Turbos and cooling down

Steedie

Steedie

Steedie

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Joined
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On your average turbo, how long after a spirited run should you leave the car to cool down before turning the engine off?

I always sit there for 2 minutes then consider that enough but tonight a guy happened to be outside his house, and when I got out he asked why I'd been sat with the car running. I explained and he said 2 minutes is no where near enough.

Also, say you turn your engine off straight away, as I understand it, the issue with this is oil still in the turbo dries and clogs up, does this mean when you next drive with a heavy foot, does this clogged oil get removed when everything gets hot again?

Cheers
 
my understanding is the oil in the red hot turbo stops circulating when the engine goes off and the red hot turbo burns it onto whatever surface is nearest
 
Less of an issue if water cooled really, and ideally you want manual fan override for the idling phase to cool off the engine and oil.
 
My car comes with an electric pump as standard which runs after you switch the engine off for as long as is needed until it's cooled down enough, which is a nice feature and means not having to worry about doing this.
 
It may be worth investing in a turbo timer, imagine if you summed up the time spent over your lifetime waiting for the turbo to cool.
 
I just drove off-boost for the last portion of my journey usually, but would leave it a few minutes if I'd been on a hard run.
 
[TW]Fox;18657734 said:
A turbo timer on a 2 litre diesel? Seriously?
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Well if he is spending that much time waiting for the turbo to cool then yes. Granted, most of us, given a 2.0 diesel wouldn't bother waiting for the turbo to cool.

I guess it depends how much you value your free time.
 
After a hoon I'll let the car idle for 2-3 mins, though it's far easier to just drive gently for the last couple of miles. Turbo timers are largely pointless and it's technically illegal to have your car running unattended.
 
If the manufacturers thought there was a need for a turbo timer or electric oil pump they would have included one by default and you may find that you have a pump. :)

I've got a turbo timer that i rarely use, the last minutes of my journey no matter where is always through residential streets, plenty of time to let the turbos to cool down.
 
30 seconds to a minute after about 5 minutes of driving off boost. Must work as the original turbo is still going strong past 180k. Decent oil and routine servicing will have helped obviously.
 
With water cooled turbos its not really an issue, it was back in the day when it was just oil and the owners manual would state to let the engine idle if driven hard before shut off.

Another good reason to change oil on turbo cars in between recommended changes also and don't scrimp on cheap oil.
 
MikeHiow said:
I just drove off-boost for the last portion of my journey usually
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When I had a petrol turbo this is what I did.
Now I have an agricultural TDI I don't really drive hard enough to justify it.
 
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Gaverick said:
It may be worth investing in a turbo timer, imagine if you summed up the time spent over your lifetime waiting for the turbo to cool.
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I thought they were illegall? as your not allowed to have the car running when you arnt there

in reference to the first question, dependant on how spirited the drive ill leave it anything up to a minute after I have parked and ready to get out
 
My last few mins of driving are always through residential streets so mostly don't worry about it. However if I have been hooning it a lot up until the 30 zones I tend to leave the engine running whilst I get my coat etc and then switch off.
 
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