Clattery when cold
Join Date: Feb 2012
Location: United Kingdom
County: Greater London
It may slow down the problem but how well the flaps are spot welded to the spindles varies. Penetration seemed OK on all mine but some of the welds were way off centre on the spindle. The other problem is the top pivot, which is a pin just 2.5mm diameter into a tiny plastic bush. This wears laterally, which means the spindle shifts sideways in operation and jams the flap against the alloy of the manifold, stressing the spot welds. After that's happened a few thousand times the flap detaches and enters the inlet tract.
I don't personally think the oil and carbon gum plays much part in this.It is a soft gum, not hard, so gets easily pushed aside. My flap (I only found one, sat in the inlet) clearly shows metal contact marks - and was bent by the force. It may hasten failure of the top bearing, but basically it's under-engineered, poor design. Ned at Autolusso has said they've seen flaps fail in as little as 15k mls. My car lost 2 at 75k and the inlet was fairly clean with 2-3mm muck on the worst bits. They really are a "do you feel lucky, punk?" proposition.