Redon
 

Why has my turbo (S12) 1.8...suddenly started whistling like a real high pitched scream?
Redon

one of the gaskets has probably started to blow, keep driving it hard and it will soon sound like a tractor:)

or the turbo blades have been damaged

or could be an air leak possibly from that very thin pipe that goes from the joint at the brake booster to the Boost sensor near the turbo

screaching is normally the turbo gasket just before as previously said it blows the gasket out and sounds like a tractor lol:p .

Try nipping up the 4 nuts up before she blows with a 13mm spanner :)


The nuts normally come loose because when the turbo has been changed the washers with tabs are not refitted before the nuts . ( they have tabs on them that bend down round the nut to stop the nuts coming loose)