1.8T engine - does it need to run at idle after use???

[a17aym]

Does the 1.8T engine need to be run at idle speed for a few minutes after use? I know this was a constraint of traditional turbos, but do we need to or does anyone here bother?

And before you say, I did try searching for an answer using the SEARCH engine but to no avail

 

[Anito]

Yes you should, especially after a long or spirited trip.

 

[monkeytrousers]

Nothing about it in the manual. I don't bother.

 

[madvw]

cooling down the turbo is a good way to make it last longer, just the same as warming it up before heavy use.

Living in a city, I have no other option than to warm down the car after a hiding.

 

[a17aym]

I dont give any time for the engine to rest as I always thought that the car was fitted with some sort of turbo timer which dealt with this problem - I wonder if anyone can confirm this?

 

[Adams3]

On the s3's im sure there is an auxillary water pump which runs on after the engine is switched off if the turbo is too hot, not positive though!!

Not sure about other models either, in fact not much help at all!! lol

 

[madvw]

no turbo timer on the S3 or 1.8T. Only the Aircon circulation runs on after switch off to prevent it freezing.

 

[Adams3]

Stand corrected then!!

 

[JamS3]

AdamS3 you are correct there is a water pump that runs to cool the turbo when the engine is turned off and you can hear it quite clearly when the engine is off and you stand at the front of the car.

When I bought my first S3 i asked the dealer if you should let the engine run before closing it down but apparently this is not required, probs best to though if it's had a good spankin!

 

[Adams3]

My friend at vw who works on my car told me thats what it was.

Appears he was right then!!

 

[JamS3]

Oh yes!

 

[madvw]

so the turbo is water cooled then? Some special garetts are, so i guess the k04 or k03 could be too...

 

[JamS3]

I'm not sure whether it's water cooled or its just a pump which keeps the oil running through the turbo so it does not dry like sludge with the high temps and the sudden engine turn off.

I'm sure its the latter, and I know someone will confirm this!...

 

[nwhiteley]

the auxillary water pump is not there to cool the turbo, but to help cool the engine down after the engine is turned off. all performance VAG cars have them, turbo and N/A engines. Both my 1997 vento vr6 and 2001 golf 4motion did.

S3's do not have a turbo timer, and therefore you should allow the turbo to cool down before turning the engine off. this because the oil will be no long circulating around the turbo and the oil left in the turbo can get too hot, causing it to thin and possibly burn off. as the turbo will be still spinning, there is a real posibility of bearing damage.

 

[madvw]

I'll eat my words!

looks like the K03 and K04 ARE cooled by coolant too. Oil is used for lubrication of the bearings, and as a coolant - but there is also a coolant layer surrounding the turbo...

So YES, the aux waterpump will cool down the turbo...

heres a diag of the connections for a 1.8T:

http://www.b5one.com/howto/k04.html

I didn't want to hotlink his piccy, so scroll down to the exploded of the KKK.

 

[JamS3]

I thought so!!

 

[god_thats_quick]

but if you've been giving it beans and you stop it doesn't help the issue with the oil in the bearings burning off and knackering the bearings as the turbo spins down, I always try and take it easy for the last few miles and let the car idle for a bit before switching off.

 

[nwhiteley]

I'll eat my words!

looks like the K03 and K04 ARE cooled by coolant too. Oil is used for lubrication of the bearings, and as a coolant - but there is also a coolant layer surrounding the turbo...

So YES, the aux waterpump will cool down the turbo...

heres a diag of the connections for a 1.8T:

http://www.b5one.com/howto/k04.html

I didn't want to hotlink his piccy, so scroll down to the exploded of the KKK.

if the turbo is watercooled, then the the aux pump will be of benefit to the turbo, BUT that is not the reason it is fitted. Every turbo car i have owned, 2 rover tomcats, a scooby, an evo, and my S3, have been warmed up and cooled down correctly, and i have never had a problem with the turbos.

 

[a17aym]

Turned out to be an interesting thread! Thanks for the responses.

I think in conclusion, we should at least, drive the car at just over idle for the last 2-3 mins of a medium-long journey, so as not to invoke the turbo.

That'll be pretty slow. but shouldn't be too difficult seeing as we live in West London!