BMW Vehicle Models 340i 2019-present Torque Specifications
BMW Vehicle Models 340i 2019-present

BMW Vehicle Models 340i 2019-present Torque Specifications

Complete BMW Vehicle Models 340i 2019-present torque specifications guide. Includes factory-specified torque values, torque sequences, and technical specifications for all components including body, brakes, drivetrain, electrical, emissions sensors, fuel, exhaust, HVAC, and suspension. Essential information for proper assembly and maintenance.

Updated

Important Information

Safety guidelines and reference information for proper torque application

Quick Reference Guide
ft-lbs → Nm
× 1.356
ft-lbs → kg-m
× 0.138
Nm → ft-lbs
× 0.738
in-lbs → ft-lbs
× 0.083

Common Torque Patterns

Star Pattern

Used for wheels and other circular bolt patterns

Star Pattern torque pattern diagram showing proper bolt tightening sequence
Cross Pattern

Used for gaskets and cover plates

Cross Pattern torque pattern diagram showing proper bolt tightening sequence
Sequential Pattern

Used for head bolts and other critical components

Sequential Pattern torque pattern diagram showing proper bolt tightening sequence

Common Mistakes to Avoid

Over-tightening

Exceeding the specified torque value can stretch or break fasteners, damage threads, or crack components.

Prevention:

Always use a calibrated torque wrench and follow specifications exactly.

Incorrect Torque Sequence

Tightening bolts in the wrong order can cause uneven pressure distribution and potential leaks or damage.

Prevention:

Follow the manufacturer's specified torque sequence pattern.

Dirty Threads

Dirt, rust, or old thread locker can affect torque readings and proper fastener tension.

Prevention:

Clean and inspect all threads before assembly. Use new thread locker if specified.

Reusing TTY Bolts

Torque-to-yield bolts are designed to stretch and must not be reused.

Prevention:

Always replace TTY bolts with new ones. They are single-use only.

Dry vs. Lubricated

Not accounting for whether torque specs are for dry or lubricated fasteners can lead to incorrect tension.

Prevention:

Check if specs are for dry or lubricated threads. Use specified lubricant when required.

Recommended Tools

Torque Wrench (1/4" Drive)

Range: 2-25 ft-lbs
Small fasteners, delicate components

Torque Wrench (3/8" Drive)

Range: 10-100 ft-lbs
Most common automotive fasteners

Torque Wrench (1/2" Drive)

Range: 30-250 ft-lbs
Large fasteners, wheels

Angle Gauge

Torque-to-yield (TTY) bolts

Torque Wrench Care

  • Calibrate annually or after 5,000 clicks
  • Store at lowest setting
  • Keep clean and lubricated

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Torque Calculator

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3.0l Engine

Torque specifications for 3.0L Engine

Cylinder Head

1

Cylinder Head Bolts

M12 x 1.5
Torque Specification
1. 20 ft-lbs (27 N·m)
Important Notes
Tighten in a specific sequence, usually starting from the center and moving outwards. Refer to service manual for specific pattern.
2

Camshaft Bearing Cap Bolts

M8 x 1.25
Torque Specification
1. 8 ft-lbs (11 N·m) 2. 90°
Important Notes
These bolts require a torque-plus-angle tightening procedure. These are likely stretch bolts and must be replaced if removed.
3

Rocker Arms/Shafts Bolts

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

Variable Valve Timing (VVT) Solenoid Bolts

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

Vanos Unit Bolts

M8 x 1.25
Torque Specification
1. 8 ft-lbs (11 N·m) 2. 45°
Important Notes
These bolts require a torque-plus-angle tightening procedure. These are likely stretch bolts and must be replaced if removed.

Engine Block

1

Main Bearing Bolts

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

Connecting Rod Nuts

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

Oil Pan Bolts

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

Oil Filter Housing Bolt

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

Oil Drain Plug Bolt

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

Knock Sensor Bolts

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

Intake System

1

Intake Manifold Bolts

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

Throttle Body Bolts

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

Fuel Rail Bolts

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

Fuel Injector Bolts

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

EGR Valve Bolts

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

Exhaust System

1

Exhaust Manifold/Headers to Cylinder Head Bolts

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

Cooling System

1

Water Pump Bolts

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

Water Pump Pulley Bolts

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

Thermostat Housing Bolts

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

Front End Accessory Drive

1

Serpentine/Accessory Drive Belt Tensioner Bolt

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

Drive Belt Idler Pulley Bolt

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

Crankshaft Pulley/Harmonic Balancer Bolt

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

Valve Train

1

Timing Belt/Chain Tensioner Bolt

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

Camshaft Sprocket Bolt

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

Ignition System

1

Spark Plugs

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

Ignition Coil Bolts

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

8hp Transmission

Torque specifications for 8hp Transmission

Transmission Mounting

1

Transmission Mounting Bolts

M12 x 1.5
Torque Specification
50 ft-lbs (68 N·m)
Important Notes
Ensure proper alignment of transmission before tightening. Use new bolts if specified by the manufacturer.

Transmission Oil Pan

1

Transmission Oil Pan Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Tighten bolts in a criss-cross pattern to evenly compress the gasket and ensure proper sealing. Always use a new gasket.

Drain And Fill Plugs

1

Transmission Drain and Fill Plugs

M18 x 1.5
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Always use a new crush washer to ensure a proper seal. Avoid over-tightening.

Mechatronics Unit

1

Mechatronics Unit Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (10 N·m)
Important Notes
Use a torque wrench with a low range setting and tighten in a specific sequence to avoid warping or damaging the mechatronics unit. Refer to repair manual for exact sequence. Always use a new seal.

Bell Housing

1

Transmission Bell Housing Bolts

M12 x 1.75
Torque Specification
40 ft-lbs (55 N·m)
Important Notes
Ensure proper alignment of the transmission and engine before tightening. Use new bolts if specified by the manufacturer. Tighten in a criss-cross pattern.

Cooler Line Fittings

1

Transmission Cooler Line Fittings

M16 x 1.5 (estimated)
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Use two wrenches, one to hold the fitting on the transmission case and another to tighten the line nut. Always use new sealing washers.

Torque Converter

1

Torque Converter Bolts

M10 x 1.5
Torque Specification
35 ft-lbs (47 N·m)
Important Notes
Tighten bolts evenly in a star pattern to avoid stress on the flex plate. Always use new bolts if specified by the manufacturer.

Output Flange

1

Transmission Output Flange/Yoke Bolts

M10 x 1.5
Torque Specification
40 ft-lbs (55 N·m)
Important Notes
Ensure proper alignment of the flange and driveshaft. Use new bolts if specified by the manufacturer. Tighten evenly.

Body

Torque specifications for Body

Wheels And Tires

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. Verify torque after 50-100 miles of driving.

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 aligned before tightening. Do not overtighten.
2

Fuel Filler Neck Bolts

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

Doors

1

Door Hinge Bolts (Body Side)

M8 x 1.25
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
Ensure door is properly aligned before tightening. Partially tighten bolts before final torque. Estimated value.
2

Door Latch Striker Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure proper latch engagement. Partially tighten all bolts before final torque. Estimated Value.

Hood

1

Hood Hinge Bolts (Body Side)

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

Fenders

1

Fender Bolts (Inner)

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Do not overtighten, these bolts often go into plastic clips. Estimated Value.
2

Fender Bolts (Outer)

M8 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Ensure fender alignment before tightening. Partially tighten all bolts before final torque. Estimated value.

Bumpers

1

Bumper Cover Mounting Bolts/Nuts (Smaller)

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Smaller bolts used for mounting bumper cover. Do not overtighten. Estimated value.
2

Bumper Cover Mounting Bolts/Nuts (Larger)

M8 x 1.25
Torque Specification
28 ft-lbs (38 N·m)
Important Notes
Larger bolts/nuts used for mounting bumper cover. Ensure alignment. Estimated value.

Lighting

1

Headlight Mounting Bolts

M6 x 1.0
Torque Specification
9 ft-lbs (12 N·m)
Important Notes
Do not overtighten. Ensure proper headlight alignment. Estimated value.
2

Taillight Mounting Bolts

M6 x 1.0
Torque Specification
9 ft-lbs (12 N·m)
Important Notes
Do not overtighten. Ensure proper taillight alignment. Estimated value.

Grille

1

Grille Mounting Bolts/Screws

M5 x 0.8
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Do not overtighten. Ensure proper grille alignment. Estimated value.

Side Skirts

1

Side Skirt/Rocker Panel Mounting Bolts/Screws

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

Windshield Cowl

1

Windshield Cowl Bolts

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

Rear Hatch Trunk

1

Rear Hatch/Trunk Lid Hinge Bolts (Body Side)

M8 x 1.25
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
Ensure hatch/trunk lid is properly aligned before tightening. Partially tighten bolts before final torque. Estimated value.
2

Rear Hatch/Trunk Lid Latch Striker Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure proper latch engagement. Partially tighten all bolts before final torque. Estimated Value.

Brakes

Torque specifications for Brakes

Caliper Mounting

1

Caliper Mounting Bolts

M12 x 1.5
Torque Specification
80 ft-lbs (108 N·m)
Important Notes
Ensure bolts are clean and threads are in good condition. Apply a thin coat of anti-seize to the bolt threads. Tighten evenly.
2

Caliper Mounting Bracket Bolts

M14 x 1.5
Torque Specification
100 ft-lbs (136 N·m)
Important Notes
Ensure the bracket is seated flush against the hub. Bolts must be free of damage and debris. Apply a thin coat of anti-seize to the threads.

Rotor Mounting

1

Rotor Retaining Bolt

M8 x 1.25
Torque Specification
12 ft-lbs (16 N·m)
Important Notes
This bolt is primarily for retaining the rotor during wheel installation and may not be present on all vehicles. Ensure the rotor is seated flush on the hub.

Pad Hardware

1

Brake Pad Retaining Pin/Bolt

M6 x 1.0
Torque Specification
12 ft-lbs (16 N·m)
Important Notes
Ensure pins are clean and in good condition. Do not overtighten.
2

Anti-Rattle Clip Bolt

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensure the anti-rattle clips are properly positioned. Do not overtighten.

Hydraulic System

1

Brake Caliper Bleeder Screw

M10 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Overtightening may damage the screw or the caliper. Use a wrench that fits the bleeder screw correctly.
2

Brake Line Fitting (Banjo Bolt)

M10 x 1.0
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Use new crush washers when installing banjo fittings. Ensure lines are properly aligned before tightening. Do not overtighten to avoid leaks.
3

Brake Line Fitting (Hardline)

M10 x 1.0
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure lines are properly aligned before tightening. Use a flare wrench to avoid rounding the fitting. Do not overtighten to avoid leaks.

Hose Brackets

1

Brake Hose Bracket Mounting Bolt

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensure the bracket aligns correctly and there is no pinching of the brake hose. Do not overtighten.

Drivetrain

Torque specifications for Drivetrain

Engine To Transmission

1

Flywheel Bolts (Manual Transmission)

M12 x 1.5
Torque Specification
55 ft-lbs (75 N·m)
Important Notes
Ensure flywheel is properly aligned before tightening. Use new bolts if recommended by the service manual.
2

Flex Plate Bolts (Automatic Transmission)

M10 x 1.25
Torque Specification
1. 45 ft-lbs (61 N·m) 2. 90°
Important Notes
Tighten to the specified torque, then by an additional 90 degrees. Use new bolts.
3

Transmission Mounting Bolts

M12 x 1.75
Torque Specification
50 ft-lbs (68 N·m)
Important Notes
Ensure the transmission is properly aligned and supported before tightening.
4

Torque Converter Bolts

M10 x 1.5
Torque Specification
35 ft-lbs (47 N·m)
Important Notes
Ensure torque converter is fully seated to the flex plate. Use new bolts when possible.

Transmission

1

Transmission Oil Pan Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Tighten in a cross pattern to avoid warping the pan.
2

Transmission Drain and Fill Plugs

M18 x 1.5
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Use new crush washers if recommended by the manual. Do not over-tighten to avoid damaging the threads.
3

Output Flange/Companion Flange Bolts

M10 x 1.5
Torque Specification
50 ft-lbs (68 N·m)
Important Notes
These bolts secure the output flanges to the transmission where the driveshaft or axles bolt onto. Proper torque is necessary to prevent vibration and ensure joint integrity.

Drive Shaft

1

Propeller/Drive Shaft Bolts

M10 x 1.5
Torque Specification
60 ft-lbs (81 N·m)
Important Notes
Ensure correct orientation of driveshaft to prevent vibration.

Rear Axle

1

Drive Axle/Half Shaft Bolts

M10 x 1.5
Torque Specification
85 ft-lbs (115 N·m)
Important Notes
Ensure proper seating of the axle before tightening.
2

CV Joint/Axle Nut

M24 x 1.5
Torque Specification
185 ft-lbs (251 N·m)
Important Notes
Use a new nut if recommended by the service manual. Proper torque is crucial for wheel bearing preload.
3

Differential Mounting Bolts/Nuts

M14 x 2.0
Torque Specification
60 ft-lbs (81 N·m)
Important Notes
Torque values may vary by location, consult service manual. Ensure proper differential alignment.
4

Differential Drain/Fill Plug

M16 x 1.5
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Use a new crush washer if recommended by the manual.
5

Output Flange/Companion Flange Bolts (Differential)

M10 x 1.5
Torque Specification
50 ft-lbs (68 N·m)
Important Notes
These bolts secure the output flange to the differential, ensure the flange is correctly aligned.

Transfer Case

1

Transfer Case Drain/Fill Plug

M16 x 1.5
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Use a new crush washer if recommended by the manual.

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 contact and grounding. Over-tightening can damage coil or valve cover.

Starting System

1

Starter Motor Mounting Bolts

M10 x 1.5
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Securely mounts the starter to the engine block and ensures proper grounding. Estimated value.

Charging System

1

Alternator Mounting Bolts

M10 x 1.5
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Ensures proper alignment, belt tension, and grounding. Estimated Value.

Battery System

1

Battery Terminal Nuts

M8 x 1.25
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensures reliable electrical contact without damaging the battery terminals. Over tightening can damage the battery post.

Grounding System

1

Ground Strap/Wire Mounting Bolt (Chassis)

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensures a secure ground connection. Check for corrosion before install. Estimated value.
2

Ground Strap/Wire Mounting Bolt (Engine)

M8 x 1.25
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Ensures a secure ground connection. Check for corrosion before install. Estimated value.

Engine Control Unit

1

ECU/DME Mounting Bolts

M5 x 0.8
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Low torque to avoid damage to the ECU housing.

Sensors

1

Crankshaft Position Sensor Mounting Bolt

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Low torque to prevent sensor damage. Estimated value.
2

Camshaft Position Sensor Mounting Bolt

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Low torque to prevent sensor damage. Estimated value.
3

Mass Air Flow (MAF) Sensor Mounting Bolts

M5 x 0.8
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Low torque to prevent damage to the sensor or housing. Estimated value.

Fuse Relay Boxes

1

Fuse/Relay Box Mounting Bolts/Screws

M4 x 0.7
Torque Specification
5 ft-lbs (7 N·m)
Important Notes
Low torque for plastic enclosures. Over tightening can break plastic or screws. Estimated value.

Emissions Sensors

Torque specifications for Emissions_sensors

Exhaust Manifold

1

Exhaust Manifold to Cylinder Head Bolts

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Ensure proper torque sequence as specified in the service manual. Tighten bolts in a cross pattern to ensure even pressure distribution.
2

Exhaust Pipe to Exhaust Manifold/Header Bolts

M10 x 1.5
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Ensure proper gasket is used. Tighten bolts in an alternating sequence.
3

Exhaust Manifold/Headers Mounting Bolts

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Ensure proper gasket is used. Tighten bolts in an alternating sequence.

Catalytic Converter

1

Catalytic Converter to Exhaust Pipe Bolts

M10 x 1.5
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Use new gaskets. Tighten bolts in an alternating sequence to ensure even pressure.

Oxygen Sensors

1

O2 Sensor (into exhaust manifold or pipe)

M18 x 1.5
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Apply anti-seize compound to sensor threads (if specified by manufacturer). Ensure sensor is properly seated before tightening. This value is an estimate, always confirm with the specific sensor manufacturer's instructions.

Nox Sensors

1

NOx Sensor (into exhaust pipe/catalytic converter)

M20 x 1.5
Torque Specification
37 ft-lbs (50 N·m)
Important Notes
Apply anti-seize compound to sensor threads (if specified by manufacturer). Ensure sensor is properly seated before tightening. This value is an estimate, always confirm with the specific sensor manufacturer's instructions.

Egt Sensors

1

EGT Sensor (into exhaust manifold/pipe)

M14 x 1.25
Torque Specification
15 ft-lbs (20 N·m)
Important Notes
Apply anti-seize compound to sensor threads (if specified by manufacturer). Ensure sensor is properly seated before tightening. This value is an estimate, always confirm with the specific sensor manufacturer's instructions.

Egr System

1

EGR Valve Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Use new gasket, ensure proper alignment. Tighten bolts evenly to avoid warping the valve.

Fuel System

1

Fuel Injector Rail Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
Tighten bolts evenly to prevent fuel leaks. Ensure all o-rings are in place prior to tightening

Intake System

1

MAF (Mass Air Flow) Sensor Mounting Bolts

M5 x 0.8
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Ensure proper o-ring/seal is in place. Do not overtighten to prevent damage to the sensor housing.

Differential Pressure Sensor

1

Differential Pressure Sensor Mounting Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (9.5 N·m)
Important Notes
Do not overtighten, as this can damage the sensor. This is an estimated value, always check the service manual.

Exhaust

Torque specifications for Exhaust

Exhaust Manifold

1

Exhaust Manifold to Cylinder Head Bolts

M8 x 1.25
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Ensure mating surfaces are clean and free of debris. Apply anti-seize to bolt threads to prevent corrosion.

Exhaust Piping

1

Exhaust Pipe to Exhaust Manifold/Header Bolts

M10 x 1.5
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Ensure the flange is properly aligned. A new gasket or sealant may be required.
2

Catalytic Converter to Exhaust Pipe Bolts

M10 x 1.5
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Use new gaskets or sealant if necessary. Check for proper alignment of the flanges.
3

Muffler to Exhaust Pipe Bolts

M10 x 1.5
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
Ensure proper alignment to prevent stress on the exhaust system. Use new gaskets or sealant.

Exhaust Hangers

1

Exhaust Hanger Bolts/Nuts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Do not overtighten, as this may cause deformation. Use proper sized washers.

Exhaust Flanges

1

Small Exhaust Flange Bolts

M8 x 1.25
Torque Specification
18 ft-lbs (24 N·m)
Important Notes
Ensure a proper fit and a good seal. Always use a new gasket if possible.
2

Medium Exhaust Flange Bolts

M10 x 1.5
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Ensure a proper fit and a good seal. Always use a new gasket if possible.
3

Large Exhaust Flange Bolts

M12 x 1.75
Torque Specification
40 ft-lbs (54 N·m)
Important Notes
Ensure a proper fit and a good seal. Always use a new gasket if possible.

Fuel

Torque specifications for Fuel

Fuel Rail

1

Fuel Rail Mounting Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
These bolts secure the fuel rail to the intake manifold or cylinder head. Ensure proper torque to prevent fuel leaks and damage.
2

Fuel Injector Mounting Bolts

M5 x 0.8
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
These bolts secure the fuel injectors to the fuel rail or intake manifold. Use care, as these are sometimes small Torx head bolts and can be easily damaged.
3

Fuel Pressure Sensor Bolts

M5 x 0.8
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
These bolts secure the fuel pressure sensor to the fuel rail or fuel lines. Due to the sensitive nature of the sensor, lower torque is required. Estimated value.

Fuel Pump

1

Fuel Pump Mounting Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
These bolts secure the fuel pump assembly to the fuel tank. Ensure correct torque to maintain a secure and leak-free connection.
2

Fuel Tank Sending Unit/Fuel Pump Module Lock Ring

N/A
Torque Specification
52 ft-lbs (70 N·m)
Important Notes
This lock ring holds down the pump assembly in the tank. Ensure proper torque to avoid leaks or damage to the ring. Estimated value. Use a specialized tool for this.
3

Fuel Tank Drain Plug (if applicable)

M14 x 1.5
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
If equipped, this plug needs to be properly torqued to prevent fuel leaks from the tank. Estimated value.

Fuel Lines

1

High Pressure Fuel Line Fitting (M12)

M12 x 1.5
Torque Specification
20 ft-lbs (27 N·m)
Important Notes
High-pressure fuel line fittings require precise torque. Over-torquing can damage the fitting or line. Under-torquing may lead to leaks. Estimated value.
2

Fuel Filter Bolt/Nut

M8 x 1.25
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
These secure the fuel filter assembly to the vehicle body or bracket. Proper torque prevents leaks around the mounting points.
3

Fuel Line Bracket Bolts

M6 x 1.0
Torque Specification
7 ft-lbs (9.5 N·m)
Important Notes
These bolts secure the fuel lines to the chassis. Ensure correct torque to prevent fuel lines from rubbing against vehicle parts. Estimated value.

Fuel Filler

1

Fuel Filler Neck Bolts

M6 x 1.0
Torque Specification
10 ft-lbs (14 N·m)
Important Notes
These bolts attach the fuel filler neck to the vehicle body. Proper torque ensures a tight seal to prevent vapor leaks.

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 bolts are clean and lightly lubricated with engine oil before installation. Over-tightening may lead to bolt failure and compressor damage. Use a torque wrench.

Ac Lines

1

A/C Line Fittings

Varies (M10 x 1.25, M12 x 1.5 typical)
Torque Specification
25 ft-lbs (34 N·m)
Important Notes
Ensure O-rings are properly seated and lightly lubricated with refrigerant oil before assembly. Over-tightening can damage fittings or O-rings and cause leaks, while under-tightening can also cause leaks. Use a flare nut wrench or crowsfoot adapter when needed.

Ac Condenser

1

Condenser Mounting Bolts

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Use caution when tightening these bolts, as the condenser is often mounted to thin metal supports. Over-tightening can cause damage or distortion. This value is an estimate, confirm against service manual if possible.

Evaporator Housing

1

Evaporator Housing Bolts/Fasteners

M5 x 0.8
Torque Specification
6 ft-lbs (8 N·m)
Important Notes
The Evaporator housing often contains plastic fasteners or self-tapping screws; care must be taken to not over-tighten and strip the fasteners or plastic. These torque values are an estimate. Confirm against the service manual for your specific vehicle.

Blower Motor

1

Blower Motor Mounting Screws

M4 x 0.7
Torque Specification
4 ft-lbs (5.5 N·m)
Important Notes
Blower motor mounting screws are small and can easily be over-tightened. Use caution when tightening these fasteners. This torque value is an estimate, confirm with service manual for your specific application.

Expansion Valve

1

Expansion Valve Mounting Bolts

M6 x 1.0
Torque Specification
8 ft-lbs (11 N·m)
Important Notes
Over-tightening the expansion valve mounting bolts can cause leaks and damage the valve. Ensure O-rings or seals are correctly positioned before installation. This value is an estimate. Confirm with service manual if possible.

Suspension

Torque specifications for Suspension

Front Suspension

1

Strut/Shock Absorber Lower Mounting Bolts

M12 x 1.5
Torque Specification
30 ft-lbs (41 N·m)
Important Notes
Secures the strut to the steering knuckle. Use new bolts if specified by the service manual.
2

Strut Top Mount Nuts

M8 x 1.25
Torque Specification
22 ft-lbs (30 N·m)
Important Notes
Secures the top of the strut to the chassis. Tighten evenly to avoid damage to the mount. Estimated value.
3

Front Lower Control Arm Inner Bushing Bolts

M14 x 1.5
Torque Specification
1. 65 ft-lbs (88 N·m) 2. 90°
Important Notes
Secures the control arm to the subframe. Follow torque and angle sequence precisely. Estimated value.
4

Front Strut Pinch Bolt

M12 x 1.75
Torque Specification
45 ft-lbs (61 N·m)
Important Notes
Clamps the steering knuckle to the bottom of the strut. Use new bolts if specified by the service manual. Estimated value.
5

Ball Joint Nut

M14 x 1.5
Torque Specification
55 ft-lbs (75 N·m)
Important Notes
Secures the ball joint to the control arm or steering knuckle. Ensure the ball joint is properly seated.
6

Tie Rod End Nut

M12 x 1.25
Torque Specification
35 ft-lbs (47 N·m)
Important Notes
Secures the tie rod end to the steering knuckle. Ensure proper alignment before tightening.
7

Sway Bar Link Nut

M10 x 1.5
Torque Specification
35 ft-lbs (47 N·m)
Important Notes
Connects the sway bar to the strut or control arm. Tighten with the suspension loaded if specified.

Rear Suspension

1

Rear Subframe Bolts

M14 x 1.5
Torque Specification
1. 75 ft-lbs (102 N·m) 2. 90°
Important Notes
Secures the rear subframe to the chassis. This is a torque to yield bolt. Follow specific torque and angle sequence precisely. Always use new bolts. Estimated value.
2

Rear Trailing Arm Bolts

M12 x 1.5
Torque Specification
75 ft-lbs (102 N·m)
Important Notes
Attaches the trailing arm to the subframe. Ensure proper alignment before tightening. Estimated value.
3

Rear Upper Control Arm Bolts

M12 x 1.5
Torque Specification
65 ft-lbs (88 N·m)
Important Notes
Secures the upper control arm to the chassis or subframe. Estimated value.

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 proper torque specification for cylinder head bolts on the N55 engine?

Tighten the cylinder head bolts in three stages: 30 Nm (22 lb-ft), 60 Nm (44 lb-ft), and 90 Nm (66 lb-ft) + 90 degrees

Q2

What IS the torque specification for the oil filter housing cap?

25 Nm (18 lb-ft)

Q3

What are the torque specifications for the spark plugs?

20 Nm (15 lb-ft)

Q4

What torque wrench should I use for critical fasteners like the cylinder head bolts?

Use a calibrated torque wrench with a range of 0-150 Nm (0-110 lb-ft)

Q5

IS it safe to exceed the specified torque values?

No, exceeding the torque specifications can damage components or cause bolts to stretch and lose their clamping force

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

Engine Bolt Torque Specifications

Technical procedure for tightening engine bolts to specified torque values on a BMW 340i.

  • Locate the engine bolt to be tightened.
  • Clean the bolt and threads with a degreaser.
  • Apply a small amount of thread locker to the bolt threads.
  • Tighten the bolt to the specified torque using a digital torque wrench.
  • Double-check the torque value with a torque wrench.
View full procedure

Suspension Bolt Torque Specifications

Technical procedure for tightening suspension bolts to specified torque values on a BMW 340i.

  • Locate the suspension bolt to be tightened.
  • Clean the bolt and threads with a degreaser.
  • Apply a small amount of anti-seize compound to the bolt threads.
  • Tighten the bolt to the specified torque using a digital torque wrench.
  • Double-check the torque value with a torque wrench.
View full procedure
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.
  • Vehicle specifications and procedures may vary by model year, trim level, and region.
  • Always follow the manufacturer's recommended procedures and safety precautions.
  • Working on vehicles can be dangerous. Always take proper safety precautions and use appropriate safety equipment.
  • If you're unsure about any procedure, consult a qualified professional mechanic.
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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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