For our comprehensive fitting guide.
Click the image above.

The best solution is to eliminate the problem by removing the flaps completely.

The problem lies in the design of the inlet manifold, which includes butterfly flaps (commonly known as "Swirl Flaps". The idea is that by opening and closing they lengthen or shorten the effective length of the manifold which in turn should alter the torque output of the engine. The engine normally runs with the flaps open giving a shorter tract.

Unfortunately it isn`t known for them to break up and the consequences can write off an engine. Although the flaps themselves are made from plastic and will generally either lodge inside the manifold or simply pass through the engine without harming it, the metal fixings can be ingested into the cylinders.
The result can include a ruined piston, valves and cylinder head. while on their way out, the bits will also take out your turbo and just for good measure the catalyst too.

BMW addressed the problem by introducing stronger swirl flaps and larger diameter spindles - made from plastic - in 2006. This is no help to the owners of older models, especially as they are now coming out of warranty.

As a rough guide, engines affected will be those produced from 2001 to July 2005, although specialists report having seen engines from 2004 with the updated flaps fitted at the factory.
Although BMW UK will generally treat each case on it`s merits and "listen with a sympathetic ear" to any claims on a car out of warranty, the best solution is to eliminate the problem by removing the flaps completely.

It is not as serious as it sounds, since the effect of removing the flaps is apparently a very slight increase in emissions at idle and the car will drive no differently: off idle the engine runs with the flaps fully open in any case.
You will need to block the holes created by removing the flaps and spindles, and although you will see posts on the internet from people using epoxy glue and self tappers, who can trust them not to break free and get ingested into the engine one day

To do the job properly, visit our fitting guide by clicking on the picture at the top left of this page and purchase and fit the neat billet aluminium blanking plugs in the holes left in the manifold.

Swirl Flap Blank £12.34 (Small)

Swirl Flap Blank £12.72 (Large)

each plus vat and delivery.

If you are not sure which size you require , you can order a set of both sizes and providing you return the unwanted set within 14 days we will issue a credit on the returned parts. (Your postage charges not refundable)

To order, telephone 01502 500590 or
Click Here to go to our order page