August 22, 2023

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Spark Plug Replacement – BMW N20 Turbo 4-Cylinder Engine

This repair procedure gives step by step instructions on installing new spark plugs in the BMW N20 turbocharged 4-cylinder engine. We recommend the spark plugs be replaced in the N20 engine every 60,000 miles to keep it running at peak performance. Please click on the button below to see all BMW models that this repair applies to.

Not sure which engine you have in your BMW? Use our engine finder tool to easily identify it!

Possible Symptoms: Rough idle, poor performance, engine stalls

This repair can be used on the following BMW models:

2009

X1 20i SUV, X1 28i SUV, X1 28iX SUV,

2010

125i 3 doors, 125i 5 doors, 520i Sedan, 520i Touring, 528i Sedan, 528i Touring, 528iX Sedan, 528iX Touring, X1 20i SUV, X1 20iX SUV, X1 28i SUV, X1 28iX SUV,

2011

125i 3 doors, 125i 5 doors, 320Li Sedan, 320i Sedan, 320i Touring, 320iX Sedan, 328Li Sedan, 328i Sedan, 328iX Sedan, 328iX Touring, 520Li Sedan, 520i Sedan, 520i Touring, 525Li Sedan, 528i Sedan, 528i Touring, 528iX Sedan, 528iX Touring, X1 20i SUV, X1 20iX SUV, X1 28i SUV, X1 28iX SUV, X3 20iX SUV, X3 28iX SUV, Z4 20i Roadster, Z4 28i Roadster,

2012

125i 3 doors, 125i 5 doors, 220i Coupe, 228i Coupe, 320Li Sedan, 320i Gran Turismo, 320i Sedan, 320i Touring, 320iX Gran Turismo, 320iX Sedan, 320iX Touring, 328Li Sedan, 328i Gran Turismo, 328i Sedan, 328i Touring, 328iX Sedan, 328iX Touring, 428i Coupe, 428iX Coupe, 520Li Sedan, 520i Sedan, 520i Touring, 525Li Sedan, 528i Gran Turismo, 528i Sedan, 528i Touring, 528iX Sedan, 528iX Touring, X1 16i SUV, X1 20i SUV, X1 20iX SUV, X1 28i SUV, X1 28iX SUV, X3 20iX SUV, X3 28iX SUV, Z4 18i Roadster, Z4 20i Roadster, Z4 28i Roadster,

2013

125i 3 doors, 125i 5 doors, 220i Coupe, 228i Coupe, 228iX Coupe, 320Li Sedan, 320i Gran Turismo, 320i Sedan, 320i Touring, 320iX Gran Turismo, 320iX Sedan, 320iX Touring, 328Li Sedan, 328LiX Sedan, 328i Gran Turismo, 328i Sedan, 328iX Gran Turismo, 328iX Sedan, 328iX Touring, 420i Convertible, 420i Coupe, 420iX Coupe, 428i Convertible, 428i Coupe, 428i Gran Coupe, 428iX Convertible, 428iX Coupe, 428iX Gran Coupe, 520Li Sedan, 520i Sedan, 520i Touring, 525Li Sedan, 528Li Sedan, 528LiX Sedan, 528i Gran Turismo, 528i Sedan, 528i Touring, 528iX Sedan, 528iX Touring, 530Le Sedan, X1 16i SUV, X1 18i SUV, X1 20i SUV, X1 20iX SUV, X1 28i SUV, X1 28iX SUV, X3 18i SUV, X3 20i SUV, X3 20iX SUV, X3 28i SUV, X3 28iX SUV, X4 20iX SAC, X4 28iX SAC, X5 40eX SUV, Z4 18i Roadster, Z4 20i Roadster, Z4 28i Roadster,

2014

125i 3 doors, 125i 5 doors, 220i Convertible, 220i Coupe, 228i Convertible, 228i Coupe, 228iX Convertible, 228iX Coupe, 320Li Sedan, 320i Gran Turismo, 320i Sedan, 320i Touring, 320iX Gran Turismo, 320iX Sedan, 320iX Touring, 328Li Sedan, 328LiX Sedan, 328i Sedan, 328iX Gran Turismo, 328iX Sedan, 328iX Touring, 420i Convertible, 420i Coupe, 420iX Coupe, 428i Convertible, 428i Coupe, 428i Gran Coupe, 428iX Convertible, 428iX Coupe, 428iX Gran Coupe, 520Li Sedan, 520i Sedan, 520i Touring, 525Li Sedan, 528Li Sedan, 528LiX Sedan, 528i Gran Turismo, 528i Sedan, 528i Touring, 528iX Sedan, 528iX Touring, 530Le Sedan, X1 16i SUV, X1 18i SUV, X1 20i SUV, X1 20iX SUV, X1 28i SUV, X1 28iX SUV, X3 18i SUV, X3 20i SUV, X3 20iX SUV, X3 28i SUV, X3 28iX SUV, X4 20iX SAC, X4 28iX SAC, X5 28iX SUV, X5 40eX SUV, X6 28iX SAC, Z4 18i Roadster, Z4 20i Roadster, Z4 28i Roadster,

2015

2016

125i 3 doors, 125i 5 doors, 220i Convertible, 220i Coupe, 228i Coupe, 320Li Sedan, 320i Gran Turismo, 320i Sedan, 320iX Gran Turismo, 320iX Sedan, 328Li Sedan, 328LiX Sedan, 328i Sedan, 328iX Touring, 420i Convertible, 420i Coupe, 420iX Coupe, 428i Coupe, 520Li Sedan, 520i Sedan, 520i Touring, 525Li Sedan, 528Li Sedan, 528LiX Sedan, 528i Gran Turismo, 528i Sedan, 528i Touring, 528iX Sedan, 528iX Touring, 530Le Sedan, X3 18i SUV, X3 20i SUV, X3 20iX SUV, X3 28i SUV, X3 28iX SUV, X4 20iX SAC, X4 28iX SAC, X5 28iX SUV, X5 40eX SUV, X6 28iX SAC, Z4 18i Roadster, Z4 20i Roadster, Z4 28i Roadster,

2017

320i Sedan, 320iX Sedan, 520Li Sedan, 520i Touring, 525Li Sedan, 528i Gran Turismo, 528i Touring, 528iX Touring, X3 18i SUV, X3 20i SUV, X3 20iX SUV, X3 28i SUV, X3 28iX SUV, X4 20iX SAC, X4 28iX SAC, X5 28iX SUV, X5 40eX SUV, X6 28iX SAC,

2018

320i Sedan, 320iX Sedan, X4 20iX SAC, X4 28iX SAC, X5 28iX SUV, X5 40eX SUV, X6 28iX SAC,

2019

X6 28iX SAC,

Advanced level repair.

Step 1 - Purchase Parts

You will need the following parts and supplies to perform this repair.

Spark Plug

Don't be fooled by aftermarket manufacturers that claim their plugs are "OEM". There is only one trusted source for factory spark plugs...Genuine BMW. These are the same factory plugs that would be installed at the dealership.

14mm Spark Plug Tool with Magnetic Swivel

Removing spark plugs with a rigid, none-magnetic socket wrench is not only tedious but can actually cause damage to your vehicle's engine. This socket wrench holds on firmly to the spark plug with its super strong magnetic tip. Its 360 degree of swivel makes it easy to remove spark plugs buried under parts or located close to the firewall in the rear of the engine. A necessity for every professional and home mechanic.

Spark Plug Installation Tool

Professional mechanics know that only a darn fool drops a spark plug into a cylinder head tube when installing a new one. Dropping a plug down its tube can cause the plug gap to be bent causing a rough idling engine. This rubber spark plug installation tool safely threads the new plug into the head. Using this tool is cheap insurance against damaged plugs, cross threading and potential engine damage.

Step 2 - Repair Procedure

Unless otherwise noted, all vehicle repair step images in this article are copyrighted, and used courtesy of BMW of North America, Inc. .

You must remove the ignition coils before starting this repair!

Please see our article Ignition Coil Replacement – N20 Turbo 4-Cylinder Engine.

1. Removing and installing spark plugs.

Spark Plug Replacement – BMW N20 Turbo 4-Cylinder Engine

Click to enlarge image

- The best tool for removing spark plugs from the N20 engine is a 3/8" ratchet with an extension and magnetic spark plug socket. This will help avoid breaking the spark plug off inside the tube.

Click to enlarge image

- Using a 14mm magnetic swivel spark plug socket, remove spark plug 12120039664 from the cylinder head.

View part diagram for this step

Pro Tip

Avoid "dropping" the spark plug into the tube when reinstalling a fresh one. This can throw off the gap at the end of the plug causing your engine to run rough!

Click to enlarge image

- The best tool for installing a spark plug is a rubber spark plug installation tool. It helps avoid cross-threading the spark plug into the cylinder head and is much easier to use than a swivel head socket.

Click to enlarge image

- Install a new spark plug 12120039664. Torque the spark plug to 30 Nm (22 ft-lb).

View part diagram for this step

Replace the ignition coils.

Please see our article Ignition Coil Replacement - N20 Turbo 4-Cylinder Engine for instructions on replacing the ignition coils.