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Old 7th August 2022, 14:08   #481
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Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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My source of knowledge is my profession. Being a marine engineer,
Good for you! Always nice to see another marine engineer on the forum. I spend the first ten years of my career in the merchant navy as marine engineer. Made it all the way to chief. Great education and experience!

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Old 9th November 2022, 14:43   #482
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Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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Very true. BMW's omission of a waiver from this 'feature' when the engine and turbo are very hot, is a very un-German thing to do . This is what the 330i Driver's Guide says.

There is no mention whatsoever of a hot turbocharger!
I read on bimmerpost that newer BMW's with the electric water pump circulate coolant for some time even after the engine is shut off. I'm not sure to what extend it is true.
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Old 9th November 2022, 15:03   #483
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Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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I read on bimmerpost that newer BMW's with the electric water pump circulate coolant for some time even after the engine is shut off. I'm not sure to what extend it is true.
Could well be. My Jaguar has an electric coolant pump for its supercharger and that runs after the engine is shut off.

On many cars the cooling fan, if electric which these days most are, the fan will run too, when the engine is shut off.

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Old 2nd September 2023, 13:41   #484
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Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

I am a firm believer in idleing engines at the start and when coming to a stop - especially after long high war drives, but interestingly manuals in new cars - like the Taigun say donít idle at the start and take off right away to conserve fuel!
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Old 7th September 2023, 00:36   #485
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Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

I had a habit of letting the engine warm up while stationary, but hadn't been practicing the cool down before shutting it off. Reading this thread to understand why this is important helped. Thanks!

I wanted to check with the fellow members here since I find the info in the manual for my Hexa XTA contradictory to what I have been practicing and what this thread suggests. The manual states that I should drive off immediately and specifically states that I shouldn't let the engine warm up while stationary.

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Old 7th September 2023, 11:30   #486
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Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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Originally Posted by apoorvpal View Post
I had a habit of letting the engine warm up while stationary, but hadn't been practicing the cool down before shutting it off. Reading this thread to understand why this is important helped. Thanks!

I wanted to check with the fellow members here since I find the info in the manual for my Hexa XTA contradictory to what I have been practicing and what this thread suggests. The manual states that I should drive off immediately and specifically states that I shouldn't let the engine warm up while stationary.

Attachment 2500232
This applies to all engines, petrol and diesel. This thread is primarily about idling the engine before shutting it down.

There are several reasons not to idle engine to warm it up. By far the most relevant one is poor cilinder and piston ring lubrication. As the engine is still relatively cold, oil doesnít adhere probably to the cilinder. It is one of the reasons cars that are used for short drives only often use more oil.

So always start and drive off, donít rev the engine and try not to load it till the engine is at proper operating temperature.

Also, modern engines, especially diesel, hardly warm up under idle to start with.
There are a few other issues as well, emissions are high as well. When the engine is cold.

As mentioned before this thread is about the need for idling your engine before shutting it down. Whether that is really necessary or makes any difference is in the eye of the beholder. As always, my advice would be to adhere to the manual and not the Internet. This practice is a bit of a carry over. Most turbo engines donít need to cool down anymore. Again, follow the manual, if it is necessary to idle your engine before shutting it down it will be mentioned in the owner manual. If it doesnít mention it, there is no need. You could still let it idle of course. It wonít do any good, but it wonít do any harm either. And it gives many turbo owners a nice fuzzy feeling they are taking good care of their beloved engine.

It is all in your owner manual!

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Old 7th September 2023, 11:44   #487
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Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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Originally Posted by Jeroen View Post
This thread is primarily about idling the engine before shutting it down.

There are several reasons not to idle engine to warm it up…
Thanks Jeroen! The Hexa also has a sticker on the driver's door which mentions that I should be idling the engine at the beginning and the end of the drive. From the two statements, it seems that I should be idling, but not while the vehicle is stationary? I wasn't able to figure out how that would affect the components though.

Image from TBHP's official review for the Hexa:

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Old 7th September 2023, 12:56   #488
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Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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Originally Posted by apoorvpal View Post
Thanks Jeroen! The Hexa also has a sticker on the driver's door which mentions that I should be idling the engine at the beginning and the end of the drive. From the two statements, it seems that I should be idling, but not while the vehicle is stationary. I wasn't able to figure out how that would affect the components though.
I think it is a very confusing sticker. What the hell is low idle speed?

Check what your owner manual says. The prolonged idling on start-up for turbo engines is likely to be to ensure proper oil flow through the turbo bearings. But on most modern engines that is not an issue. As soon as you start an engine the oil will be pumped all over the engine including the turbo bearings. There might be some correlation to ambient temperatures, especially very low (freezing) temperatures.

But again, I would go with the owner's manual recommendation.

On the upside: The sort of wear and tear you get during starting and stopping is very very very small. But it is cumulative, but it takes a long time before you would start noticing it, or would be cause for concern.

Think of it like this: This is a dedicated car forum. 99% of the average car owners out there have no clue. My wife would not know whether she drives a turbo engine or not. She is not going to adjust to anything like this. Like most people. And the public at large is likely to read owner manuals even less than the average petrolhead.

And still, tens or even hundreds of millions of turbocharged cars are driven without any problems every day, for billions of miles!!

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Old 7th September 2023, 13:28   #489
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Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

The owner's manual of Skoda Slavia clearly states to idle the engine for a minute before switching it off when the car/engine has been run at high loads. It is mentioned on page 68 & 69 of the Slavia owner's manual. However, it does not mention anything (to idle or not to idle) when the engine is started. Call me old school, I have been diligently practicing 60 to 90 seconds idling before & after every drive. Yes, the kind of satisfaction it gives is something which cannot be put in words
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Old 7th September 2023, 19:08   #490
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Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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Originally Posted by Jeroen View Post
I think it is a very confusing sticker. What the hell is low idle speed?

Check what your owner manual says...
While reading through the owner's manual, I also found that it recommends idling for 30 seconds on start, but all it mentions for the ending phase of the trip is that the engine shouldn't be shutdown while at high speeds (RPMs) and the a quick burst on the accelerator before shutting down does not serve any purpose and can possibly do more harm than good. It does not mention any idling before shutdown.

Looks like I can continue the idling just for peace of mind, but the manual seems to be more confusing than I had imagined.

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Last edited by graaja : 7th September 2023 at 19:24. Reason: Trimming quoted text. Please quote only a small or relevant part of a post
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