Turbo - to cool down or not to cool down?

[Patrol-Guy]

So do turbos need cooling down for a few minutes before turning off the motor after a long trip or do you just turn the motor off and walk away??

[Winnie]

I don't switch off unless the pyro is under 150 deg

[threedogs]

Don't just turn it off after a long run, If you don't have an EGT gauge fitted and going on a trip and you have been sitting on 100kph.
when you get to your destination let it idle for a few minutes , this will allow temps to even out, and the exhaust temps to fall
If your just going to work unless you drive like Mario Andretti, by the time you grab your wallet, papers ,briefcase ,whatever should be enough time to let exhaust temps come down.
after all there is not rush, is there?

[the evil twin]

It's not so much the length of the run as the latent heat in the Turbo/Oil/Engine if it has been working hard.
If you fang it thru the 'burbs and screech into the driveway with EGT's up around 400 then it needs a decent cool down period.
If you drive 1,000 kilometres but the last few K's or so sedately and the EGT's are down then its OK to switch off immediately.

My rule of thumb is similar to Winnies...
If the Water Temp is around 87-89 deg AND the EGT is below 200 I'll switch mine straight off.
If the temps are higher then I'll select a suitable interval on the Turbo Timer or sit and monitor the temps are suitable before I switch off.

[the ferret]

If you could see the turbo during a long run at speed at night, it would be cherry red, they need to cool a bit before shutdown IMO.
Cheers, the ferret.

[AB]

I don't switch off unless the pyro is under 150 deg

You used to say 200 degrees, are you getting more delicate these days...lol

[entilzah]

Don't just turn it off after a long run, If you don't have an EGT gauge fitted and going on a trip and you have been sitting on 100kph.
when you get to your destination let it idle for a few minutes , this will allow temps to even out, and the exhaust temps to fall
If your just going to work unless you drive like Mario Andretti, by the time you grab your wallet, papers ,briefcase ,whatever should be enough time to let exhaust temps come down.
after all there is not rush, is there?

totally agree about the rush thing

[Winnie]

You used to say 200 degrees, are you getting more delicate these days...lol

That was the old turbo haha. This is the new one that I paid for with my precious dollars so I want it to last. Hahaha

[menis]

what are the side effects if you dont let it idle and cool down?

[P4trol]

Thea small layer of oil solidifies on the turbo/pipes (think a sort of cholesterol effect). Eventually the turbo can't be lubricated/cooled effectively.

[ben ren]

The oil bakes on the bearing journals and slightly damages the surfaces.Then the shaft picks up on the uneven spots which increases wear over time.
After that you will eventually get excess run out on the shaft and contact between compressor or turbine wheels on the housing,then it gets messy.

[Cuppa]

I don't have a turbo timer, but do generally try to let the motor idle for a little while before shutting off if it has been working hard. However there has been the odd occasion where without thinking I've just switched off, only to immediately think 'Bugger, shouldn't have done that'. On these occasions I have then immediately re-started the motor & let it idle for a while. Is it better to do this once switched off or not?

Cuppa

[ben ren]

Yeah it would be cuppa,the shaft and bearings would have a chance to cool down below oil burning temp.But shutting down hot a few times won't cause too many issues it's only when it happens regularly

[muz muz]

would it be worth having a temp gauge on the turbo itself?

[SonOf]

I used to wait until the egt registered 150deg before I turned off the 3ltr off. It used to idle for about 2 min.

Now I have a turbo timer in my TD42 and set it for 2 min as majority of my driving is at highway speeds and not hooning.

40818

[MoPatrol]

The oil in combination with the extremely hot turbo causes the oil to break down which becomes carbon that sticks to the walls of the oil pipes, gradually causing it to clog up up over time. Easiest way to cool the turbo is to back off your right foot a few km's before arriving at your destination.

[GU 2]

Its not so much the EGT's or the water temp to cool down, its the oil temp cooling down that's what's required.

[Chimo]

I have had my tubo on my GQ 4.2 since 1991 ish and also have an oil cooler and a timer and the timer always runs at least 1 min but 3 or 5 if towing or hyway driving.

Its still working so maybe a timer and oil cooler are worthwhile.

Cheers
Chimo