Nissan Repair: Nissan X-trail whirring noise, nissan x trail, turbo replacement

Question
Hi, I have a Nissan X-Trail 2.2 Diesel SE on a 2005 plate. I have recently replaced the intercooler after the car started smoking a lot. There is now also a whirring noise that seems to eminate from the centre-left of the car engine bay while driving. I doesn't seem to be a wheel bearing problem as there is no extra noise while turning and is only noticeable after approx 25mph, but the pitch of the whirr rises with accumulated speed. It doesn't seem connected to the engine either as I have turned the engine off at 60mph and cruised and the noise is still there. The dealer instantly reccommended a turbo replacement (they would wouldn't they!) but how can that be if its not connected to engine acceleration? I've got a long trip coming up soon and I need to fix this at minimum cost, have you any suggestions please?

Answer
Paul,

If the noise is there with the engine off would lead me to think the rotational parts are making the noise.  If the noise is coming from the center left of the engine bay I would be looking at the front axle and bearings on that side.  Get the vehicle up on a lift and inspect the rotating assembly, tyre and all, and see if you have a noise.  I have had several automobiles on a lift, running, to simulate road conditions.  Email me back if you require more...