swirl valave is located near inlet manifold on Vauxhall engines and could be the problem, however when it is a problem the engine has a loss of power. As you say car running well I think that there may be an exhaust leak which you should hear. Suggest you take it to local dealer to have a look at.
sorry cannot offer any other ideas
maurice
December 2009
05 19cdti 150bhp the soot is on the left hand side of the engine bay only ? thanks..
ian
December 2009
What make and model of car and what engine.
If it is diesel maybe exhaust manifold to downpipe leak would expect soot from diesel more than petrol engined car.
Is there a thicker layer of soot in one area of the engine bay or an even covering.
Maurice
December 2009
yes m8 its soot
ian
December 2009
Are you sure it is soot. Might be a drive belt breaking up.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cars.