"Long Periods of Idling is Acceptable" says Dodge Engineer

[HBarlow]

A couple of weeks ago another member started a thread in this forum asking about idling our 6. 7 Cummins engines for long periods of time. Everyone who replied including myself probably had the opinion that it was not okay. We've all heard it and we've all probably repeated it as the "gospel. "

Fellow member Shelby Griggs surprised me when he posted a quote in that thread a couple weeks ago from the Dodge.com website Body Builder's Section stating that it was okay to idle the new 4500/5500 cab and chassis trucks on a jobsite for as long as needed because the new engines meet ARB standards which permit long period of idling. The Dodge Body Builder website statement went on to compare the Dodge to it's inferior competitors, GM and Ferd, and state that owners of similar GM and Ferd trucks could not idle their trucks because they don't meet ARB standards and it was violated smog standards and the law. When I read this I thought, "what about 3500 cab and chassis trucks?" We all know that the 3500 uses engine and emissions equipment identical to the 4500/5500.

I sent an e-mail to Dodge.com custormer service not expecting much. They acknowledged my question immediately and promised a reply. A week went by and yesterday I got a reply via e-mail which suggested I ask the Dodge Body Builder Section's Customer Service center. Here is the message I received:

Dear Harvey:

Thank you for your recent inquiry.

Upon further research, your questions would be best answered by Dodge
Body Builder's Guide Customer Service. This department can be reached at
1-866-205-4102 from 6:00 AM until 2:45 PM. It is a voice mail system,
simply leave a message detailing your question and leaving your contact
information. "

And here is my original message:

Original Message Follows:
------------------------

New Vehicle Information - Dodge Brand Site
Brief Description:
Can I idle the Cummins engine in my 2008 Dodge Ram 3500 Cab and Chassis
for long periods of time?

Comments:
I discovered the following paragraph on the Dodge website: "Jobsite idling Dodge Ram 4500 and 5500 Chassis Cabs have low enough emissions that they can idle indefinitely at a jobsite, letting you use their HVAC and electrical features. This is because Dodge Ram 4500 and 5500 Chassis
Cabs meet the 2008 Air Resource Board's state diesel emissions standards for medium-duty trucks (which includes CA, CT, DE, GA, ME, NJ, NY, NC, PA and TX). So you can let your truck idle while Ford and GM owners have to automatically shut down after idling five minutes or risk fines in these states. "

I am the satisfied owner of a 2008 Dodge Ram Quad Cab and Chassis. It has been my understanding that the engines, transmissions, and emissions equipment of the 3500 cab and chassis trucks are identical to the 4500/5500 cab and chassis trucks mentioned in the statement on the Dodge website. My question: Does the permitted idle statement also apply to my '08 3500 cab and chassis? Or stated another way, without regard to ARB standards, is it permissible from the perspective of potential soot accumulation in my diesel particulate filter and turbocharger to idle my 3500 for long periods of time also? Thanks for your assistance.
Harvey Barlow

I called the number provided and left a message with my question. Later this morning I received a call from a very professional, very helpful engineer. I repeated my question and he explained that they wrote the paragraph about idling 4500/5500s only because the idle laws apply ONLY to medium duty and heavy duty trucks. He said owners can idle a 3500 C&C as long as we like. I told him I assumed that the Dodge engineers had thoroughly considered the risk of sooting up our turbos and/or dpfs. He assured me they had.

We talked for about 15 minutes and he answered all my questions.

In summary he stated clearly and without any ambiguity whatsoever that owners of cab and chassis trucks and pickups can idle their trucks as long as they wish. He specifically stated we can idle them all day or all night if we want to. I asked if it should be at low idle or high idle. He stated clearly again, "it doesn't matter. "

He told me that the regen system has two modes. I'm having trouble remembering the details but I think he said one mode will allow the engine to idle for long periods of time without adding additional soot to the dpf and the other mode will kick the regen up a notch (my words) and reduce any accumulated soot.

I asked the engineer if he was familiar with TDR. He replied, "of course. " I asked him if he minded if I posted the reply he provided for the information of all TDR members. He said no, go ahead. I asked him if it was okay to publish the Body Builder Guide Customer Service telephone number. Again he told me it was okay but he wanted me to emphasize that the Body Builder website and phone number are primarly intended to deal with cab and chassis trucks and issues related to upfitter bodies. He did say though that they will also answer engine questions regarding C&C trucks.

I asked him if a source of written explanation was available to anyone who wanted to read and learn more about the new engines, emission systems, and proper operation. His reply was polite and tactful but basically his answer was that Cummins, who designs and builds the engines and systems, wants them to be "transparent to the owner/driver. " In other words, according to him, Cummins thinks we don't need to have detailed knowledge of how the systems work in order to drive and use the engine properly. He didn't say this but I suspect Cummins and Dodge don't want us to know any more. It is probably information they don't want their competitors to have access to and probably don't want us TDR members/Dodge owners to know enough to try to tinker with them. I accept this.

If anyone wants to know more about your C&C truck I would suggest you call. Please don't bombard them with 30,000 questions in the next few weeks and cause them to tune us out but Dodge Body Builder's Section are friendly, helpful folks who are very helpful and willing to give us good answers to reasonable questions.

 

[Shelby Griggs]

Thanks for posting this Harvey! This is hard to believe in light of all the threads stating the new trucks need to be driven like you stole them! Very interesting indeed. One thing holding me back on a new truck is the sooting problem, I idle my truck (by Dodge's definition) quite a bit, since most off road low speed driving tends to be at low EGT's. In my job there are quite a few hours of low speed driving, opening gates, etc. where the EGT's remain low, I simply can't drive like I stole it ALL of the time. Sounds like Dodge/Cummins is getting a handle on the emissions part of the package.



I will probably just wait for the 4th Gen's now, hopefully the economy will be picking up and what few bugs are left in the emission system will be worked out. Sure are some good prices on 08's out there right now though!



SHG

 

[fox]

I'd say trust the Cummins engineer, and keep it to 3-5 minutes!!!

 

[sag2]

He told me that the regen system has two modes. I'm having trouble remembering the details but I think he said one mode will allow the engine to idle for long periods of time without adding additional soot to the dpf and the other mode will kick the regen up a notch (my words) and reduce any accumulated soot.

The newest flashes incorporate (IIRC "net zero") mode that maintains or reduces the soot load in the DPF. What that means is the calibration will keep the soot load at an acceptable level and if it does climb too high (above about 47 grams on the scan tool) it will raise the idle, go into engine braking to build engine load, and possibly provide after injection to build heat to burn soot faster than it is generated. Extended idle after about 30 minutes should trigger a noticeable change in engine speed or exhaust tone indicating the soot reducing mode is active. Keep in mind every truck is going to be different because every truck has differing starting soot load at any point in time.

Also note this will keep the DPF from becoming full, but soot is being generated at all times the engine is running and EGR is active at idle, so soot is still entering and being deposited in the intake system and turbo before it gets to the DPF.

 

[jimnance]

I'd say trust the Cummins engineer, and keep it to 3-5 minutes!!!

I'm with you Fox. Sounds like marketing hype to me. I'd like to hear it from Cummins.

 

[Bill Lins]

It was always my understanding that idling for long periods let the cylinder temps fall enough that all of the fuel wouldn't burn, but would "wash down" the bore. Is that not (or no longer) true?

 

[HBarlow]

It was always my understanding that idling for long periods let the cylinder temps fall enough that all of the fuel wouldn't burn, but would "wash down" the bore. Is that not (or no longer) true?

In my opinion, having used a set of gauges on all three Dodges I've owned, exhaust gas temp does in fact cool down after a few minutes of idle and probably allows unburned fuel to wash down cylinder walls and add fuel to the crankcase oil. I've always used the high idle (or exhaust brake in my '01) when iding for long periods and will continue to do so.

 

[Coalsmoke]

Food for thought...

Harvey, was the focus of your discussion with Dodge on the emissions system or cylinder washdown?



It sounds to me from reading the threads that the emphasis has been on the emissions stuff and making sure it is not harmed from extended idling, which is important in its own right, but to me the primary concern would be cylinder wash down. Right now, in temps about 5-10* above freezing, on low idle my truck very quickly drops to a EGT of 210-220* F, which is much too low for my comfort. In earlier engines it's accepted knowledge that a person needs at a minimum 300*F EGTs (pre-turbo) to ensure that the cylinder temps will stay high enough to ensure proper combustion. However, with the different rings in the 6. 7 engines I am wondering if cylinder wash down has been addressed. With this in mind, its easy to see that as far as Dodge is concerned the truck will be fine because their emissions equipment will continue to function normally, but as far as Cummins is concerned, extended idling is causing accelerated wear through incomplete cylinder combustion and the resulting cylinder wash down.

 

[JMetzger]

I think I would go with what Cummins say's rather then what Dodge say's. Cummins built the engine.

 

[CUMMINZ]

While in Winston-Salem, NC (Walkertown) I visited the auto/truck unloading facility (off RR cars). My son & I saw a new 4500 that had a logo on the side of it that stated something like "OK for extended idle". Those were not the exact words.

 

[Mhannink]

well if dodge is suppling the warrenty they can't make you pay if they have to replace an engine when they say you can idle for long periods of time.



of course this may not stop them from trying

 

[Coalsmoke]

No, but you take a 12-15 year before overhaul engine and reduce it to a 6 year engine from cyl wash down and you will be the one left paying for it once its outside of the warranty window.

 

[Bob4x4]

There are indeed many factors to take into consideration here.

# 1 in my mind is the engineers that are telling you it is ok also said the 6. 7 was ready to go to market. How many software updates and tsb's has it taken to get to where we are now?The theory of how something should work is often a bit different from what really happens. Also remember the C/C is a different pkg from the pick-ups.

In the end it is still up to the end user to make the best choice for his needs and to deal with what may or may not happen down the road.

Good luck to all the 6. 7 owners



Bob

 

[HBarlow]

Harvey, was the focus of your discussion with Dodge on the emissions system or cylinder washdown?

It sounds to me from reading the threads that the emphasis has been on the emissions stuff and making sure it is not harmed from extended idling, which is important in its own right, but to me the primary concern would be cylinder wash down. Right now, in temps about 5-10* above freezing, on low idle my truck very quickly drops to a EGT of 210-220* F, which is much too low for my comfort. In earlier engines it's accepted knowledge that a person needs at a minimum 300*F EGTs (pre-turbo) to ensure that the cylinder temps will stay high enough to ensure proper combustion. However, with the different rings in the 6. 7 engines I am wondering if cylinder wash down has been addressed. With this in mind, its easy to see that as far as Dodge is concerned the truck will be fine because their emissions equipment will continue to function normally, but as far as Cummins is concerned, extended idling is causing accelerated wear through incomplete cylinder combustion and the resulting cylinder wash down.

Coalsmoke,

The point of the paragraph on the Dodge "Body Builder Website" stating that it was okay to idle the trucks for long periods, as I understood it, was about emissions and emissions laws/regulations.

However, I specifically asked the engineer I was speaking with if they had carefully considered the effect extended idling might have on soot buildup in the turbo or dpf. He assured me they had and expressed confidence that it would not cause harm to the engine.

I did not specifically inquire about cylinder washdown and I didn't want to continue "interrogating" the man who had taken time to extend me a courtesy and answer my questions. I also didn't want to imply a lack of trust. I am skeptical by nature and usually quick to pickup on bs when someone is evasive or trying to fool me. I did not get the impression the man I was speaking with was evasive or was only telling me part of the story.

All these questions are good and valid but I think we should keep in mind, Dodge provides the warranty and pays warranty repair costs. We are also all on the same team. It is in the best interests of Dodge people to make sure to the best of their ability that their products please us and give us good service life. They are not out to cheat us.

I think it would be appropriate of others to write and forward polite inquiries to the Dodge website asking further questions including "how about cylinder washdown" that might result from extended idle.

 

[Bob4x4]

well if dodge is suppling the warrenty they can't make you pay if they have to replace an engine when they say you can idle for long periods of time.



of course this may not stop them from trying

The engineer that said you can idle forever is not the guy that ok's the warranty repair:-laf:-laf



Bob

 

[HBarlow]

I understand the uncertainty felt by some members regarding any possible harm or shortening of the service life of their engines that might be caused by extended idling. I don't know what is right but have confidence that the Dodge engineer was telling me what he believed to be true and accurate.

I have allowed all three of my Dodges including the new 6. 7 to idle but always used the exhaust brake or high idle feature to keep combustion temps as high as possible and to avoid or reduce any unburned fuel washdown.

OTR truck engines have idled for long hours every day of their lives until recent emissions laws began to try to restrict the practice in some locales. Most of the time they don't even use fast idle. Does this cause harm or reduce service life? I don't know but doubt it.

One thing I have learned in over seven years of Dodge-Cummins ownership and TDR membership is not all the information that is believed as gospel and routinely passed around is based on truth.

The "drove it like you stole it" is a phrase that comes to mind. We have all accepted it and passed it on but as I think about it, I don't remember reading it in the owner's manuals of my Dodges or in the ISB 5. 9 Operator's Manual I bought from Cummins. Is it actually the practice cummins wants us to follow? I don't know.

 

[CUMMINZ]

The truck I saw in Winston was a chassis cab. That is the 305 HP engine and was labeled for the long idle. Maybe they have made a few minor tuning changes.

 

[Travis_Ray]

I don't own a 6. 7 so I can't really say much, but I did have a dodge tech tell me that when it comes to warranty repair, they check to see how much time the truck has logged at idle, and if more than 20% of of your time is spent at idle, your warranty is void.

I know the 5. 9, and I would doubt that the 6. 7 was built to be different, run better when hot. Cummins rebuilt my engine and told me to drive it hard but don't run the complete dog snot out of it. I'm sure that would be their mentality on the 6. 7, but it's hard to tell since no cummins service centers that I personally know of will touch a 6. 7.

 

[pcarlson]

I've heard the 20% before and since I don't own the 3rd Gen can someone post the warranty disclaimer stating the restricted idling time of any percentage? Unless it is written in your book or sent to you as a supplement I would say they don't have a leg to stand on in denying warranty.



I know quite a few plumbers, electricians, and carpenters who idle all day everyday and have had zero problems with the truck and or warranty.



Where I work you could probably look at the CAT C15's and 13's and say that CAT built them so they are just like all the rest but that would be an incorrect assumption. They are built to our engineering specifications not CAT's. I would suggest that we consider that the 6. 7 is built to Dodges specifications and differ from other Cummins 6. 7's.

 

[Russknh]

Let me see if I can shed a touch of light on the label that someone saw on a vehicle that said it was OK for extended idle, in California right now there is a new law on the books that make it illegal to idle any medium or heavy duty engine for over 5 minutes continuos. I will tell you the law is very plain as only exempts a few uses one of which is any engine running a PTO. I was speaking to the roadside inspectors that had stopped two of my trucks and they showed me under the current air quality laws we could get around this idle requirement on any vehicle that met what they are calling 2007 specs (dpf) and if we had any of these new trucks which I have one with a new Cat in it we could apply for an exemption and we would be furnished with two tags (one for each side of the hood), that had to be posted for us to not be cited for extended idling. I have one of my field mechanics that was up at the local dealer the other day at the parts counter and one of the other mechanics warned him that a spotter was sitting out in the street and had issued several citations that morning for leaving service trucks idling at the loading dock