Do intercooled turbos need to be cooled down after use?

Submitted: Friday, Apr 08, 2005 at 01:30
ThreadID: 21873 Views:2905 Replies:6 FollowUps:3
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Hi Guys,

I have just purchased a 2.5lt Intercooled Turbo Diesal Courier and I am wondering if I must let the engine idle for a few minutes for shutting of the engine?, so that I dont damage the turbo.

Or does this only apply to a turbo that does not have an intercooler.


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Reply By: Member - Michel D (Int) - Friday, Apr 08, 2005 at 06:08

Friday, Apr 08, 2005 at 06:08
An intercooler just cools air after it is compressed by the turbo. It doesn't help you or your engine in anyway to preserve these expensive turbines. By cooling the air the volume of the air decreases and by doing so even more air can be compressed into your cilinders.

Leaving your turbocharged engine running idle for a minute takes care of the fact that your Turbo's need oilpressure for there bearings. Turbo's spin at high rev's and will keep on revving for a while after you released the throttle. Also the cooling down proces is much nicer this way (oil cools also)
Take look at this picture, then you know why to cool down easily ;)

Good luck
AnswerID: 105693

Follow Up By: Member - Chris M (QLD) - Friday, Apr 08, 2005 at 10:50

Friday, Apr 08, 2005 at 10:50
Totally agree with the above.

Have been told about 45 seconds for round town driving, and up to 2 minutes if coming off highway and stopping straight away.

In the alternative, if you a exhaust temp guage, shut down at 150 degrees.


FollowupID: 362834

Reply By: Wizard1 - Friday, Apr 08, 2005 at 11:47

Friday, Apr 08, 2005 at 11:47
Have you checked your owner's manual. Mine recommends minimum idle down times depending on speed and driving duration.

You'll generally find that running around town the turbo isn't constantly at high engine speed and revs so "may" not need to be idled down for extended periods. I find by the time I pull up, open the gate, the garage and drive/reverse into the garage it would have idled down.

On longer trips at speeds above 80 kph, especially when towing, I idle down for at least 3 minutes.

But everyone will have an opinion on this topic just like everyone has an !@#$hole.

If your worried get a turbo timer fitted.

Prado TD (intercooled)
Gold Coast

AnswerID: 105718

Reply By: Rob! - Friday, Apr 08, 2005 at 11:48

Friday, Apr 08, 2005 at 11:48

When I bought my car it was fitted with a turbo timer. The turbo timer has an auto function which sets the time required for idling according to the temperature (I guess).

Whenever I travel from Noosa to Brissy I get the following readings.

After travellling at 110-120km/h for 20 min it reads 1min 45sec and stays there until I hit the 100km speed limit and slow down a bit. This brings the timer down to about 40-50 sec after 10 minutes or so, and stays there. When I hit the northern sububrbs and traffic lights, it continually drops, so by the time I get to the city it's between 3 to 10 sec.

So, I wouldn't bother waiting too long to let the turbo cool if you have been driving around the city. If you just let it idle while your getting things out of the car and then turn it off just before you close your doors, that should be enough. The only time I'd let it idle for a couple of minutes is when you're coming off the freeway to pick up fuel or food etc, or have been off road and done a lot of high reving just before you stopped.

AnswerID: 105719

Follow Up By: Member - Jeff M (WA) - Friday, Apr 08, 2005 at 13:27

Friday, Apr 08, 2005 at 13:27
Yup, I've fitted a Jaycar kit which has a temp sensor that I screwed into the exaust manifold heat sheild. Works a treat. Only activated if the shield is over 90c and goes for a maximum of 2 mins. It's amazing how well it works, if you tootle down the shops from cold it won't run on, if you thrash it down there it will. It's work quite well.
FollowupID: 362850

Reply By: Shaker - Friday, Apr 08, 2005 at 17:59

Friday, Apr 08, 2005 at 17:59
Don't walk away from your vehicle running on a turbo timer!

Unless you want to get booked!
AnswerID: 105757

Follow Up By: Member - Jeff M (WA) - Friday, Apr 08, 2005 at 19:26

Friday, Apr 08, 2005 at 19:26
Yeah I know the law too, but I've never EVER been even looked at whilst doing it and I've been doing it now for about 6 years. I've actually put a 10 minute override on mine and leave it going while I go into the shops to get the milk etc on a hot day so the air con keeps running, also good because it stops the "stop start" load on the batteries on those short trips.
FollowupID: 362894

Reply By: madlee - Friday, Apr 08, 2005 at 20:24

Friday, Apr 08, 2005 at 20:24
If you talk to a turbo shop they should tell you that you need to let it idle for awhile to cool down for this reason.It is to keep the coolant flowing through the turbo for it to cool down sufficently so the oil in the turbo doesn't boil dry,there for the bearings running dry.The harder you push the vehicle the hotter the turbo runs,the longer you idle for.Being a mechanic I have attended courses on the new turbo petrol cars and the Holden Astra turbo has 2 water pumps(one for normal operation),one electric pump that operates on shut down to keep the coolant flowing through the turbo for the above reason.So I would suggest idling for about 1 minute.All the best Peter.
AnswerID: 105783

Reply By: Hurricane - Friday, Apr 08, 2005 at 21:01

Friday, Apr 08, 2005 at 21:01
Thanks Everyone for the advice.

I feel bad now. For the last 2 weeks I have been just shutting the engine off. But most trips have only been under 20kms so far.

I will let my Turbo Cool down from now on.


AnswerID: 105790

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