Turbo whistling/whinning

Hi Paul,
I had this explained to me by the mechanic at AG Diesel when I had mine serviced. What he said about the whistle was it is caused by the gap between the edge of the blades and the inner wall of the turbo. Can't exactly remember, but it was along the lines of the amount of air flowing passed the outer edge as apposed to through the blades. Basically he said a snug fitting balanced turbo should have minimal whistle. In your case, if this noise has only just started, it could be bearings causing the shaft to shift horizontal/vertical position thereby atlering the gap between the blades and the inner wall. If you haven't had the turbo serviced, now might be a good time to spend a little $$, instead big $$ later.

Cheers,
Tony.

paul

I have an 8 month old TD 3.0L patrol too. Iv'e now done near 20,000km in it with no real probs. However, between 10,000 and 15,000km I noticed a definite noise from the turbo at the 2500rpm point. At slightly higher or lower RPM's the noise went away ?????
I changed my own oil at the 15,000 mark with that recommended by the handbook and the noise has gone. I suspect the dealership who serviced the car at 10,000km just put their standard bleep oil in it during that service.
According to the handbook, this motor is fairly fussy about the type of oil that goes in it. So be ware!!!! This may be you problem. I am not a mechanic but I think it has something to do with the ability of the oil to get up into the turbo. I intend bringing it up with my dealer at my 20,000km service. Trouble is, with the dunderclumpins behind the service desks these days, if they can't actually hear the problem then there's no problem!! They don't care. Thats why sites like this one are so good. With all our heads together we know more than the dealers do!!
Anyway, change you oil and see how you go.

Not all dealerships are the same but I for one got sick of been looked down at when ever I reported a problem with my vehicle. In some cases it maybe better to have the vehicle serviced by a dealership but in mine, I prefer to do it myself if possible. I am a mechanic by trade and can handle the general run of the mill things and if needed Im not scared to take to someone who is the expert in that field ie injectors, fuel pump etc
I dont beleive the dealerships offer a better service than others, in fact it maybe less some times but all being said taking your vehicle to the dealership to be serviced will maintain your warranty..This maybe important to you and resale value.
My humble thoughts.

Gary

Paul, all turbo's will make a whistling noise when working at compressing air into the manifold. The point of your question is, what is a normal whistle as compared to a problem whistle. I would suggest you trot down to another Nissan dealer and pretend you are in the market for a new truck, get a road test drive of a new one and judge the difference between it and your own vehicle. Bare in mind, that as the engine loosen's up and begins to make some horsepower, this also has an effect on the turbine speeds as well. A tight, new engine cannot expel the same quantity of exhaust as a "run-in" engine, and so as the engine begins to "go", so too does the turbo begin to do it's thing.