N42 and N46 engine rocker cover gasket DIY

A common problem on the N42 and the N46 engine is the rocker cover gasket leaking. Also know as cam cover gasket.

The result is oil weeping down on to the hot exhaust heat shields, or the exhaust manifold themselves. This causes smoke from the engine bay and a smell of oil in the ventilation system, as well as the obvious loss of engine oil.

Here’s a brief guide to try and help and DIY owners who fancy taking on the gasket change themselves.

All you need for this engine is a decent set of tools. There is nothing special required, and the valvetronic motor doesn’t need to be removed either as the cover runs overs it.

So let’s start with removing the engine covering, cabin filter (micro filter) and the housing that the cabin filter sits in. There are some TORX screws holding it down.

You should the have this.


In the above picture I have removed the ignition coils, and started to move the wiring out of the way, which makes life much easier.

You must remove the eccentric shaft sensor connector, this is the round black connector you can see in the above photo. Be gentle and it’ll pull up without any problems.

Once the wiring is out of the way you should have this.


Now proceed with removing all the silver nuts that hold down the rocker cover.

Once it’s loose you can remove it and you’ll end up with this.


This particular car has previously had lots of engine silicone applied to try to seal it.

This is generally a bad idea and certainly not required.

Here you can see the black silicone, we need to carefully remove all of this without getting any into the engine.


Once you’ve removed the silicone, clean the contact surface using some brake cleaner, leaves a lovely oil free finish for the new gasket up seal against.


Now you need to remove the old gasket from the plastic rocker cover and thoroughly clean the rocker cover on the inside, paying particular attention to the gaps where the new gasket sits.

This must be oil free so take time doing this bit.

Old gasket removed.


Cover now cleaned and ready to install the new gasket. Note there are 2 gaskets for the cover, 1 smaller inner gasket and the larger outer gasket. Push this on and ensure sure it’s even and flat.

Note in this picture I am also replacing the eccentric shaft sensor seal, I advise this is replaced at the same time but it’s your choice.


Fit it all back onto the car and reinstall the nuts loosely until they are all in place. The begin tightening them from inside to outside.

Refit the coils and wiring, run the engine and inspect for leaks, once all confirmed ok refit the cabin filter housing and coverings. Then clean any old oil mess off your engine – voila, all done!