I now have a new noise on my td6 when I pulled out to over take a lorry yesterday I heard a new whine/ whistle noise on it. It is not the normal turbo whistle as its a little louder and comes in slightly after the turbo whistle, it will only make the noise under load when driving, so when its in neutral no noise. but I still think it could be possibly be boost related ? the car is not down on power and there is no more slip with the transmission so don't think it is the auto box. Has anyone else had a similar issue or a clue what it could be?
Cheers Roger

My alternator whined just before it went could be related maybe a slipping sepentine belt or similar? Present :2008 TDV8 HSE
Gone Audi A5 2.7TDI
Gone Discovery 3 HSE
Gone Mercedes CLK
Gone Range Rover 2.5 DSE

Check all the pipes for a split that would give a whistle

Check the intercooler hose, there may be a split or a small hole that's leaking when the engine is under load. I have a similar very slight whistle under load, need to check my hose, but not got round to it yet, as no loss of power.

Have similar on my disco, sounds like someone blowing over a bottle, sure its a hose but cant be bothered to check, its in for a service in friday so they can look then. There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
2021 Discovery 5 D300 MHEV commercial

Thanks for all the answers will have to get the boost pipes off and have a look
Cheers roger