# Turbo cooling after shut down?



## NBrehm (Jun 27, 2011)

Maybe the fan?


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## bartonmd (Jun 30, 2011)

Owner's manual says the fan will only stay on for up to 4 minutes after shutoff...

Mike


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## eel1982 (May 26, 2011)

I've noticed this too! I thought I was crazy but yah, its like an intermittent humming noise.


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## Quazar (Apr 28, 2011)

Yesterday, right before this was posted I noticed it. It's not the fan, I was looking at it. Something does sound like it is turning on./off after the car is off.


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## bartonmd (Jun 30, 2011)

The water pump in this thing isn't electric, is it? (ETA: answered my own question... belt driven) Or an auxiliary water pump circulating water so if the turbo is hot, it doesn't boil the coolant in it?

Evap canister purge valve?

Mike


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## Ruger (May 21, 2011)

I've heard it too when i was changing my oil. Its more like a very low pitch buzzer, barely audible.


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## nickys68chevy (Jun 2, 2011)

I have the 1.8 and I hear the same thing, hours after the car is turned off.


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## Crewz (Jul 12, 2011)

Good to hear I'm not the only one that's heard this. It doesn't sound like a fan kicking on cause well, it doesn't sound like a fan moving air. It's more like the hum of an electric pump of some sort, but not as loud as an electric fuel pump priming.


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## limited360 (May 6, 2011)

I am not sure... but there is a fair chance this car runs an EVAP monitor leak check after engine off. Could be the air pump for this test. It would cycle during this test which can take up to 20 minutes on some manufactures depending on ECU strategy.


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## Crewz (Jul 12, 2011)

Nice. I didn't know cars did that. Sounds like a good theory.


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## nosro (Apr 11, 2011)

Emissions equipment has gotten incredibly complex. A long time ago, engine design was driven primarily by the desired power or mass. These days, emissions and diagnostics drive a far greater percentage of overall engineering effort. Thankfully, many things that improve emissions also improve power (such as improved fuel control). But not all.


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