320 D engine tone from cold start
On these cold mornings, there is a medium tone/pitch noise which increases when the engine is revved. I can only describe this as 'turbo whistle'. This does go completely once the engine has warmed up after a mile or two. Is this normal because I have read somewhere that the turbo's work differently until they have reached optimum temperature. Does your 320 D have this characteristic?
Thanks in advance.