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BMW E90 E91 E92 E93 Valve Cover Gasket Replacement DIY N52N Engine

In this article I will show you how to replace a valve cover gasket on your E90, E91, E92 or E93 BMW 3-Series with N52N Engine.  This article can also be used as a guide for replacing the eccentric shaft sensor. The work was done on a 2007 328xi so procedure may vary slightly on other models but probably not by much. 

To do this job properly you will need a valve cover gasket set, eccentric shaft sensor seal, camshaft adjuster seal and spark plug tubes.  Some other parts you may want to consider purchasing are a cabin air filter and spark plugs.

1. Unplug the battery and start by removing the cabin air filter box.

BMW E90 Cabin Air Filter Removal

2.  Once the cabin air filter box is out of the way, remove the cowling by unscrewing the two screws.  There are some wires and sensors that are attached to the cowling so unclip them and lay them aside.

BMW E90 Removing the Cowling

3.  Remove the windshield wiper arms.

BMW E90 328xi Removing the windshield wiper arms

4.  Once the wiper arms are off you will need to remove the wiper motor cover, the cover that is right up against the windshield.  Start by pulling off the windshield washer hose.

BMW E90 328xi disconnecing the windshield washer hose

5.  The wiper motor cover clips on to the seal that goes under the windshield so you will need to carefully pry it up.  Once it is loose unclip the wiring connectors for the heated washer nozzles if your car is equipped with those.  Remove the wiper motor cover and lay it aside.

BMW E90 328xi disconnecting heated washer nozzles

6.  Once the wiper motor cover is out of the way remove the strut tower bracing.

BMW E90 328xi Removing Strut Braces

7.  Remove the 3 screws for the center of the trim that mounts to the firewall and remove the center section.

BMW E90 328xi Removing Firewall Trim

8.  Remove the two screws that hold the passenger side trim to the firewall, unclip the wiring and remove the trim.

BMW E90 328xi Removing Passenger Side Firewall Trim

9.  Remove the engine acoustic cover.

BMW E90 328xi Removing Engine Acoustic Cover

10.  Once the cover is off start disconnecting the electrical connectors.  Disconnect the ignition coils, the eccentric shaft sensor, valvetronic motor, ground straps for the ignition coil harness, O2 sensor connectors, oil pressure switch, camshaft position sensor and the fuel injector harness.  Fuel injector harness unplugs by pulling up on it.  It will take some force so try to pull up on it as evenly as possible to avoid damage.

BMW E90 328xi Disconnecting Ignition Coil Harness

11.  Move the entire wiring harness over to the passenger side of the car.  You can use some zip ties to keep the wiring in place and out of the way.  Unclip the coolant expansion tank breather hose.  You will have some coolant drip out of the hose so have a rag ready to catch the spilling coolant.

BMW E90 328xi Moving aside wiring harness

12.  Unclip the breather hose at the back of the valve cover.  This hose tends to get brittle with time so you might want to order a new one just in case.  You can always return it back to us if you end up not using it.

BMW E90 328xi Disconnecting Engine Breather Hose

13.  Pull out the ignition coils.  You'll have to wiggle them a bit side to side first to get them going.  Be careful not to break the connector clip.

BMW E90 328xi Removing Ignition Coils

14.  Remove the camshaft adjuster motor by removing the three screws.  It will just push out once the screws are loose.  There is also a hole in the back where you can insert a hex bit and screw it out but in most cases it isn't necessary. 

BMW E90 328xi Removing Camshaft Adjuster

15.  Using a screwdriver and needle-nose pliers pull out the spark plug tubes and discard.   This is also a perfect time to replace the spark plugs if it hasn't been done in a while.

BMW E90 328xi Removing Spark Plug Tubes

16.  Loosen all of the screws that hold the valve cover to the cylinder head.  Do so in steps going from the outside towards the center.  Note the type of screw used in each location.  Some screws are different because there are dowels in the cylinder head.

Remove the plastic covering from the wiring harness.  Removing it will give you more clearance when removing the valve cover.

BMW E90 328xi Removing Valve Cover

17.  Remove the plastic cover from the ECU box and pull the wires up slightly to allow more clearance for the valve cover removal.

BMW E90 328xi Removing ECU Box Cover

18.  Remove the valve cover and clean all of the gasket contact surfaces.  

BMW E90 328xi Valve Cover Removed

19.  Clean the valve cover and inspect it.  Make sure it is flat and free of damage and cracks.  Install a new eccentric shaft sensor seal driving it in with a large socket.  Use some fresh oil on the seal when driving it in to avoid damage.  Also install a new camshaft adjuster seal.

BMW E90 328xi Installing Eccentric Shaft Sensor Seal

20.  Place the valve cover with a new gasket back on the cylinder head.  When performing this step it is nice to have a helper who will hold the wires up as high as possible for you.  After placing the valve cover back on the engine inspect the gasket.  Go all the way around with an inspection mirror and a flashlight to make sure the gasket is seated properly.  Torque the valve cover bolts back to specs starting from the center and going out in a circular pattern.

BMW E90 328xi Installing Valve Cover

21.  Reinstall the camshaft adjuster.  You shouldn't have to do anything special to reinstall it.  Just push it in and torque it down.

BMW E90 328xi Installing Camshaft Adjuster

22.  Insert new sparkplug tubes into the sparkplug holes and tap them in using an appropriate sized socket.

BMW E90 328xi Installing Spark Plug Tubes

23.  That is about it.  Reinstall the rest in the reverse order.  Camshaft adjuster unit can be realigned by using BMW diagnostic software but it should not be necessary.  Once you start the car it will adjust itself.   If you are doing this for the first time plan on spending at least 5 hours on the job. If you do end up braking the breather hose you'll also need the new alternator bolts to remove and reinstall the alternator.  There is no other way to stick your hand under the manifold to unplug the breather hose without removing the alternator.

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