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Discussion Starter · #1 ·
This Ram 3.0L will be my first diesel so obviously I don't want to shorten it's lifespan. The diesel manual (downloaded) includes a chart showing the number of minutes to let the engine idle before shutdown. How important is this? Is this just a good idea in the long run or should we expect mechanical issues right away? Sounds a bit nit picky to me but never owned one before. What about short trips (5 min) to the store or work? Probably not enough time to warm up completely so probably don't worry about a 'cool down'?
 

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If is not really hot I do not worry about it. I have 205000 miles on my 2004 and never had any issues. I have been doing the same with my 2014 ED. Only if it is really hot or after towing then let it cool down a bit.
 

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others will have a different opinion and I'm not going to say they are wrong but I have never let my diesel cool down at idle. last diesel had 200,000 trouble free miles. maybe it will at 225,000 and letting it idle would take it to 250,000??? if I'm towing I figure the time it takes me to get off the highway down the road into a parking lot find a spot is enough time for me.
 

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Discussion Starter · #4 ·
Thanks for experienced opinions. Sounds like just with normal driving we wont worry about. I would like to drive this truck for many years!
 

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On my 18-wheeler, it says to let it warm up 3-5 minutes and cool down 3-5 minutes. Some other truckers think I'm crazy for going by the manual because they're stuck in the seventies with their mentality. My big truck is a 2010 and has much newer technology than any of the people I work with, so I go by the manual and even went with a buddy to the Cummins shop and asked the manager. Manager kinda made a face, but said it's good to go when then idle drops down. In most cases, that's only a minute on my truck. So I just do my paperwork then go. When I get back, I do my paperwork and shut it down.

Others have said that the time it takes to back an 18-wheeler into its parking spot is enough for the turbo to cool down. It usually takes at least a couple of minutes, so I agree with that.

I would expect the same principles to apply to the 3.0. What happens when you don't warm up enough--even in my car I take it easy for a couple of miles--then the valve springs don't warm up enough and can be a bit brittle. Also, it takes a minute or two for the oil to make its way throughout the engine after all draining into the pan overnight.

Upon parking, the problem is heat again. The turbo is hot. And so is the oil that is lubricating it. If you don't idle, some of the oil will sit there in the absolute hottest part of the engine and may cake/flake/become sludge.

So, just don't go crazy after ANY VEHICLE has been sitting for many hours and allow it time to lubricate and warm all of the internals. And in a vehicle with a turbo, let it cool down--just like an athlete.
 

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Diesel exhaust gas temps (EGT) are directly linked to how hard the engine is working, not necessarily how fast it is spinning. I used to operate large diesel generators before I retired (they use turbocharged GM locomotive engines, V-16 about 20 feet long) . The engines ran at constant speed - 900 rpm's, you could watch the EGT rise as fast as the generator was loaded and fall just as quickly when the generator was unloaded. The EGT is what is adding the heat to the turbo on our ED's. So the point of all this is that the turbo does need some time to cool down after the load has been removed from the engine. If you were traveling empty at 70 mph on a flat interstate getting 28 mpg, you'll probably be cooled enough by the time you pull off the exit and park the truck. On the other hand, if you're hauling 7,000 pounds up a long grade and you pull into the rest area at the top of the hill, you should allow the turbo to cool for the 3-5 minutes recommended in the manual. IMO
 
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Too bad there isn't a turbo temperature gauge that you could monitor to determine when to shut it down. Can you use the coolant or oil temperature as a guide? Or do they cool down too slowly? At least those temperatures wouldn't be so subjective.
 

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You got some great advice. Read and remember.

That's my advice. Me??? I only cool down when it's been super hot and taxed while towing. Most all other times I forget.
 

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Discussion Starter · #9 ·
Yeah, a gauge would be handy. Probably end up letting it run while filling up only if it has been worked hard on the road. It should have a nice sounding idle too!
 

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If you Google "diesel cooldown timers" you'll see several aftermarket kits are available. Some are simple timers that keep the engine running for a set time after you shut it off. More elaborate units actually monitor EGT's with a probe and will shut the engine down when EGT's drop below a set temperature like 350-400 degrees or if a time limit is reached. I have no personal experience with any of these units, and have never felt the need to buy one. But I've only been driving diesel pick ups since 2005.
 

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If I'm accelerating hard or under load (climbing a hill) right before shut down, I idle for 1-2min. If coasting during last couple min of driving, I feel that the turbo hasn't spooled up much. I wouldn't go by engine temp. Even if engine still cold, I bet those turbo bearings could beat up quickly when spinning tens of thousands of RPMs.
 

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With our 5.9 and 6.7 Cummins and 7.3 Powerstrokes the turbo's cool down very quickly when not towing. My truck will drop to around 300 degrees in less than 30 seconds. Towing on the other hand will take much longer to cool down. I have seen my truck take over 5 minutes to cool down after hard towing coming off a freeway.

High idle feature should be a must. Makes the cool down faster and even the warmups faster.
 

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I also use my unconnect phone app to start and shut down while away from the truck. I love the flexibility the remote starter provides with phone integration.
When you use the remote shutdown, do you just leave the key in the ignition or do you have the push button start?
 
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