Turbo engine cooling time?

[skyblues11]

Hi All,

i have been looking into this subject about prolonging and caring for a turbo engine.

in today's technology, do we still need to wait for an X amount of minutes before switching the engine off?

Its not very convenient to be honest. I have seen var. articles suggesting you should wait 1, 3, 5-10 min. on idle, before switching off.

i can appreciate it after a long journey of about 1hr+, but I can't spend 5 min on 3 short journeys i might do on a typical day.

do you wait until the turbo cools down, and if so, how long?

[samdub]

I normally wait around a minute on short journeys and 3 mins after a long stint. That said, I don't have any evidence to say its working but in my head it's a contribution at least.

[maisbitt]

How long do you want to keep the car? If you're leasing over 2/3 years or replace when the warranty runs out then it's not a concern.

Not sure how reliable newer VAG turbos are in the long term as i've never had a VW (for the last 5 cars) longer than 2.5 years.

My boss has a 14 year old Passat TDI with 170K miles and still on the original turbo, doing about 25k miles a year (not sure why - he must be on about 70 grand a year!)

[true romance]

I've had turbo cars in the past and only left it to over run for few minutes when its been raced hard and the turbo as been used alot. If I've parked up after normal drive I just switch it off. Not sure if this is right or wrong but never had any issuses with the turbo.

[rocknob]

As far as I can remember the Scirocco's have a electric pump which circulates coolant through the turbo when the engine is off...

[jammyd]

The new breed of VAG Engines and electronics, will kick in the fan and coolant once you stop the engine if there is a need to continue the cooling of the turbo...

I remember a particular run along the A303 and through Salisbury plains where I pulled up in Hungerford and got out the car to hear the fan going like the clappers, quick run in to Tesco and back out, and finally as I got back to the car the Fan went off...

[ZephyR]

I seem to recall having read somewhere that it is not necessary to allow the engine to idle to cool the turbo with these new modern engines. Just can't remember where I read it

[gio_italy]

I seem to recall having read somewhere that it is not necessary to allow the engine to idle to cool the turbo with these new modern engines. Just can't remember where I read it

http://www.volkspage.net/technik/ssp/ssp/SSP_359.pdf" onclick="window.open(this.href);return false;
page 19 says

"A circulating pump ensures that the turbocharger does not overheat for up to 15 minutes after the engine has been turned off."

So, I guess that leaving the engine idling for a few seconds/minutes is really not required.

[Shaun]

I have had quite a few modern turbo cars and my cooling period is as long as it takes me to turn the key in the ignition after I have pulled up :-)

[skyblues11]

I guess in short journeys, the turbo does not get hot enough to need cooling, especially in typical slow rush hour traffic.

Furthermore, according to that diagram from the volkspage.net, that its the supercharger that work with the low rev, rather than the turbo.

[skyblues11]

i was reading that volkspage.net. Since when that Brasilian VW director was so caring in making a First Aid manual? its like a paramedic training course!

[peter.vw]

I seem to recall having read somewhere that it is not necessary to allow the engine to idle to cool the turbo with these new modern engines. Just can't remember where I read it

http://www.volkspage.net/technik/ssp/ssp/SSP_359.pdf" onclick="window.open(this.href);return false;
page 19 says

"A circulating pump ensures that the turbocharger does not overheat for up to 15 minutes after the engine has been turned off."

So, I guess that leaving the engine idling for a few seconds/minutes is really not required.

Hi found the link fascinating is there a page for the tdi 170 and 140

[gio_italy]

The self-study programme for the 140hp TDI Common Rail engine should be ssp403.
I've just tried to google for it but unfortunately I couldn't find it in English. German and French editions are widely available though.

Gio

[Sanders83]

I just make a point of driving the last few miles slowly and gently and keeping it off the turbo. Normally the oil temp will drop by a few degrees by the time I pull up so that covers my peace of mind.

[gio_italy]

I just make a point of driving the last few miles slowly and gently and keeping it off the turbo. Normally the oil temp will drop by a few degrees by the time I pull up so that covers my peace of mind.

Well, I guess you cannot go wrong by waiting a few seconds before switching off.
However I suspect there is not much relation between oil temp and turbocharger temp. The former is usually in the 90-100 C degrees range whereas the latter is an order of magnitude higher (under the assumption that turbocharger_temp ~= exhaust_gas_temp which may not be completely true), has a much wider operating range and drops/rises much faster. See the following post by RW1:
http://www.sciroccocentral.co.uk/forum/ ... 249#p56716" onclick="window.open(this.href);return false;

[kanar]

IMHO the temp. is not the only issue. It's about the oil circulation in the turbo.... I try to cool it down before switching off and I am sure that it necessary(according to VW service).