A guide To swirl Flaps and removing them on BMW diesel engines

 For those of you that want to tackle the swirl flaps yourselves here's a few tips.

Firstly we use glass reinforced plastic swirl blanks because that is what the manifold is made from so it will have the same expansion rate with heat as the manifold itself.

Secondly everything has to be perfectly clean, dry and free of oil before reassembly. All mating surfaces and gaskets! An example of how clean I like to get them is pictured.

The gaskets are a good idea to replace at the same time. Make sure you use ones with double lip seals on them (picture) and that they protrude from the manifold enough to make a seal.

The blanks themselves must have viton or nitrile rubber o-rings that can resist oil so that they last a long time without deteriorating. Normal rubber o-rings won't last at all.

I won't go into details on how to get the manifold off and back on there are plenty of guides online for that. Just make sure all the orange bolt holders are there. If any are missing when you take the manifold off you have to inspect each port to make sure none have gone down into them unless you want a big bill!

Below Are some photo's to help you so you know what to look for.