Have Land rover discovery that when driving makes a loud whining noise, when i lift the bonnet it seems to be coming from the turbo. Is it likely to be the turbo or could it be something else.

Hi welcome main problems are the abs valves causing the 3 dash lights (search 3 amigos online) a really badly sited compressor can cause air suspension models to fail giving the bags a slow leak the V8 is a solid engine but can have radiator expansion tank and cap failures
the other issue is electrics windows and door looms are problematic

Tons of possibilities here (transmission, differential, motor mounts, transmission mounts....), so I'll ask some debug questions to help narrow it down. Does it make the noise when shifting into reverse? Also, does it make the noise only when shifting from park, or also when shifting from neutral (into drive or into reverse)? Did the noise start as an occasional, softer noise and get worse over time, or did it start suddenly? Does the vehicle lurch at the same time as the noise? What happens when you go from Reverse to Drive, or vice versa? Has any work been done recently (brakes, tires, alignment, suspension, transmission)?

you can not put oil on yourself. You have to visit a qulified garage where they know how to do it. The oil goes with the same machine which is putting freon gas in the ac compressor.

check in the `power distribution box under the bonnet could be a main power fuse or a corroded fuse holder in here

Could be the universal joints in the drive shaft

built in the UK god save the queen ---- look on the opposite side of the car ,they are all kack handed in uk and drive on the wrong side of the road so chances are its on the passenger side .

In the engine fuse box under the bonnet ,relay is the closest one to the front of the vehicle ,about £7 to replkace

Sounds Like Pinion Bearings , But Carrier Bearings Should Be Replaced (In My Opinion) as they Could Be Contaminated

check all the pipes for cracks turbo sounds like its doing its job but may be a cracked/split intake Hope this helps

Check the turbo hoses.......One hose must damadged.....Reply me....I'm working for Landrovers..Specialy 300tdi.....
Ruwan.