Saturday 19 July 2014

E60 530d: Swirl-Flap Blanking Plates

If you have a BMW with swirl-flaps, get them out ASAP. We all hear horror stories about swirl-flap failure and just how bad they are, but I had no idea they can wreck your engine so quickly and overlooked the advice. This I have lived to regret, as have a thousand others. Just one flap breaking loose, as in my case, and being sucked into the engine does all that damage. Do yourself a favour if you have 100k on the clock and fit blanking plates. Some say the engine won't run properly without the flaps, but I am assured it will and for a lot longer. All the swirl-flap is designed to do is to dump air into the engine when the inlet-pressure is reduced and soot would normally be dominant. In other words, it reduces the little puffs of black smoke on harsh gear changes. The car will still pass MOT and won't use any extra fuel.

I got some aluminium ones off eBay, they were £20.99 delivered for a set of 6, sets of 4 are even less.

My late-2003 M57N 530d has the earlier 22mm swirl-flaps and so should most 4 and 6 cylinder diesels up to about 2006. Revised M57N should have the beefier 33mm flaps, but after 2010 the swirl-flaps are removed from the inlet and redesigned entirely. Hmm, I'm amazed it took them so long. The actual specific size of swirl-flaps in BMW diesels from 2003-2010 varies wildly it would seem, so the only way to know for sure which ones you have before buying is to remove the inlet-manifold and measure them.

SIZE refers to the diameter of the hole that the swirl-flap fits into, not the length of the flap in the inlet port!


1. Remove inlet-manifold.
2. Remove the two screws holding the swirl-flap diaphragm on the underside of the manifold using a T20 Torx socket.
3. Slide the metal-rod clear of the swirl-flap levers and remove it with the diaphragm.
4. Remove the two screws holding each swirl-flap in place using a T20 Torx socket.
5. Remove the swirl-flaps by prising either side evenly with a flat-screwdriver until it pops from the seal and can be lifted out.
6. Fit the swirl flap blanks into the holes and pop them down into the seal - they should self-align.
7. Replace the twelve T20 Torx screws to the blanking-plates.
8. Unfasten the extended part of the lever-arm that joins the swirl-flap diaphragm to the metal rod and remove it along with the rod.
9. Refit the diaphragm to the inlet-manifold with the two T20 Torx screws.
10. Replace inlet-manifold.

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