Over the last few years there's been questions about the bubbling sound coming from the engine bay after switching off the engine and also about letting the turbo spool down before switching off the engine.

Well I've attached this video for you peeps to help answer your question.

I would guess that this coolest circulation is going through the turbo?

Mine does that too,you can hear it bubbling away even when inside the car, your engine bay looks so like mine ;) haha

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so does this prove that the turbo doesn't need to be cooled down be four turning off the engine as the circulating coolant will cool it to prevent any damage?

don't turbo run off oil to keep it cool and loobed?

Your car is bubbling due to the coolant system being over filled the tank you are looking at is a expansion tank and should and be filled half way between min and max to allow for the water to move as for the turbo cooling down its more letting your turbo slow down before turning off the engine to prevent starving the turbo of oil

When cold the coolant is just under max. Car is only 1 month old. I guess it's cooling the turbo as the liquid is being pumped into it.

turbo has a oil feed. not heard of water running thro 1 before

I think your right mate.

lol'ing dude haha

turbo has a oil feed. not heard of water running thro 1 before

Agreed but upon looking online fiesta st turbo has a water jacket for cooling just can't understand why it would still pump with the engine off

Whatever it's doing its obviously meant to. You see it instantly stopping bubbling when the little pump turns off.

water jacket...... this I didn't no..... sorry

I think it has a water cooled manifold. Could it be this ?

I typed in ford fiesta turbo water cooled on Google and the 1st site is fiestast.net it's on there about the water jacket for the turbo

http://fiestast.net/threads/the-official-fiesta-st-network-question-and-answer-thread.90/page-4

5th comment down

I was just going tp say isn't this what a timer is for? cool down period? wouldn't like to see the turbo if any of the water managed to leak onto it..... oops lol

Why cool it when the engine ain't running tho I thought it would need oil more than water to stop the moving part wearing

maybe they have had issues in the past with turbo's and people not cooling them down. just turning the car off after a run which just cuts the oil supply off...... but I have seen 1 lad whom owned a sti saw the turbo was hot ie glowing so he tipped a bucket of cold water over it.... this happened approx. 4 years ago......

another thing turbo's meant to have heat jackets to keep the hot air in due to performance? like u wrapping a downpipe and headers to keep in heat in?

Using the stop / start can't be good for the turbo. Maybe that's what the coolant is doing?

Using the stop / start can't be good for the turbo. Maybe that's what the coolant is doing?

That would make a lot of sense actually :P

It's just coolant going back into the expansion tank.. Where it comes from and how it gets there, who knows.

I don't know whether there's water jacket on the ZS turbo.. But I do know the water pump is mechanical. So when the engine is off, there are no pumps running.. Engineers are clever though, so as the coolant cools some siphoning effect might be keeping it in motion for a while.

Regarding the turbo and stop-start.. Oil pressure for lubrication would be more critical than it would be for cooling. I know the oil pump (again mechanical) has some special way of varying the pressure by means of a weird variable impeller inside it. That's got be be there for a reason.. And remember the actual turbine in the ZS turbo is tiny.. it doesn't have much mass... so its not going to be spinning very long at all after the boost is off.

It's electric. You can here it turn off

Definitely being pumped by an electric motor.

What I understand is water is pumped to help stop the oil from carbonizing inside the turbo

Finally settled this by asking the mechanic who last serviced my ZS. Haha.

There are two water pumps on the 1 litre ecoboost engine.

One mechanical one for the actual engine. And a small ELECTRIC one just for the turbo.

So there you are. :)

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In fact, a quick search on eBay and...

http://pages.ebay.com/link/?nav=item.view&alt=web&id=131482024946

you learn something new every day!

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