E60 High Oil Consumption – Louder Turbo Whistling

Hi, I have noted important engine oil consumption. For
every 3,000 Km (1,900 miles) 1 litre of engine oil has to be topped up.

Furthermore when comparing the turbo whistling noise
to another vehicle of same model, same year of manufacture and almost same
mileage, its whistling noise seems 2 to 3 times louder.

Vehicle performance seems same, no power loss, no
visible engine oil leak (engine bay dry), not in limp mode.

When “hard heavy acceleration - foot flat down” start

on the red lights, cloud of smoke can be seen. When cruising during daylight,
no visible smoke can be seen. But when driving at night and having the
“following” car beam light from the rear (8-10m distance max), little smoke can
be seen when driving at 70km/h (44 mph).

In Mauritius, when the vehicle is checked by the

“turbo” mechanic specialists, 19 times on 20, the turbo are replaced.

I do not know if I am looking at two separate issues

or it might be that the turbo that is causing that high engine oil consumption.

I prefer to seek experienced advice for other causes

that might be causing this high oil consumption and “higher” turbo whistling
noise that has been around for more than 20,000 Km (13,000 miles).

Is it a DIY to access (peek inside) the turbo to check

the shaft bearings / scraping signs / broken-damaged blades / loose shaft movement
(up and down)?

How many turbo are there in that model? Some people

say that there are two !!!; 1 small and 1 larger?

Any other advice welcomed?

Thanks beforehand