this one new on me ,

usually in first and second gear on quite pacey acceleration i get a whistle start about 1500 rpm which then dissappears about 2000 rpm. if i ease of the throttle before it stops then the whistle changes tone as i go down to wards 1000 revs before going away.

i thought of a pin hole leak in the intercooler pipe as i have a 54 plate 2.0 tdci and found it to be a bit grubby so i put o new one on tonite.

the whistle is still there only o little better. just thought the turbo may not be running at 1500 rpm as my foot isnt on the floor.

wondering what it could be.any ideas or does it seem ok as i usually drive with the windows up and when i do i cant hear it!

ah just looked thru the lower grill in the bumper cos i could see oil dirty oil residue on it. can see a small radiator with what looks like intercooler pipes going in each end and there is dirty oil residue on the bottom of the radiator. could this be the cause of the intermittant whistle im getting and is the unit broken?

ok i have seen a diagram of the intercooler pipes and believe the offending item is the turbo intercooler which has oil residue on the botom. my questions are

does the oil residue mean its leaking and could this cause the intermittent whistling?

also what are the risks to namely the turbo?