Member Since: 03 May 2016
Location: Kent
Posts: 1521
Spooling down for better turbo life
I always keep my engine running for a couple of minutes (turning Eco stop/start off to ensure the engine doesn't stop) after a long run. When I had my X-trail this was recommended in order to ensure the turbo was cooled down prior stopping. This was known as spooling down.
I asked the dealer about this when I purchased my Discovery and was advised there was no need. What is the advice from knowledgeable forum members on whether this is required? Obviously can't do any harm but am I wasting my time? Given the number of turbo failures on Discoverys and all other cars, should this be recommended and if so does stop/start interfere with it?Gary
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Discovery 4 HSE 2016MY
8th Jun 2016 6:14 pm
adam
Member Since: 20 Sep 2005
Location: Home and Happy
Posts: 6917
Following advice on here a few years ago, always let mine warm down
8th Jun 2016 6:18 pm
Moo D3 Decade
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Always let mine warm down. 11 years and 191k still on the original turbo. New Defender L663 110 SE (known as Noddy!)
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8th Jun 2016 6:25 pm
Gareth Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26701
If it was a petrol turbo, I would say definitely yes, let it cool a bit. But I'm not sure it's necessary on a Diesel engine. I have never consciously let my D3 or my 4 idle for more than it takes to put it in park and apply the epb.
I had a 2.0 petrol turbo Citroen in the past, and the turbo cracked because I shut down too soon after a fast motorway run. Mind you, it was made of cheese like the rest of the car!
From Cummings, but IMHO applicable to any turbocharged engine:-
Quote:
Good operating practices
Owners can help themselves to get maximum service life from their turbochargers if a few good practices are followed:-
Start Up
When starting the engine use minimum throttle and run in idle mode for approximately one minute. Full working oil pressure builds up within seconds but it is useful to allow the turbocharger moving parts to warm up under good lubricating conditions. Revving the engine within the first few seconds of start up causes the turbocharger to rotate at high speeds with marginal lubrication which can lead to early failure of the turbocharger.
Shut Down
Before shutting your engine down, let the turbocharger cool down. When an engine runs at maximum power/high torque, the turbocharger is operating at very high temperatures and speeds. Hot shut down can cause reduced service life which is avoidable by a minute or two of idling.
Allow your engine to idle for 1-5 minutes to allow the high temperatures and speed to reduce and so prolong the life of your turbocharger.
Engine Idle
Avoid running your engine for long periods in idle mode (greater than 10-15 minutes). Under idling conditions low pressures are generated in the turbocharger which can cause oil mist to leak past seals into the two end housings. Although no real harm is done to the turbocharger, as load is applied temperatures increase and the oil will start to burn off and cause blue smoke emission problems.
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8th Jun 2016 6:34 pm
lynalldiscovery
Member Since: 22 Dec 2009
Location: Maidstone
Posts: 7274
I assume like most people the last couple of hundred yards are driven slowly for parking shunting etc? if so no worries on shutdown, even coming off a motorway into the services the last bit is again slow speed work.
8th Jun 2016 7:44 pm
Disco_Mikey
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 20731
Always done it, with all my Turbo'd cars, petrol and diesel.
Member Since: 30 Aug 2014
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This is a good point. Thanks for the reminder 2011 - 2015: 3 x FL2
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8th Jun 2016 8:08 pm
James W
Member Since: 27 Mar 2008
Location: Wirral, UK
Posts: 3067
I have a pre and post-drive procedure that would (probably not) impress a 777 pilot. It drives SWMBO mad. She turns her engine off on her car before it rolls to a stop on the drive
I have to power everything down (radio, fans, etc.) before I switch off. Just a bit OCD.D4 XS, gone, much loved, never forgotten
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8th Jun 2016 8:14 pm
Robbie
Member Since: 05 Feb 2006
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I've always allowed the turbo(s) to wind down but this is usually by driving gently rather than standing at idle. About the only time I have to make more of an effort is when stopping at a motorway service station. For me this has always been about preserving oil pressure whilst the turbine is spinning.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 25 Apr 2015
Location: Suffolk
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Me too. I always allow the engine to idle for a while before switching off. Old habits die hard.
I remember my father-in-law, long dead, admonishing his daughter, my wife, for reving up the engine on his Mk10 jag then switching it off at peak revs. She asked why she should not do that.
His answer was - " if you do that you leave all the pistons at the top and that makes it harder to start next time." She said OK and has never done it since.
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Mechanically impossible to have all Pistons at top...
But to me a pointless waste of fuel...regardless of whether it's petrol or diesel...
Letting the turbo charger cool down means reducing tha carbonisation of lubricating oil fed to the turbo...to me a good practiceBREXIT - done properly.
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8th Jun 2016 11:02 pm
LandPhil
Member Since: 25 Apr 2015
Location: Suffolk
Posts: 197
Wow! is that true?? FFRR Westminster TDV8
D4 HSE MY12 Aintree Green. Great car
RRS HSE Lux MY11 Stornoway Grey
Freelander2 SD4 HSE-Best car I have ever owned.
any multi cylinder internal combustion engine has a firing order or sequence - a sequence of individual cylinders either drawing air in, compressing, firing, exhausting & these are set apart governed by the crankshaft / then the camshaft/s.
its physically impossible to have all the pistons at the top.
what your late relation was maybe saying was to stop the engine at a rate higher than tick-over speed wasn't good...but stop any engine & the whole thing stops turning eventually & comes to rest one cylinder or another is going to be at some point in its cycle & its next door neighbour another point
letting the engine idle for say the time it takes you to take your seat belt off & gather your belongings (20-30 seconds maybe) to me would be worth it as it allows the turbo to cool a bit from its running temperature...remember this is a gas turbine that gets to engine exhaust temperatures 6-7-800 degrees C........its fed with engine lube oilBREXIT - done properly.
Right now ...We need Government - not Politics
Save the Dipstick Flagbearer-keep it simple, less likely to fail campaign-agenda items:Starting Handles, Acetylene Lamps.
Founder: Dipsticks-R-Us Inc
D3 HSE-perfectly formed, passenger friendly...has real DIPSTICK
Jag XK-but sadly no DIPSTICK...HUGE design fault
FL2 has DIPSTICK..."real comfort in rear seats"
VW Golf wondermobile (?)..has real DIPSTICK
Morris Minor..original DIPSTICK technology..and a real KEY.
9th Jun 2016 8:43 am
Gary_P
Member Since: 03 May 2016
Location: Kent
Posts: 1521
It seems that the consensus is that it is probably a good idea to spool down after a long drive before turning off the engine. What about the second part of my original question? Does stop/start interfere with this? I had a situation just today after an hour and 15mins on the motorway, off via the slip road, and held for a few minutes with lights. Stop/start kicks in . Does cooling the turbo continue when the engine stops via this method or is stop/start bad for turbos?Gary
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