weird whistling/wheezing

Hi to everyone!
At first I must apologize for some language errors (I am from Serbia and so my English could be bad). Sorry for that!
I own a 2000 Freelander td4 with the 110hp engine for couple of days now and I have a quite disturbing whistling,wheezing during acceleration.My local mechanic here in town has checked all hoses from the turbocharger and intercooler with no succes.At the end he said to me to change the engine oil and all the filters because current oil is apparently bad and it affects on the turbocharger.Previous owner told me that he was changing the engine oil and filters just 3 month ago (shell helix 10w40).
I'm skeptical about it and I do not need the expense of 100eur unnecessary.

I would be very glad to hear yours opinions.
thanks so far

Tell your mechanic to check the hoses properly.
The most common cause is the long inter cooler hose coming from the front of the car......if you put your hand under it and follow it along it normally wears through towards the engine past where the oil filter youll find its been rubbing on a screw head that always wears them through

don't pay a mechanic, get someone to sit in the drivers seat and rev it while you look at the hoses.

undoubtedly an intercooler hose.