I wanted to ask you how long should I wait before turning the engine off. Every day I come home from office I drive very hard until the moment I reach the garage. So the brakes don't have much chance to cool down which wouldn't mind as much as turbos, it can seriously affect their lifetime. What do you think?

I usually drive very fast (100-160Km/h), then drive slower for about half a minute and then I reach the garage and after few seconds the car is parked. Do you suggest waiting for additional minute or so?

 

I would either have a very gentle ride home for the last 5 minutes or if driving like you say I would leave the car on tickover for at least two minutes. That allows fresh oil around the turbo while it cools down on tickover.

 

there are different beliefs out there - some say, it needs to be cooled, some say the turbos are modern enough which requires no cooling.

I only turn off hte engine, if I was racing on the autobahn, need to take a piss so i rush into a gas station, slam on the brakes and quickly turn off the engine. only later while pissing do i realize that i might have done the car some damage

 

I wouldnt worry too much - driving hard might make you expire before your turbo eventually does

 

You are wrong .. The faster you drive, the sooner you get to your destination and that means you spend less time on the road. As you spend less time on the road, you will less likely get into an accident.

 

Yeah Ride hard, you can rest when you die

 

Oil serves two purposes - cooling and lubrication, so heat is only one problem here. A bigger issue is that the chargers will keep spinning for quite some time after the engine is stopped, and of course, there'll be no oil supply for lubrication. This will cause premature turbo bearing failure, which are simple brass bushes. Suggest you make an effort to let the engine tickover for 20-30 seconds to allow the turbos to spin-down to their lowest operating speed and this is easily done if you can let the car roll at tickover on final approach to your garage.
If you do have the mis-fortune of a bearing failure and the turbo shaft siezes in the core, it will snap, because the exhaust gases will keep twisting the turbine round - and when it snaps, your engine will white-smoke like a bastard as it runs on its own oil being pumped from the oil feed into the turbo, through the broken centre and into the intake compressor side. At this point, you are looking at a new engine - there is no way you'll be able to stop your engine from running on its own oil, until there's no oil left in the sump and the motor siezes. It will rev according to the oil being burnt as its fuel supply - which you will have no control of, and turning off the ignition will make not a scrap of difference.
If you have a manual box, you can simply drop the clutch and stall the engine. With an auto, you will cry. If you can starve the engine of air completely, it should stop and you'll have done well. This is something to be aware of on all turbo diesels, not just the 535d. Having two turbos means you are more likely to have a problem, due to higher boost pressures and side-thrusting on the turbos due to constantly changing loads that will eventually see the compressor wheel rub its housing and it'll be noticeable with a huge drop in performance.
Respect the turbos.

 

Turbo timer was popular back 10 - 15 years ago but it seems to disappearing for the past 6-7 years. Was it because most turbo car has integrating cooling system or modern turbo can stand the heat. However, turbo timer doesn't really work in a hot day. Actually the whole engine heated up more while idling.

 

What a great post! Thank you. It is very clear now. I will treat them with respect, that's for sure.

 

Excellent post, GeoffA!