Shut Down

[vagabond]

Hi all, I am new to the forum and have gained much information. One thing I find myself doing is pulling in for fuel or the store and just shutting it off. I sometimes tow so I just got gauges and can see I am shutting down anywhere between 400 to 650 on the pyrometer. Please advise what kind of damage I am going to cause or what I should look for if I have already caused some. I have the 04. 5 with Auto Thanks

vagabond

 

[GFritsch]

I leave mine running while fueling. Never waited to shut down at 200k miles on 94. Never a problem--but I don't tow anything heavy. I think I might get a shut down timer on the new one. There is a recent thread talking about shut down times. The moral of the story seemed to be turn off the Air cond and it will cool down much faster. I think there is a shut down unit that shuts down after temp drops.

 

[EEngel]

Shut down timer

GFritsch,



I added the shut-down timer to my new truck and I just love it. I took the push button / led / switch out of the box and mounted it near the 4 wheel drive shifter. It's a nice clean look.



I let the truck run while I fill, then hit the 4 minutes on the timer, lock my doors, go in and pay, come out and the truck is still running.

 

[Blakers]

Let it get down to 300 or 350 before shutting down. Like GFritsch said, I would not even bother to shut down for a quick fuel stop. Letting it idle awhile allows everything to coold down nice.



I don't know why the manufacturer does not stress more strongly the need to let these engines cool down after long pulls. I know they mention it in the book, but they should print it right on the dash.

 

[vagabond]

Thank you for the info. Could you please let me know where I can purchase a shut down timer. Also what damage might I have done? Thanks again

 

[rbattelle]

The damage that you might incur from hot shutdowns is in the turbo. Coking temperature of the oil is around 300 degrees. If your turbo is at 600 degrees and you shut it down, the oil stops circulating. Then the oil that's in the bearing compartment literally cooks under the heat and turns to carbon. Damage occurs when you re-start the engine: there's no lubrication (for the most part) on the turbo bearings, so they run with very high friction for a few seconds (until fresh oil circulates in). Over time, this can destroy the turbo bearings.

 

[RankRam]

Originally posted by vagabond

Thank you for the info. Could you please let me know where I can purchase a shut down timer. Also what damage might I have done? Thanks again

Here ya go! www.cool-downtimer.com

 

[SOLER]

I agree with all that's been said. I tend to leave mine running while fueling, especially when I've just been pulling.



One thing I do, however, if I know that I'll be wanting to shut down soon, is drive in a lower gear just before pulling in. For instance, if I see my exit coming up and am going in to fuel, or whatever, I shift down into 5th, and get the RPMs up to around 2500 with little load, and therefore little or no boost. This helps bring the egt's down real quick. This also gets the fan turning faster. If you were working it hard, then the fan clutch will be engaged, and the higher RPMs, combined with no load, cool the whole engine down nicely.



SOLER

 

[GFritsch]

Vagabond, do a search for cool down timers. Steve St. Laurent talked about one that shut down by temp. Sounds like the way to go. I highly doubt that you have hurt your truck. Don't worry. These motors/turbos are very hearty.

 

[klenger]

Here's my theory on this: I am of the understanding that the reason for the cool down period is to prevent cokeing caused by the COOLING of hot oil in the turbo bearings. Note that it is not the presence of hot oil in the turbo, but COOLING of the oil that causes the cokeing. Unless I have been towing or running hard, I usually do not do a cool down for stops for fuel because the oil doesn't have a chance to cool down in the turbo anyway. In a few minutes, I start it up again, the oil is circulating again, and away I go. I also do not usually do any cool down when arriving at my destination (unless towing, etc. ) because the last few blocks are usually at very low power anyway. I don't have an EGT gauge (yet). I've been watching this forum for over 3 years and have never heard of anyone wasting a turbo or pistons on a stock truck from high EGT's.



In general, it seems that we spend much of our time here discussing the best oil, controlling EGT's, fuel additive, etc. , when in reality, it seems that there is very little evidence that any of these factors have any significant difference in engine reliability. This comment is not meant to flame anyone or any subject. I enjoy this discussions and have my own preferences just like everyone else. It just seems that there is very little evidence that any of it really makes any difference.



Light 'em up: #ad

 

[cArNiVaLwOrKeR]

I let her run for 1 minute...

IMO thats enuf, dont have gauges YET!!!

 

[Jeremiah]

Cool-down

A veep with a Cummins shop said don't worry too much about turbo melt-down on the newer engines unless you're pulling heavy over Eisenhower west of Denver and decide to pull over real quick and shut it down. Then he said you might let it idle for a couple of minutes.



Hey, don't shoot the messenger ... just passing along what someone who knows these engines frontward and backward said at a diesel workshop.