Turbo cooldown period?

rickinAZ

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I think that we've generally consensed on below 400 degrees as a good target before shutting down the diesel. I've found that waiting isn't always easy. For example, today, after driving in traffic, I stopped to grab a take-out sandwich for lunch. When I parked, my turbo temperature was at about 550 so I left the Jeep idling, door locked, while I went in. It took a little longer than I thought (7-8 minutes) and when I returned the turbo temperature was at 397. That's a LONG time to wait. The ambient today is 95 degrees. If left to it's own devices, my turbo will drop all the way to 280 degrees even while idling, but after quite a while.

Am I the only one who is too impatient for 400 degrees? Is 400 degrees too aggressive a target?
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Gorilla57

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Rick, I mean absolutely no disrespect, but you worry too much. Ever since you've had the diesel, you've been on here worrying about this or that related to the diesel. Just drive the damn thing and enjoy it. The owners manual says when and for how long to let the motor idle before shutting down. Follow those guidelines and you'll be fine. I understand you are just trying to be the nicest owner to that motor/Jeep, but there is just too little time to worry about these small things. I'd love to buy used vehicles from you.....it would be in absolute pristine working condition. :like:
 
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rickinAZ

rickinAZ

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Rick, I mean absolutely no disrespect, but you worry too much. Ever since you've had the diesel, you've been on here worrying about this or that related to the diesel. Just drive the damn thing and enjoy it. The owners manual says when and for how long to let the motor idle before shutting down. Follow those guidelines and you'll be fine. I understand you are just trying to be the nicest owner to that motor/Jeep, but there is just too little time to worry about these small things. I'd love to buy used vehicles from you.....it would be in absolute pristine working condition. :like:
No disrespect taken at all - especially to well-intentioned feedback. As you've noticed, diesels are new to me, and I just want to make sure that I'm mechanically kind to my engine. You should see me when someone starts a dead cold engine and promptly runs it through the gears with redline shifts. :)

Good news is that the engine runs like a champ.
 

Plongson

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Wanna see me cringe?? My wife drives a Kia Stinger/twin turbo/12 sec street car...The frigg'n engineers have this thing programed when you start the engine, with ABSOLUTLY no input from the driver. it races the engine from zero rpm to 3000rpm for about 5 seconds. WTF!!

Talk about not waiting for oil pressure before running it up! I just don't get it...but there is nothing you can do about it...I drive a Jeep diesel LOL
 

Bulldog4xFour

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Rick, I mean absolutely no disrespect, but you worry too much. Ever since you've had the diesel, you've been on here worrying about this or that related to the diesel. Just drive the damn thing and enjoy it. The owners manual says when and for how long to let the motor idle before shutting down. Follow those guidelines and you'll be fine. I understand you are just trying to be the nicest owner to that motor/Jeep, but there is just too little time to worry about these small things. I'd love to buy used vehicles from you.....it would be in absolute pristine working condition. :like:
Yup, and its pretty short cool down times too, only like 30 seconds for city driving, 1 minute for highway, and 1 minute 30 seconds for heavy loads..
 

aaronrr

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As someone who's been looking at ecodiesels for a bit, I'm kind of shocked that they rely on this at the user level instead of having a system do this after shutdown. I've owned a ton of turbo vehicles in my life but perhaps it's specific to diesels.

Buying a $60k+ vehicle and then having to do this and monitor temps as a shutdown procedure just seems egregious and lazy.
 
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rickinAZ

rickinAZ

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Yup, and its pretty short cool down times too, only like 30 seconds for city driving, 1 minute for highway, and 1 minute 30 seconds for heavy loads..
I was driving in the city and it took 7 minutes to cool down from 550 to below 400 degrees. That said, I think that I'll try to follow Gorilla57's advice, and just follow the manual. But...I don't think that 30 seconds buys much temperature reduction in real world driving - at least not when it's pushing nearly 100 outside.

Does anyone's turbo temperature drop like a rock in 30 seconds time?
 

Gorilla57

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I was driving in the city and it took 7 minutes to cool down from 550 to below 400 degrees. That said, I think that I'll try to follow Gorilla57's advice, and just follow the manual. But...I don't think that 30 seconds buys much temperature reduction in real world driving - at least not when it's pushing nearly 100 outside.

Does anyone's turbo temperature drop like a rock in 30 seconds time?
When you idle to cool down, you are cooling down the turbo bearings, not the EGT’s. Saves from coking the oil in the bearings.
 

RoadiJeff

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I don't think there is a needed cool-down period for the turbo before turning the engine off. If there was, it would have been mentioned in the owner's manual. Also, any JL with the turbo would not have ESS because that is always turning it off and on.
 

Capricorn

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I was driving in the city and it took 7 minutes to cool down from 550 to below 400 degrees. That said, I think that I'll try to follow Gorilla57's advice, and just follow the manual. But...I don't think that 30 seconds buys much temperature reduction in real world driving - at least not when it's pushing nearly 100 outside.

Does anyone's turbo temperature drop like a rock in 30 seconds time?
Rick, 400F is just an unofficial estimate and should not be taken literally. Nothing bad will happen if you shut the engine at 450 EGT too. Synthetic oil won't coke so easily.
I wonder how many people are even aware of idling. I have many friends and colleagues at work who drive Ecodiesel Ram, Ford trucks with turbo diesel and they say they idle only after towing or after putting it on very heavy load. Some even did not even know there was such a thing and they had no issues even with years of ownership of their turbo diesels. But for day to day driving, they just shut off the engine as they think that driving for a few minutes sedately like in their subdivision or in the parking lot.

BTW, I also noticed that the TRB temps drop like a rock and cools much faster when the Jeep is in motion when you take your foot off the pedal for a few seconds - faster than idling. In your driving conditions, IMO you are ready to shut it off even if do some sedate driving for a minute or two before stopping and shutting it down.

While the turbo-diesel has this idling recommendation in the OM, I don't think the 2.0L doesn't even state that in the OM to idle.

I had a turbo Nissan Juke Nismo for many years and drove it for many years without even being aware of idling. And I drove that fun car with manual transmission like a sports car. I bought it new and sold it at 80K miles and had no issues.
 
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zgrw

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By the way, how do you check the temperature of the turbo? None of the gauges I look shows it.
 

Capricorn

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