After driving let engine run to cool turbo

[KEG2021]

Thoughts…letting the engine run 10-15 minutes after driving to let the turbo cool down?

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[kevman65]

It is a good idea to let a turbo diesel engine cool, yes.
10-15 minutes may be a bit long.
My cast iron V-8 turbo diesels usually returned to normal EGT in about 5 minutes.

 

[Mac]

The turbo is cooled by the coolant and oil so idling shouldn’t be needed to cool it down.

 

[dcmdon]

I've been driving turbocharged cars for decades. (1983) I was also a technician at a Saab dealer. (The 1977 Saab 99 turbo was the second production car to ever use a turbocharger. My dad purchased an ex-Saab factory rally 99 Turbo in 1979 - talk about lag. wow).

Let me give you a history lesson.

Back in the bad old days. Turbos bearings were oil cooled. If you shut off the car after running it hard, the hot exhaust side turbine would heat soak into the bearings; heating the oil until it burned, something called coking. You would basically fill the machined in journals supplied the bearings with oil, with carbon.

Coking would eventually clog of the oil journals which starved the bearings of oil until they failed.

The way to avoid it was to let the car idle for a few minutes before turning them off. In fact there was a product called a "turbo timer" that Ii had on one of my 900s that ran the car at idle for 5 minutes after I shut it off and locked it. So I didn't have to wait.

Then in the 90s cars started using water cooled turbos. This wrapped a jacket of cooling water around the bearings in addition to the oil. Water soaked up the heat and through localized boiling made sure that coking was a thing of the past.

Since then you haven't had to let a car cool down.

I dont' know how this Fiat engine is designed, but I will tell you that if you run full synthetic oil (always a good thing with a turbo engine because of reduced coking) and have a water cooled turnbocharger, then you don't need to let it idle down.

Even then its always a good idea to try to stay out of the boost for the last couple of minutes of your drive.

I hope this helps.

 

[shrinkhead]

they sell cars in 2021 that require you to let the engine idle for 15 minutes after driving them ? really ?

 

[Choatecav]

Thoughts…letting the engine run 10-15 minutes after driving to let the turbo cool down?

While you will have to let a turbocharged diesel cool for a few minutes, 10 - 15 is too long. Having owned several turbocharged diesel truck I know first hand that cooling down if you have run it hard is important.
You need to install a pyrometer gauge which will show you the temp coming out of the intake manifold. I usually let it get to about 300 before I shut if off.

 

[Jefe1018]

Here is page 154 of the owner’s manual, FWIW. Page 153 advises against excessive idling.

 

[Mtpisgah]

same reply from my days of driving my Saab or my wife’s WRX…any modern car is going to be designed to run a fan at shutoff it engine cooling is needed.

 

[WXman]

I monitor turbo temps with my Scan Gauge II on the dash. It doesn't take long at all for the turbo to drop below 400F once you park. 30 seconds will do the trick unless you've been towing heavy or the weather is insanely hot.

 

[Mac]

While you will have to let a turbocharged diesel cool for a few minutes, 10 - 15 is too long. Having owned several turbocharged diesel truck I know first hand that cooling down if you have run it hard is important.
You need to install a pyrometer gauge which will show you the temp coming out of the intake manifold. I usually let it get to about 300 before I shut if off.

Pyrometer measures the temp on the exhaust side either pre or post turbo has nothing to do with the intake manifold. I ran a modified Dodge with a 5.9 for a while, even after running hard 2 or 3 minutes tops and it was as cool as it was going to get and it was only oil cooled.

 

[Trickster]

To answer the OP question, no.
A short 2-3 minutes if you have been towing, hard on the throttle for a bit before shutdown or driving in mountainous terrain.
But for everyday normal driving, I wouldn’t worry about it.

 

[Gladman]

I just use the EO temp gauge in the Off Road [ages and make sure the oil is under 100 C before shutting down. if not, say the oil is 105 C it usually only takes 1-1.5 minutes to cool under 100.

 

[Aonarch]

It's a modern vehicle. Just drive it normally.

 

[Trickster]

It's a modern vehicle. Just drive it normally.

Define normal?
?

 

[Aonarch]

Define normal?
?

Drive it like you stole it?

Well maybe not this engine...

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