Diesel Turbo idle down

Its one of the big questions I reckon Phil....would car makers admit that their engine should be cooled down everytime ?....
I don't think so....they want you to be attracted to the turbo power without knowing anything about hangups......
its probably a handicap to the bulk sales they expect. Mass marketers don't want cars with hangups.
With my 99 Jack, they reckon no cool down is required, BUT I always cool it down if its been running seriously.
I reckon we all have to read between the lines these days.....dp

I think the style of turbo matters. Is it oil only or water and oil cooled etc. I don't idle down. But I tend to be slack in many areas! Cheers Royce

phil from driving earth moving gear/ trucks im still in the habit of idling down particulary after pulling hard through sand, hilly country or towing having said that driving in city driving a idle down would the time it takes to undo the seat belt get your things open the door and shut down.keep in mind parking the car at low revs is cooling the turbo cya johnsy

Hi Guys,

Maybe wrong here (shoot me down in flames if I am) but in my days as a fitter the term was idle down the turbo, rather than cool down. I'm not picking fault but saying there is a distint difference that is self evident with the terms. I doubt that cooling down is an issue unless required by the materials due to extreme loads. However running down a turbo is to allow the turbine, if under high loads such as high way speeds, to run down from 100k rpm to idle. From what I've been told many turbines will drop onto a set of bushes at rest, hence the need for the rpm to me as low as possible and not at max. If anyone out there has experience in this area I be interested in knowing if this is correct with respect to today's commerical turbos.

Regards

Ray

i found this site
www.howstuffworks.com
when i was looking for info on turbos, very basic information and diagrams as well as heaps of links. It's a great site for any question you may have.

Dave

It's important to idle down as well as cool down a turbo, particularly if the engine has just been working hard.

As soon as the engine stops the oil pressure drops to zero - you don't want the turbo spinning with no lubrication so switch off after idleing for a few seconds at least.

As for temperature - if you switch off while the turbo is hot it can cook the oil which will leave unwanted carbon deposits on the turbo bearings.
The simple answer to both problems is go easy over the last few minutes of a journey, and once you have stopped the vehicle make sure the last thing you do before stepping from the vehicle is to turn off the engine.

Thanks everyone for the replies.
The turbo seems to have very low inertia because it responds almost instantly to throttle changes (the whine can just be heard). Because of this I will just allow the engine to work less hard before turning off. The same as I would do for any engine including lawnmowers! The last minute or so of a trip is normally at virtual idle anyway.
Phil

Hi Phil, if in doubt and you want to be safer than sorry, have you looked at a turbo timer? They are user adjustable, and guarantee an idle down time from 30 seconds to 5 minutes. Something else to consider. Bill Church