timbeauuk

What does it do? I have WD40'd it and will get pliers to some time but is it important?

What is the valve on the underside of the exhaust side of my 300tdi turbo? It looks as if it might be a butterfly valve. Looking at equivalent units on 'google images', it is operated by an adjustable metal linkage that comes from a valve (Diaphram??) that has a rubber pipe from the inlet side of the turbo. Mine is siezed but the engine still seems to work perfectly well. Any help gratefully received.