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Discussion Starter #1
I noticed no posts about the cool-down periods for these engines? Are people not letting engines cool down/idle after driving them before shutting them off?

It's on page 149 of User Guide..
 

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I don't unless I am towing. I think for in town driving not huge grades there is no way we are overworking anything.

What I wonder with todays fancy computer engines is why we can't just park the truck and lock it and let computer decide when to turn it off based on temps it detects in the fluids etc. Really should not be that hard for them to figure out yet no manufacturer does this that I am aware of
 

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I think it says, regular driving, no load you should let it idle less than 30 seconds. I can get in the habit of that. I do understand that if I'm towing a load and pull off into a gas stop on the highway I should let it idle up to 5 minutes to let the fluids take the heat away from the turbo.
 

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Discussion Starter #4
The manual kinda wierd due to Highway, med load...
What about Highway, no load? Think I'll error on caution and let it idle for a couple of minutes after coming down off a highway before shutting it off so the turbo's can spin down and won't cook the oil..
 

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Didn't even know that you are supposed to do this. I can't see the engine really suffering if you don't. What's the worst possible scenario if you don't let the engine idle before shutting it off?
 

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It's a little chart in the Users Guide, on page 149 it doesn't even say why. Just calls it a turbo cool down chart.
 

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Discussion Starter #7
Turbo's on Diesel engine spin at high speed. If you don't let the Turbo's spin down and cool down you can cook your oil and cause Turbo failure. But since these engines are using Full SYNTHETIC oil you shouldn't need a cool down period. So, it's interesting why RAM wants you to observe a cool down period?
 

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Ram probably wants to "cover their butt". Turbo cool-down is universal with diesel engines. Kind of makes me wonder why the topic does not come up with gas engines???

I almost never "cool-down" in normal city/highway driving. Think the variable speed operation pulls the turbo down during operation. Now pulling on an interstate is a whole new thing. That turbo is most always spinning hard, fast and hot. For all my diesels over the past two decades, I would let them idle if I stopped at a rest stop or anywhere I stopped.

Even just a minute or so would be nice to let things settle out from a long, hot pull. Normally I lock the doors and leave the key in the ignition, engine running.

That's why we have insurance and I also know Samuel Colt.
 

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You will save fuel by letting them idle when stopping to pee or to get a drink. Its not good for a diesel to stop and start so fast. Plus it takes more fuel to get them started then to let them idle for 5 min.
 

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I have a egt pyro pre-turbo on my exhaust...having the AC on will jump the EGTs up 100 degrees. The Egr will also bump up the EGTs by 100 degrees (this is on a Cummins 6.7). Based upon my experience, I told my wife to keep the truck running with the a/c off for a minute before shutting down for her typical driving and based upon what I see. This should help lower the turbo temps to a safe level, it is basiclly in line with the chart in the manual.
 

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I have a egt pyro pre-turbo on my exhaust...having the AC on will jump the EGTs up 100 degrees. The Egr will also bump up the EGTs by 100 degrees (this is on a Cummins 6.7). Based upon my experience, I told my wife to keep the truck running with the a/c off for a minute before shutting down for her typical driving and based upon what I see. This should help lower the turbo temps to a safe level, it is basiclly in line with the chart in the manual.
that's a great thing to practice doing
 

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Idling these engines with that DPF/regeneration and DEF emission canisters still gives me the willies. One time I was hauling a huge military trailer to California and got stuck in Wyoming for a "week one day". Idled that thing for 22 straight hours.

It was idle or die in the below zero temperatures and snow. The Cummins literally did not use fuel. Swear that gauge dropped almost nothing. No emissions though on my '04.

Today's engines with that emission, just seem to do better running hot and sweaty. Sure hope idle time is not an invitation to trouble.
 

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I think it has more to do with the advancement of Turbo/Cooling technology than anything else. All the older Turbo cars called for a cool down period as well, yet now its virtually non existent.

Mind you it could come down to "education" as well.
 

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Getting an education. If older turbo cars needed a cooling period and then, over time, there were technological changes that negated that, why not the same for diesel?

To my knowledge, all the main diesel pickups recommend a turbo cool-down period.
 

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If I'm driving normal around town, I don't perform a cool down. In my experience with my gas turbo car, cool down occurs very quickly because there is not a lot of heat build up. Everything changes when I'm towing or coming off the highway. Then I allow some time for cool down.

In the old days with turbos that were not water cooled they would coke the oil since they (oil) did not tolerate excessive heat very well.
 

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Like shaker touched on I think it just comes down to typical use. A little turbo 4 banger will NEVER see the type of work, heat and punishment as these bigger rigs are subjected to, some of them on a daily basis. And yea the water cooled modern units are the real difference, however if you run a modern petrol turbo hard you would still need to cool it.

I've seen the turbos on STi's basically implode at Autocross because a cooling period was not observed between runs, mind you the man went run after run after run so he probably asked for it.
 

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It all comes down to use as abuse as Accused stated.

I used an IR Thermometer on my gasser turbo housing as a quick test a few years back. Granted, it was in the driveway with no load however the turbo housing did exceed 500F with the rpms up (and no airflow to help cool it from moving). As soon at I let off the throttle the temp started to decrease immediately and fairly quickly. Normal idle temps of the housing are 250F-300F. This is a PTE 6262 DBB water cooled turbo.
 

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So it is more of a precaution if you are working your truck particularly hard, or say its already really hot outside in the first place. It's not like you have to do this each and every time you finish driving.
 

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Discussion Starter #20
Around town stop and go traffic 30 sec cool down.
Coming off Highway run atleast 2 min cool down.
Pulling/towing at highway speeds 5 min cool down.

Yeah or Neah????


Owners manual has the cool down period recommendations...

My Ford F-150 with Ecoboost did not require a cool down period because the turbo's were water cooled.
 
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