Turbochargers

I was taught to let the turbo slow down and cool down before shutting off the engine and is something I still do now. Now days all trucks, machinery, diesel 4x4's (and some cars) have a turbo but no one lets them cool down and there doesn't seem to be a problem. My own D4D Hilux has nothing in the owners manual about it but I still wait before turning it off. What has changed? 

Good Call Sbound
With our depot @ the bottom of the hill
we B mainly cruisin n not laborin the motor
and by the time we back it up into the shed we just shut m down.. 99% of time MT travel back to the yard
Horses for Courses

nother Q:

how important is it to cover the exhaust in transport
tractors and trucks never cover exhaust in there sales yards

WotSezU

cya
 

I'm with Swishy, backing off well before parking, giving the temps a chance to stabilise. If I can't gently roll to a stop, I give any motor, turbo or NA, a minute to settle.
Supposedly modern oils are supposed to negate the need to idle down, but my habit prevents another thing you hear nothing about these days, afterboil, which is also avoided unless there are other issues. 

We just took delivery of a 2023 Mercedes Sprinter to transport her dogs and it shuts itself off when it stops at traffic lights.

I assume if Mercedes programmed it into the van they mustn't see a problem with it.

I turn the function each time I drive it.

My wife is still getting the hang of it.

Any turbo engine aircraft I ever flew had a 3 minute shutdown from flight power. If you landed and had a long taxi at low power it can be counted in the time. If you land at a country type strip where the parking bay is just off the runway you have to sit at idle until the 3 minutes are up.

We were told shock cooling by sudden shutdown can lead to cracked turbo blades.

Turbine/jet engines have the same cool-time rules.

I think with vehicles they almost never go from sustained high power revs to shut-off like aircraft and normal shut-offs happen after low power/low temperature situations say on suburban streets. I certainly don't worry with my Navara on daily drives but if I pull in to a parking bay on the highway I let it idle for a short time before shut-down. Don't know if it is necessary but can't hurt.

Lang

I reckon I cracked the turbo's exhaust housing when the exhaust brake jammed closed and the EGT's momentarily climbed to 700+. 
The only way to stop it climbing was to shut it off.

edit:  Found a photo showing the crack. 

Every Turbocharged Motor I own (Including  My Ute) has one of these fitted..!

 

Old Bulldozer Bloke  knew as big Kid, used wind every Motor of His over with the Stop knob out until the oil pressure went up, then push stop knob in to start. !!
His theory was the turbo never got run dry..

I'm with Lang in that a little extra idle time after a fast run can't hurt.

I'm not sure Mercedes would approve of me fitting a timer but I DO think they are a great idea.

Our 2020 Hiace has the same function. Depends on how hard you your foot on the brake. Lightly does not shut it down but I too disable the function. Engine stops so does ac

I think it’s good practice to allow all hot components to reach a more stable temp.
It’s easy to cook oil in a quickly shut down turbo which is designed to flow oil through and away, not simmer at extreme temps.
Ball bearing cartridges have restricted oil flow so they’re not quite so affected as bush bearing designs which need a lot of oil to maintain the fully floating assembly.
Bonneted 680 turbo Leylands had this issue, turbo was rear mounted hard against the firewall, pretty sad.
I’ve never had a wheel fail from overheat, they’re made from amazing materials, ceramics the works. Ceramic ball bearings are also available. Glueing the ceramic wheel to the shaft is where most fail from over speed.
Had my D4D turbo go into siren mode. They have a trap built in. Toyota thought a plastic in line filter before the MAP sensor was a good plan but the flimsy filter casing splits with age and then the turbo will over speed.
So I find it strange that Toyota opted for a twin turbo hot vee arrangement in their 300 series. Imagine the under bonnet temps.
A hot vee in Aus? Not for this old codger.