BOth good and not so good stuff here.
Obviously people all treat their cars differently, but the common denominators should be:
Regular oil changes, no turning off an engine you’ve just been thrashing.
My 53 plate 2.0 TDCi has just passed the 200K. Oil is changed every 5K, car flew through the MOT last month. No engine issues.
Turning off when the turbo is very hot is a bad idea.
While running, the oil lubricating the impellor shaft is being circulated.
Once the engine stops, the oil at the impellor shaft bearings ceases to be circulated.
So, if the turbo is hot, the oil is cooked, to the point that it burns and leaves fragments of the spent oil in the bearing.
Then when you start the engine, those deposits rip round the bearing before they are flushed away by the circulation of oil that occurs when the engine is running.
So, never turn off a really hot turbo, cos when you do, the temps sky-rocket and the oil left in the bearings cooks.
This is made worse by eaking out your oil changes for as long as you can.
Please remember, your oil gets everywhere with in the engine, and collects a lot of stuff on its journey like unburnt fuel which will effect its viscocity.
You may think you’re saving money by not changing the oil on a turbo car, but thats a false economy.
Change the oil, allow the turbo to cool before engine switch off.
Best just not to use the upper end of the rev-range once you are within 10 miles of your destination.
Leaving the car to idle to reduce turbo/oil temps isn’t a very good idea as the engine generally gets hotter, not cooler, when motionless.
;-)