Question for diesel drivers

[markjay]

Yes but... when sitting outside at a coffee shop, the bliss after the minicab driver stopped on the kerb next to you finally switched off the tracktor.... is unimaginable

 

[bpsorrel]

Ten seconds or so is enough to cool the turbo down. But, my neighbour who leaves his Vauxhall van idling at 5am outside his house while he loads up wouldn't even know what a turbo was so isn't allowing it to spool down (besides he's not driven anywhere yet!)

By the way, Vauxhall's 1.9 CDTI must be the noisiest diesel in the World. A GM/FIAT engine also shared with my old Saab. Total tractor of an engine!

 

[flango]

Two minutes for a turbo to cool down properly although modern engines can be less depends on configuration

Sent from my iPhone using MBClub UK

 

[developer]

I've never left a turbo diesel running to cool the turbo and I don't ever recall reading anything in the manual advising me to do so.

Re the Vauxhall diesel - I heard an Insignia start up yesterday - it sounded like a van.

 

[Bobby Dazzler]

Our W163 is a diesel, but I don't often drive it (now being used by the nanny). I always let it idle for 10 seconds before switching off, but before that I'm usual manouvering at close to tick over, to park. I wait for a few seconds in a petrol car too mind.

One exception is parking whilst towing, and I do this whether petrol or diesel. I try to coast in the final approach to slip lanes to motorway services, and leave the engine running before switching off. I do the same at the destination too, but you don't notice so much as you can unhitched whilst the engine cools.

 

[merc85]

i always let my Volvo t5 tick over for a minute after a run to let the turbo cool and compressor wheel unwind as they are oil and water cooled. as soon as you turn the engine off oil is stopped from the turbo but the blades will still be turning.

 

[Deleted member 65149]

Thanks for the info guys. I didn't know about the (disputed) need to let turbos run on for a while. But as someone else suggested, I doubt that the majority of drivers are aware of this. One of my diesel noisy neighbours is an international and League One footballer - so I'm surprised he even knows which pedals to press in his Audi A5 S 3.0 TDI! Another neighbour has a Ford people carrier thing that enforces the earlier post about how noisy Ford diesels are. Less noisy than those two, but still more than a tad noticeable, is the 2014 E350 CDI AMG a couple of doors away (but thankfully never left running for more than a few seconds). Perhaps I just suffer from sensitive hearing!

 

[Simon_M]

I think the letting the turbo spool down is an old story - modern engines normally allow the oil pump to remain active for a period after switch off to feed the turbo.

 

[V12]

I think the letting the turbo spool down is an old story - modern engines normally allow the oil pump to remain active for a period after switch off to feed the turbo.

How? The oil pump is directly chain driven from the timing chain?

 

[Howard]

i always let my Volvo t5 tick over for a minute after a run to let the turbo cool and compressor wheel unwind as they are oil and water cooled. as soon as you turn the engine off oil is stopped from the turbo but the blades will still be turning.

I don't know anything about turbos , but I thought they were exhaust driven ?

How can the turbo still be turning when the engine is off ?

Genuine question

 

[V12]

I don't know anything about turbos , but I thought they were exhaust driven ?

How can the turbo still be turning when the engine is off ?

Genuine question

Inertia.

 

[markjay]

Modern diesel cars have better insulated cabins, which is why the diesel rattle is hardly noticeable to the occupants once the car is moving.

Unfortunately the same can not be said for those of us who are outside the diesel car.

 

[johns E350]

My car does not rattle, it purrs. But it is a diesel. 350 CDI excellent engine won't have a bad word said against it.

 

[rf065]

I think the letting the turbo spool down is an old story - modern engines normally allow the oil pump to remain active for a period after switch off to feed the turbo.

No they don't, but it's a moot point anyway. The only reason they are left running is complete laziness. Once they've had one stolen and lost any insurance pay out, they won't do it again.

Russ

 

[Simon_M]

No they don't, but it's a moot point anyway. The only reason they are left running is complete laziness. Once they've had one stolen and lost any insurance pay out, they won't do it again.

Russ

OK then fusspot, it is an auxiliary pump that keeps running after you switch off the engine for a few minutes to keep the turbo bearings cooled.

 

[rf065]

OK then fusspot, it is an auxiliary pump that keeps running after you switch off the engine for a few minutes to keep the turbo bearings cooled.

I'm not being a fusspot, merely pointing out that the 99% of turbo engined cars are not fitted with such a system.

Russ

 

[V12]

Don't want to be facetious, but apart from dry sumped cars, are there any road cars that have an auxiliary oil pump? Not trying to shoot anyone down, but i'd love to learn a little here.

 

[Simon_M]

Auxiliary coolant pump

 

[rf065]

Auxiliary coolant pump

Again, 99% of turbos are not water cooled. The only reason letting the turbo spool down is not mentioned much anymore is because when turbos were first in use we were still running engines on mineral oil which turned to carbon and blocked the turbo's oil passage if it got too hot. Modern synthetic oils do not do this, but letting the turbo spool down is still not a bad idea.

Russ

 

[survey]

Again, 99% of turbos are not water cooled. The only reason letting the turbo spool down is not mentioned much anymore is because when turbos were first in use we were still running engines on mineral oil which turned to carbon and blocked the turbo's oil passage if it got too hot. Modern synthetic oils do not do this, but letting the turbo spool down is still not a bad idea.

Russ

Cars fitted with Stop/Start are obviously configured to safely shut down the turbo without causing damage?