value is an estimate. Always refer to the service manual for the exact fitting type and torque setting. Use a flare nut wrench to avoid damaging the fitting. Estimated value.

Fuel Pump

1

Fuel Pump Mounting Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (25 N·m)
Important Notes
Tighten bolts evenly to prevent pump flange warping.
2

Fuel Pump Module Retaining Ring

Special Tool (plastic or metal ring)
Torque Specification
50 ft-lbs (68 N·m)
Important Notes
This is an estimated average. Refer to the service manual for the specific value for your vehicle. Use appropriate tool to tighten the retaining ring, do not overtighten.
3

Fuel Tank Strap Bolts

M10 x 1.5
Torque Specification
27 ft-lbs (37 N·m)
Important Notes
Tighten evenly to ensure proper tank alignment.
4

Fuel Tank Sending Unit Bolts/Screws

M5 x 0.8
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Ensure proper alignment and do not over-tighten. These are generally smaller fasteners. Estimated value

Fuel Filler

1

Fuel Filler Neck Bolts

M6 x 1.0
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Do not over-tighten as this might damage the filler neck.

Fuel Filter

1

Fuel Filter Bolt/Nut

M6 x 1.0
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Ensure filter is seated correctly in its bracket, do not over-tighten

Hvac

Torque specifications for Hvac

Ac Compressor

1

Compressor Mounting Bolts

M10 x 1.5
Torque Specification
37 ft-lbs (50 N·m)
Important Notes
Ensure bolts are clean and lightly lubricated with engine oil prior to installation. Tighten all bolts to specified torque. Do not over tighten.

Ac Lines And Fittings

1

A/C Line Fittings

N/A - Fitting Specific
Torque Specification
13 ft-lbs (18 N·m)
Important Notes
Always use new o-rings or seals. Ensure fittings are properly aligned before tightening. Do not over tighten, as this can damage the seals or flare fitting.

Ac Condenser

1

Condenser Mounting Bolts

M6 x 1.0
Torque Specification
7.4 ft-lbs (10 N·m)
Important Notes
Ensure bolts are clean and threads are undamaged. Do not over tighten. Torque value is estimated based on similar mounting bolts.

Ac Evaporator

1

Evaporator Housing Bolts/Screws

M5 x 0.8
Torque Specification
7.4 ft-lbs (10 N·m)
Important Notes
Ensure all housing parts are aligned correctly before tightening bolts. Do not overtighten to avoid cracking plastic. Torque value is estimated based on similar components.

Blower Motor

1

Blower Motor Mounting Bolts/Screws

M5 x 0.8
Torque Specification
5.16 ft-lbs (7 N·m)
Important Notes
Ensure the blower motor is properly seated before tightening. Do not over tighten to avoid cracking plastic housing. Torque value is estimated based on similar components.

Hvac Control Module

1

HVAC Control Module Mounting Bolts/Screws

M4 x 0.7
Torque Specification
3.68 ft-lbs (5 N·m)
Important Notes
Be careful not to overtighten the screws. These are very small and easily stripped. Torque value is estimated based on similar components.

Blend Door Actuators

1

Air Distribution/Blend Door Actuator Mounting Screws

M4 x 0.7
Torque Specification
2 ft-lbs (3 N·m)
Important Notes
Actuators are typically mounted with small screws into plastic. Do not over tighten. Torque value is estimated based on similar components.

Expansion Valve

1

Expansion Valve Mounting Bolts/Screws

M6 x 1.0
Torque Specification
7.4 ft-lbs (10 N·m)
Important Notes
Ensure expansion valve is properly seated against the evaporator core or mounting point before tightening. Do not overtighten, which may damage the components. Torque value is estimated based on similar components.

Suspension

Torque specifications for Suspension

Front Strut Assembly

1

Strut Mounting Bolts to Chassis

M12 x 1.5
Torque Specification
81 ft-lbs (110 N·m)
Important Notes
Ensure the strut is properly aligned before final tightening. These bolts secure the upper strut mount to the vehicle's strut tower.
2

Strut Pinch Bolt to Steering Knuckle

M14 x 1.5
Torque Specification
52 ft-lbs (70 N·m)
Important Notes
This bolt secures the strut to the steering knuckle. Often a stretch bolt, replace if removed.

Front Control Arms

1

Control Arm Bolts to Subframe/Chassis

M14 x 1.5
Torque Specification
74 ft-lbs (100 N·m)
Important Notes
Tighten with suspension at ride height, or in similar position to prevent binding. Check for any binding in the rubber bushings.
2

Ball Joint Nut to Control Arm

M12 x 1.5
Torque Specification
41 ft-lbs (55 N·m)
Important Notes
This nut secures the ball joint to the control arm or steering knuckle. Ensure proper ball joint articulation after tightening.

Steering Linkage

1

Tie Rod End Nut to Steering Knuckle

M12 x 1.25
Torque Specification
37 ft-lbs (50 N·m)
Important Notes
Ensure the tie rod end is properly seated in the steering knuckle before tightening.

Sway Bar

1

Sway Bar Link Nut

M10 x 1.25
Torque Specification
37 ft-lbs (50 N·m)
Important Notes
This nut secures the sway bar link to the sway bar and the strut/control arm.
2

Sway Bar Mounting Bracket Bolts to Subframe/Body

M8 x 1.25
Torque Specification
24 ft-lbs (33 N·m)
Important Notes
Tighten evenly to prevent bracket distortion. Check for proper bushing seating after tightening.

Rear Subframe

1

Rear Subframe Mounting Bolts to Chassis

M14 x 1.5
Torque Specification
1. 81 ft-lbs (110 N·m) 2. 90°
Important Notes
These bolts are often torque-to-yield (stretch bolts) and should be replaced after removal. Tighten in sequence as specified in the vehicle's service manual.

Rear Control Arms

1

Rear Lower Control Arm to Hub Carrier (Knuckle) Bolts

M14 x 1.5
Torque Specification
74 ft-lbs (100 N·m)
Important Notes
Ensure the control arm is correctly aligned before final tightening. Check for any binding in the rubber bushings.
2

Rear Upper Control Arm to Hub Carrier (Knuckle) Bolts

M14 x 1.5
Torque Specification
74 ft-lbs (100 N·m)
Important Notes
Ensure the control arm is correctly aligned before final tightening. Check for any binding in the rubber bushings.

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 torque for the cylinder head bolts on a 2012-2018 BMW 340i?

According to BMW technical specifications, the cylinder head bolts should be tightened to 100 Nm (74 lb-ft) in a three-step sequence: 40 Nm (30 lb-ft), 60 Nm (44 lb-ft), and finally 100 Nm (74 lb-ft) using a calibrated torque wrench.

Q2

What IS the proper torque for the spark plugs on a BMW 340i (2012-2018)?

The spark plugs should be torqued to 25 Nm (18 lb-ft) using a torque wrench to ensure proper compression and seal. Overtightening can damage the spark plug threads or the cylinder head.

Q3

What type of torque wrench IS recommended for tightening critical bolts on a BMW 340i?

A high-quality, calibrated torque wrench with an adjustable torque range IS essential for accurate torque application. Refer to BMW workshop manuals for specific torque wrench requirements for various components.

Q4

How do I properly measure and apply torque using a torque wrench?

1. Set the torque wrench to the desired torque value. 2. Position the wrench perpendicular to the bolt and engage the socket. 3. Apply smooth, steady force until you hear or feel the wrench 'click,' indicating it has reached the set torque value. 4. If using a digital torque wrench, follow the manufacturer's instructions for reading and resetting the measurement.

Q5

What are the potential consequences of under- or over-tightening bolts on a BMW 340i?

Under-tightening bolts can lead to loose components, leaks, and potential failure. Over-tightening bolts can strip threads, damage components, and compromise structural integrity. Always adhere to the specified torque values and use a calibrated torque wrench.

Q6

Where can I find additional torque specifications for my BMW 340i?

Refer to the BMW repair manual for your specific model year. Additionally, consult with a certified BMW mechanic for professional guidance and access to the most up-to-date torque specifications.

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 340i.

  • 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 Sequence and Torque Specifications

Properly tightening cylinder head bolts IS critical for engine integrity. This procedure provides detailed instructions for the 340i's N55 engine.

  • Clean all bolt threads and mating surfaces
  • Apply engine oil to bolt threads
  • Tighten bolts in three stages: 30 Nm, 60 Nm, and 90 Nm
  • Follow the correct tightening sequence as specified in the BMW workshop manual
View full procedure

Wheel Lug Bolt Tightening Torque

Ensure proper wheel mounting by tightening lug bolts to the specified torque. This procedure covers both original and aftermarket wheels.

  • Clean all lug bolt threads and mating surfaces
  • Tighten bolts in a star pattern to 140 Nm
  • Recheck torque after 50 km of driving
View full procedure
Technical Service Bulletins

Technical Service Bulletin: Suspension Bolt Torque Specifications

2015-03-01

Updated torque specifications for certain suspension bolts to address a potential issue with premature wear and noise.

2013-2015 340i

Resolution: Replace affected bolts and tighten to the following specifications: - Control arm bolts: 125 Nm - Sway bar end link bolts: 65 Nm

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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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