Diesel Swirl Flap Removal

Swirl flap failure...

There is a common association with diesel engine swirl flap failure and catastrophic engine damage. BMW engines M47tu and M57tu possess small butterfly valves also known as swirl flaps within the inlet manifold to improve emissions. The purpose of the swirl flaps is to allow an elegant control of air turbulence through the inlet tract to aid combustion under light load. However, the mechanical steel part originally manufactured saw numerous failures where disintegrated sections of the swirl flap, screws or debris fell into the engine. Potentially damaging pistons, valves, injectors, the cylinder head and as the debris passes out of the engine the turbo & CAT. Despite a redesign of the valve, further failures are still being reported of engines up until around 2008.

Prevention is better than cure!

The failure may be averted prior to any catastrophic damage though, by the simple replacement of these swirl flaps with a specially designed set of blanking plates. The removal of the valves will have no noticeable effect on the performance of the car and emission values will remain within specified guidelines. Prevention is better than cure! If you are unsure if your BMW diesel engine has these ‘swirl flaps’ or perhaps you are unsure if they have been previously replaced or not give us a call and we will be happy to advise you.