Idle Question

Kroni · Aug 17, 2020

Once again, I'm new to my 2018 2500 diesel. I've read a lot of members saying not to let the engine idle for long periods of time but everywhere I go I see guys letting their diesels idle. For example, at my local beverage barn nearly anyone with a gasoline engine turns off their engine and goes in but nearly every diesel owner leaves their engines running while they run in and then out. I see at the pumps too. The diesel guys always leave their engines running while re-fueling. I could go on but I think you get the idea. So what's the deal? Should I leave my diesel idling when I have a 5-10 minute errand or shut the engine down?

Or could I simply be observing guys with deleted and tuned engines? BTW, I'm bone stock.

Thanks

Sandevino · Aug 17, 2020

Don’t idle it “excessively”....

Older diesels (80’s and older) they were prone to harder starts due to thicker fuels and oils. The thought was it’s easier on the engine to keep it running and minimize stopping and starting. As technology improved, oils and fuels thinned, there became less reason to keep it running.

On modern diesels, there’s no reason to idle when stopped. You’re seeing the result of “personal choice” and doing what I’ve always done.

Kroni · Aug 17, 2020

Thanks for clearing that up. I guess I’ll shut’er down for those quick errands!

Gr8bawana · Aug 18, 2020

This and other diesel forums are full of "don't do this" stuff most of which is just internet BS.
Because someone's sister's boyfriends uncle's cousin claims to have had something happen to their truck because they did it 20 years ago. :mexsmoke:

crash68 · Aug 18, 2020

Kroni said:
. The diesel guys always leave their engines running while re-fueling. I could go on but I think you get the idea. So what's the deal? Should I leave my diesel idling when I have a 5-10 minute errand or shut the engine down?

Something else to take into consideration for idling, if your running the truck hard like towing or just highway speeds I'll give it a good solid five minutes (especially in the summer) to idle and cool down the turbo. If I am working the engine pull off the highway at a rest stop or fuel station I'll leave it idle especially when towing.
For normal driving if it's going to be a five minute or less stop I'll leave it idle, longer than that I shut it off.

Sandevino · Aug 18, 2020

My grand dad put it best...

Diesel is like a woman. It takes a while to get it warmed up. When it’s warm, run it hard. Hard as you can. When the work is done, let it (her or Diesel) cool down before working it again.

This is from an old farm boy from Italy, Tx...

Sherman Bird · Aug 18, 2020

Kroni said:
Once again, I'm new to my 2018 2500 diesel. I've read a lot of members saying not to let the engine idle for long periods of time but everywhere I go I see guys letting their diesels idle. For example, at my local beverage barn nearly anyone with a gasoline engine turns off their engine and goes in but nearly every diesel owner leaves their engines running while they run in and then out. I see at the pumps too. The diesel guys always leave their engines running while re-fueling. I could go on but I think you get the idea. So what's the deal? Should I leave my diesel idling when I have a 5-10 minute errand or shut the engine down?

Perhaps you should read the owners manual

Or could I simply be observing guys with deleted and tuned engines? BTW, I'm bone stock.

Thanks

crash68 · Aug 18, 2020

Sandevino said:
My grand dad put it best...

Diesel is like a woman. It takes a while to get it warmed up. When it’s warm, run it hard. Hard as you can. When the work is done, let it (her or Diesel) cool down before working it again.

I think he forgot the part about if something is smoking afterwards then your doing too fast.. :-D

Sandevino · Aug 18, 2020

crash68 said:
I think he forgot the part about if something is smoking afterwards then your doing too fast.. :-D

Grandma was in earshot when he said this. At 79 she said he’s never been fast enough to make anything smoke. She also said he drives slow.

Dennis Shellito · Aug 19, 2020

The Cummins in stock form that run the DPF exhaust is what shouldn't be left idling for extended periods. That is why the highway construction companies quit running Cummins pickups about ten years ago. They had to have them towed into the dealerships to have the exhaust filters cleaned or replaced, and they were warned not to idle them. On the other hand a deleted and tuned Cummins can idle till it runs out of fuel, though I don't recommend that either but for different reasons.

Sandevino · Aug 19, 2020

My dad switched his fleet (50 something trucks) in the concrete repair business from diesel to gas 7-8 years ago and hasn’t looked back. He got sick and tired of spending money on DPF issues and other BS problems. He still runs diesel class 3 and 4 trucks and tractors but they’re a different animal.

Gr8bawana · Aug 20, 2020

Dennis Shellito said:
The Cummins in stock form that run the DPF exhaust is what shouldn't be left idling for extended periods. That is why the highway construction companies quit running Cummins pickups about ten years ago. They had to have them towed into the dealerships to have the exhaust filters cleaned or replaced, and they were warned not to idle them. On the other hand a deleted and tuned Cummins can idle till it runs out of fuel, though I don't recommend that either but for different reasons.

Hmmm...is that why I see so many county trucks and animal control trucks that are CTD which idle for hours every day? The highway construction company my friend is a shop mechanic for runs nothing but CTD trucks and they also idle a lot.
NDOT has hundreds of these trucks as well and we all know how much these DOT "supervisors" like to sit in their trucks supervising from the a/c cooled trucks while idling.

Therottenjohnny · Nov 1, 2020

Dennis Shellito said:
The Cummins in stock form that run the DPF exhaust is what shouldn't be left idling for extended periods. That is why the highway construction companies quit running Cummins pickups about ten years ago. They had to have them towed into the dealerships to have the exhaust filters cleaned or replaced, and they were warned not to idle them. On the other hand a deleted and tuned Cummins can idle till it runs out of fuel, though I don't recommend that either but for different reasons.

Cn expound on the reasons why please? I have a 2013 2500 fully deleted that I left running last night to keep power to my camper I am towing. I had an electrical issue that I couldn't fix until morning. I checked on the vehicle this morning and no warning lights were on all the oil pressure. coolant temp etc were normal. But, I noticed coolant had dripped onto the ground. Not a huge amount but definitely noticeable. Any idea why? Thanks in advance.

Idle Question

Kroni

Member

Sandevino

Senior Member

Kroni

Member

Gr8bawana

Senior Member

crash68

ACME product engineer

Sandevino

Senior Member

Sherman Bird

Senior Member

crash68

ACME product engineer

Sandevino

Senior Member

Dennis Shellito

Senior Member

Sandevino

Senior Member

Gr8bawana

Senior Member

Therottenjohnny

Junior Member

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