# Turbo timer/ Cooling



## 70AARCUDA (Nov 14, 2010)

...with the current *cold* weather, I think that question won't be answered until summer when *hot* weather happens.


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## itsbmw (Feb 5, 2011)

70AARCUDA said:


> ...with the current *cold* weather, I think that question won't be answered until summer when *hot* weather happens.



That's what I was thinking, we can only wait and see


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## Spaceme (Jan 20, 2011)

When I have any doubt as to whether I need to allow the turbo in my Cruze LTZ to cool after driving, after I turn off the ignition and get out of the car I remote start it. It will then idle for 10 minutes then shut off.


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## robertbick (Jan 1, 2011)

I wonder if some of the people that are concerned about cooling their turbo after driving hard have also complained about the gas mileage?


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## nickauger (Feb 11, 2011)

Its important to cool the turbo when you're hitting full boost just before shutting off the engine. You can let it run at idle for 30sec and it will be Ok. It is more important to let it run idle, when you have ball bearing turbo, cause when you shut down the engine, the turbo is still spinning with no oil pressure.


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## Blue Angel (Feb 18, 2011)

^ Heat soaking the turbocharger is the issue as a hot exhaust housing can "cook" the oil in the bearings if there's no oil/coolant flow through the turbo's center section after the engine has been shut down.

A ball bearing turbo "coasting" down with no oil flow doesn't cause excessive wear, it's the journal bearing turbos that have issues with this since the journal bearing depends on a pressurized film of oil to keep things floating at a clearance.

Cooking the oil in the center section is an issue no matter what type of bearing is involved. It's generally advised to let the engine idle for a minute or two if the engine has been run hard just prior to parking the car. It's kind of surprising that OEMs generally don't incorporate some sort of timer to allow the engine to idle for a minute or so under certain conditions before shutting down.


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## 70AARCUDA (Nov 14, 2010)

...and, _"...cooked oil..."_ is one of the reasons GM has dictated the use of *dexos1*™ compliant motor oils...it's _ashless_.


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