Idling down - Feeling Stupid

[RedDawg]

PSA

I’ve read many times about letting your turbo “idle down”. I assumed this meant not to turn off your engine immediately. Let it idle for a few seconds before turning it off.

Nope. I experienced it today, and feel a bit stupid.

If you wait about 45 to 60 seconds after stopping and putting it in park, the engine noise changes. Your RPMs don’t, but you can hear the engine “idle down”.

Very important for the life of your turbos…….or so I heard.

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[Brian_B]

I have to admit, I haven't ever noticed what you are describing here. I always just do what you were originally assuming - just let the engine idle a bit if it's been run hard before I shut it off.

You sure it isn't something like the electric radiator fans spinning down, or HVAC? I can't think of any real reason the engine noise would change but the RPM does not change... the turbo certainly isn't doing anything different there.

 

[zyglyrox]

this hasn’t been a thing since the mid 2000s tbh, its not needed on anything remotely stock. bronco has an electric pumps to keep coolant & oil flowing through the turbo.

 

[SD-CA]

Actually, they don't have pumps operating after engine shutdown: "The EcoBoost engine uses passive thermal siphoning for water cooling,” Plagens explains. “During normal engine operation, the engine’s water pump cycles coolant through the center bearing. After engine shutdown renders the water pump inactive, the coolant flow reverses. Coolant heats up and flows away from the turbocharger water jacket, pulling fresh, cool coolant in behind. This highly effective coolant process is completely silent to the driver, continuing to protect the turbocharger.”

https://thebronconation.com/general...-down-before-shutting-the-vehicle-off-t.3288/

 

[RedDawg]

this hasn’t been a thing since the mid 2000s tbh, its not needed on anything remotely stock. bronco has an electric pumps to keep coolant & oil flowing through the turbo.

What’s the change I’m hearing? The engine gets significantly quieter after idling for a minute.

 

[CalvinT]

PSA

I’ve read many times about letting your turbo “idle down”. I assumed this meant not to turn off your engine immediately. Let it idle for a few seconds before turning it off.

Nope. I experienced it today, and feel a bit stupid.

If you wait about 45 to 60 seconds after stopping and putting it in park, the engine noise changes. Your RPMs don’t, but you can hear the engine “idle down”.

Very important for the life of your turbos…….or so I heard.

years ago I had a Mitsubishi turbo diesel pickup that required letting it idle for 30 seconds so the turbo could cool off. But the bearing wasn't water cooled. My WRX has no such restriction, the the turbo bearing is water cooled. The coolant around the bearing actually boils at first and is replaced by fresh coolant until the bearing cools down.

I agree it's probably not a good idea to shut it down right away, but let the engine idle for a few seconds. Horses are like people, they need to cool a bit after exercise.

 

[ducksface]

If the cool down was a thing(and ford says it isn't) wouldn't the aftermarket sell an auxiliary timed water pump like our current auxiliary water pump?

Even though ford says it's not a thing, why isn’t the aftermarket feeding on the fears incited by some folks?

Why isn't this being addressed?

 

[RedDawg]

So y’all are saying it’s not important to let the engine idle until it hits that decreased idle noise?

What is that change? A minute after putting it in park, there’s a significant shift in the idle. Why??

 

[Dan-O]

So y’all are saying it’s not important to let the engine idle until it hits that decreased idle noise?

What is that change? A minute after putting it in park, there’s a significant shift in the idle. Why??

Take a video with sound and post it here

 

[Jakob1972]

I Come from the old school diesel world. I always let the 12v in my F250 cool before I shut it down, just carry it over to all my vehicles, now that they are all turbos except my NA Cobalt but I let that cool too, 400k must be doing something right.

 

[BroncocnorB]

I pull into my garage and turn off the engine. Then I go into the house. If I need to be idling in my garage that’s a whole other issue I won’t get into.

 

[BroncoChallenger]

So y’all are saying it’s not important to let the engine idle until it hits that decreased idle noise?

What is that change? A minute after putting it in park, there’s a significant shift in the idle. Why??

It is likely the cooling fan changing speed because the engine temp has dropped sufficiently that it doesn't need to be running maxxed out.

Idle down is something that comes from the old diesel world where turbos were cooled by engine oil, not coolant. The idea was to let the engine idle for a few minutes, to let cooler oil get up and through the turbo and take away some of the heat. With the system in the Bronco, it's not necessary, but it certainly doesn't hurt anything, especially if you've been running it hard.

If I've been on the road pulling a decent load, I will let my truck sit and idle for a minute or two before I shut it down. It may not be helping, but I don't see how letting it cool a little longer is going to hurt anything either.

 

[Valhalla]

It is likely the cooling fan changing speed because the engine temp has dropped sufficiently that it doesn't need to be running maxxed out.

Idle down is something that comes from the old diesel world where turbos were cooled by engine oil, not coolant. The idea was to let the engine idle for a few minutes, to let cooler oil get up and through the turbo and take away some of the heat. With the system in the Bronco, it's not necessary, but it certainly doesn't hurt anything, especially if you've been running it hard.

If I've been on the road pulling a decent load, I will let my truck sit and idle for a minute or two before I shut it down. It may not be helping, but I don't see how letting it cool a little longer is going to hurt anything either.

This

 

[RedDawg]

It is likely the cooling fan changing speed because the engine temp has dropped sufficiently that it doesn't need to be running maxxed out.

Idle down is something that comes from the old diesel world where turbos were cooled by engine oil, not coolant. The idea was to let the engine idle for a few minutes, to let cooler oil get up and through the turbo and take away some of the heat. With the system in the Bronco, it's not necessary, but it certainly doesn't hurt anything, especially if you've been running it hard.

If I've been on the road pulling a decent load, I will let my truck sit and idle for a minute or two before I shut it down. It may not be helping, but I don't see how letting it cool a little longer is going to hurt anything either.

Thanks!

 

[Roger123]

I'd say cooling fans as well, they are ridiculously noisy on Bronco. Are you turning off your AC when you notice the change?

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