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BMW DIY Ignition Coils N51, N52, N54, N55 6-cylinder – How to Remove and Replace

September 13, 2012

This “How-To” DIY post will address the late model “N” BMW 6-cylinder engines and removing the ignition coils in order to access the spark plugs.

Since the early 1990s, BMW has been using “direct ignition” or “coil-on-plug” ignition systems on most of their engines.  In order to access the spark plugs for service, the coils must first be removed.  Additionally, these coils do have occasional failures and need to be replaced.  Removal of the coils and access to the spark plugs is generally similar for all of these applications.  However, there are two basic differences in the coil designs.  The early versions are secured in place (on the valve cover) using two studs with nuts, on each coil (bolt-on style).  Later versions do not have the securing studs and nuts and simply push into place (pencil style).  Additionally, the harness plug connections are different between the two designs.  Note that we have produced a DIY How-To video that specifically addresses some important installation points on the harness plugs for the pencil coils.  See the video link below.

Removing the ignition coils on the newer N51 and N52 (as well as the N54 and N55) 6-cylinder engines is very similar to the prior generation M54 and S54 engines that also use the later “pencil” coils.  These coils do not have securing nuts or bolts as the earlier direct ignition engines do (M50, M52, M52TU, M54, S50, S52).  Once the coils are accessed, you simply remove the wiring harness plug and pull the coils out.

In this general DIY, we will show a sample photo DIY on removing the coils on an N51 6-cylinder, and replacement with our Bavarain Autosport High Performance Coils.  The N52 6-cylinder and the turbocharged N54 and N55 6-cylinders will be similar, but the valve cover trim removal will vary depending on the exact models.  The Bentley repair manuals will cover the specific procedures for a given BMW model.

Please see our additional DIY videos on coil replacement, to go along with this photo DIY.

Click HERE for links to our DIY videos on replacing “bolt-on” and “pencil” coils.

 Click below for Bentley repair manuals:

Click below for coils and spark plugs:

Procedure for N51 “pencil” coil replacement on 2007 328xi:

1)  Remove the cowl micro-filter and air inlet tray.

Remove the micro-filter cover by first removing the six 10mm hex-head bolts.

2)  Remove the driver side brake fluid reservoir cover and the corresponding passenger side cover by releasing the snap tabs.

3)  Release the clips securing the cable harness to the front of the cowl tray by inserting a screwdriver at the top of the clips to release the locking tabs.

4)  Remove the 10mm hex-head bolts securing the cowl tray and lift the tray out.

5)  Remove the four Torx-head bolts securing the valve cover trim panel.

6)  Remove the oil fill cap and lift the cover off.

7)  Pry the securing clips up and unplug the harness plugs from the coils (see the “pencil” coil video for more detail on this step).

8)  Pull the coils out (see “pencil” coil video for details).

9)  Install the new coils and install the harness plugs.  NOTE:  See the “pencil” coil DIY video for important notes and details on proper installation of the coil harness plugs.

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