BMW DIY Ignition Coils N51, N52, N54, N55 6-cylinder – How to Remove and Replace
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.
Procedure for N51 “pencil” coil replacement on 2007 328xi:
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.