Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 11-29-2008, 05:25 AM   #1
Junior Member
Join Date: Oct 2008
Posts: 25
I've just got my first DP - 98 Endeavor - and trying to understand the diesel engine. I have the Cummins 5.9ISB. The manual states "Do not idle engine for long periods. Long periods of more than 10 minutes can damage the engine...." My question is: what about when you're stuck in traffic ? And how come many trucks keep their engines running for hours ?

1998 HR Endeavor - Freightliner Chassis
2005 Malibu Maxxi
Chonburiman is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 11-29-2008, 05:25 AM   #2
Junior Member
Join Date: Oct 2008
Posts: 25
I've just got my first DP - 98 Endeavor - and trying to understand the diesel engine. I have the Cummins 5.9ISB. The manual states "Do not idle engine for long periods. Long periods of more than 10 minutes can damage the engine...." My question is: what about when you're stuck in traffic ? And how come many trucks keep their engines running for hours ?

1998 HR Endeavor - Freightliner Chassis
2005 Malibu Maxxi
Chonburiman is offline   Reply With Quote
Old 11-29-2008, 05:31 AM   #3
Senior Member
Join Date: Jul 2005
Location: Pahrump, NV
Posts: 329
it's referring to idlinign without a load, if your trans is engaged then it is under load; if you need to put it into neutral ther eshoudl be a high-idle setting which is 'safe'; ours goes into high idle if cruise control is on and we press set on the cruise
2011 Airstream Classic Limited
2011 GMC Sierra 2500HD Duramax/Allison
Techie is offline   Reply With Quote
Old 11-29-2008, 05:35 AM   #4
Senior Member
georgetown350's Avatar
Monaco Owners Club
Join Date: Oct 2006
Posts: 1,603
Its a good practise to idle your engine for 5 to 10 minutes when getting off the freeway to let everyething cool down.

Your right trucks idle when sleeping 8 hours at a time.

To be safe I would call the manufacturer ( not the dealer) and ask them to explain their suggestion of not idling more then 10 minutes.
2008 HR 340 Cummins, Vacationer XL
georgetown350 is offline   Reply With Quote
Old 11-29-2008, 06:34 AM   #5
Senior Member
LVJ58's Avatar
Join Date: Jul 2000
Location: Las Vegas, NV
Posts: 1,999
Although I'm not a DP owner, out of interest I attended seminars hosted by CAT & Cummins at a couple of FMCA conventions.

What I gleaned from these seminars is that you don't need to idle a diesel engine for extended periods of time.

Those conducting the seminars stated that when you exit after freeway driving, by the time you get to an RV park or other destination the exhaust turbine will have spooled down and cooled down.

They also stated, on start up when leaving a campground or RV park, by the time you do a walk-around checking your coach coach the air pressure should be up to where you can drive off.

Both CAT & Cummins reps commented that all you do by long idles is waste fuel.

When the reps were asked what about truckers who leave their engines idle continually the response was "some do it to keep the cab warm or cool depending on the weather and that the company they drive for is usually paying for the fuel.

I would highly recommend all DP owners, if they ever get the opportunity be sure to to attend these seminars. I'm sure many already have.

The Allison folks also host very interesting and informative seminars at these conventions.

Happy Holidays to all, Jim
Jim & SherrySeward

2000 Residency 3790 v10 w/tags 5 Star tune & Banks system Suzuki XL7 toad
LVJ58 is offline   Reply With Quote
Old 11-29-2008, 07:58 AM   #6
Senior Member
JoeT's Avatar
Ford Super Duty Owner
Join Date: Feb 2005
Posts: 485
I wouldn't be concerned about being stuck in normal traffic, but if your stuck behind a wreck or something that your going to be stopped for an extended period I would either shut down the engine or set it to high idle. 900-1000 rpm.
An idling diesel engine does runs too cool and doesn't completely burn the fuel in the cylinders. This can wash the oil from the cylinders and shorten engine life
Then there's pollution to consider, too.
Joe & Loretta Fischer
2015 Thor Citation 29TB
JoeT is offline   Reply With Quote
Old 11-29-2008, 08:12 AM   #7
Moderator Emeritus
Gary RVRoamer's Avatar

Fleetwood Owners Club
Freightliner Owners Club
Join Date: Jan 2000
Location: Silver Springs, FL. USA
Posts: 16,446
LJA58's advice is right on the money.

Idling in traffic is the same as idling anywhere else. If it is going to be more than 5-10 minutes before you move again, shut it off. If it is stop & go traffic or a traffic light, don't worry about it. It won't be long enough between moving (loading the engine) to be of concern.

Just because truckers do something does not make it a recommended practice. You don't see them idling for long periods much any more either - that was the old days with older engine technologies that fouled easily and started poorly. Now they do it if they need the cab heater, but not much otherwise. And they will run the daylights out of their engine when they stop idling and get moving, whereas RVers typically do not.
Gary Brinck
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL
Gary RVRoamer is offline   Reply With Quote
Old 11-29-2008, 09:46 AM   #8
Senior Member
Rick & Hope's Avatar
Vintage RV Owners Club
Join Date: May 2008
Location: North Central Arkansas
Posts: 198
As a trucker with over 3 million miles I have to agree that there is no reason to idle a MH for extended periods of time. Truckers do it to heat or cool the sleeper while on their 10 hr break. In very cold weather(zero or below) they will also idle to keep fuel from gelling up.
1984 Heritage 2000 32 ft 1976 Jeep CJ7 toad
Rick & Hope is offline   Reply With Quote
Old 11-29-2008, 06:35 PM   #9
Senior Member
Steve Rankin's Avatar
Join Date: May 2006
Location: Olympic Peninsula, Washington
Posts: 108
Send a message via ICQ to Steve Rankin
We never idle our diesels for over 5 minutes, unless we simply can't avoid it. That includes in traffic.

When departing a campground, we get everything else ready to go except for those things that require the engine to be running, namely building up air pressure. Then we start the engine, retract the HWH jacks. It takes 2 minutes for the HWH system to cycle itself off automatically. By that time the air pressure is up and we're ready to roll. It's much better & faster to warm up the engine under light load than by idling it.

When we arrive at a campground we have invariably driven at least 3-5 minutes at low speeds so we shut down the engine immediately when we pull up in front of the office to check in.

Not only is idling the engine bad for the engine, it wastes a lot of fuel and contributes to pollution.

So why do some truckers still do it? Force of habit it probably the #1 reason. Being a trained diesel mechanic, I've heard all the stories. The two biggies are that (2) it's better for the diesel to let it idle than it is start & stop it, (3) the diesel engine uses almost no fuel at all when idling, and last but not least (4) it's part of the big man image.

(1) Consider this: If the typical truck driver has a 40 year career spanning from the time they're 20 till they're 60, the average truck driver today is 40. That 40-year old truck driver started 20 years ago, and learned most of what he knows--or thinks he knows--from older truck drivers. Guys that were 40-60 years old 20 years ago. Well-meaning, but definitely crusty old guys that would needle a young buck for just thinking about doing things some new fangled way.

(2) If idling was better then the engine manufacturers would say so. But, we have a culture in this country for shade-tree mechanics to think they know better than engineers.

(3) I worked with a bunch of those crusty old guys growing up as a mechanic. They all believed quite strongly that a diesel was so efficient that it hardly needed any fuel at all to idle. Well, the accepted rule of thumb is 1 gallon/hour. The big trucking companies have realized this for a long time, and have had policies to discourage unnecessary idling. As more and more truckers are realizing that idling their engine for an hour while they had lunch just cost them $4-5 for a gallon of fuel, and idling all night long cost them $30-40 they're shutting their rigs down. It adds up even for the RV owner. Thirty minutes in the morning while getting ready to break camp, 15 minutes at each rest stop, an hour during lunch, and 30 minutes when arriving at the CG & setting up. That's 2.5 hours of idling; 2.5 gallons of fuel or better than $10/day.

(4) All you have to do is talk to a few guys with their big DP's about how long they idle their engines and see how defensive they get to understand that a major reason they idle their engines is to look cool. The sound of that big expensive diesel idling is music to his ego.
Steve & C. J.
2009 Arctic Fox 29V PullRite 20K hitch
2005 Chevy Silverado 2500HD 4X4 Duramax/Allison
Steve Rankin is offline   Reply With Quote
Old 11-30-2008, 06:22 AM   #10
Senior Member
Join Date: Apr 2003
Location: Oakton, Va
Posts: 1,135
Steve summed up the idling question much better than I could have. He is right on. Doc said he would just let Steve's post go without objecting and then did just that. There is something about a diesel engine idling that makes one want to let it keep purring along, but that has no credible logic after the short cool down period if over. Cummins says 3-5 minutes for the cool down and as Steve writes, you don't need that if you have been driving slowly between the highway and the campground for about five minutes. At a seminar a Cummins rep stated that the life of their engines was based on revolutions. More revolutions idling are revolutions subtracted from their life. Idling compounds the problem by running at less than normal temperatures which can cause fuel washdown of the cylinders. I cringe when I see the large tractors idling for hours.
Jim Walker
N Virginia
2014 Palazzo 33.2
Cummins 6.7 ISB, Allison 2100 6 Speed
J Walker is offline   Reply With Quote
Old 12-01-2008, 05:52 PM   #11
Senior Member
SargeW's Avatar
Join Date: Sep 2002
Location: Fallbrook, Ca
Posts: 1,121
Yep, diesel wash. VERY BAD
Marty and Diane, Fulltiming!

Our Travel Blog www.mytripjournal.com/rvnchickalaska
SargeW is offline   Reply With Quote
Old 12-04-2008, 04:12 AM   #12
Senior Member
Ray,IN's Avatar
Join Date: Aug 2001
Location: North America somewhere
Posts: 12,303
Diesel idling wastes fuel and adds tons(literally)of pollutants to the atmosphere. This is now recognized by many state governments, who have passed idling laws. Many truck stops now have rows of spaces dedicated to truck cab heaters with an electric outlet included; the cost to the trucker for this is much less than the cost of idling that huge diesel engine for 8-10 hours.
Steve Rankin, thanks for your elequent explanation. May I copy N paste it to other discussions, with a proper attribute statement of course?
2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member."We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert theConstitution. "Abraham Lincoln"
Ray,IN is offline   Reply With Quote
Old 12-04-2008, 05:44 AM   #13
Moderator Emeritus
RustyJC's Avatar

Texas Boomers Club
Join Date: Jul 2000
Location: Cypress, Texas USA
Posts: 8,851
Actually, when the 24 valve 5.9 Cummins was introduced, there was a problem with bent pushrods (push tubes, in Cummins' parlence) that was traced to engines that had been subject to excessive idling. The problem was that the new 24 valve cylinder head was so efficient in cooling the valve stems that the valve stems and guides ran cold enough during extended idling that varnish would form on the stems and guides causing valve sticking and resultant bent pushrods/push tubes. If the engine was equipped with an exhaust brake, engaging the exhaust brake during idle placed enough load on the engine and raised exhaust temperatures enough to alleviate the problem.

There was a Cummins TSB issued on this topic. HERE is the Dodge TSB that reprogrammed the ECU to deal with the problem. HERE is a Cummins service note discussing the subject.

2016 Ram Longhorn 3500 Dually 4x4 CCLB, 385/900 Cummins, Aisin AS69RC, 4.10
2014.5 DRV Mobile Suites 38RSSA #6972
Come join us on a TEXAS BOOMERS rally!
RustyJC is offline   Reply With Quote
Old 12-04-2008, 06:57 AM   #14
Senior Member
Workhorse Chassis Owner
Join Date: Jun 2006
Location: Northwestern Montana
Posts: 3,009
[QUOTE]Originally posted by Ray,IN:

Many truck stops now have rows of spaces dedicated to truck cab heaters with an electric outlet included;

Now if there was only some way to get the states to install these in the roadside rest areas along the interstates, we could all sleep better. Don't you just love the sound of an 18 wheeler idleing while parked next to you in a roadside rest.


dieselclacker is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Workhorse Front Engine Diesel Full-Timers Workhorse and Chevrolet Chassis Motorhome Forum 24 08-18-2008 06:20 PM
Diesel engine in the future? diandtom Just Conversation 13 07-16-2008 04:19 PM
Diesel Idling Gadget Man Class A Motorhome Discussions 17 11-16-2007 04:45 AM
New 2007 Diesel Engine rdjl9722 MH-General Discussions & Problems 4 05-01-2007 05:00 AM
Metallic sound in muffler when idling surfride Workhorse and Chevrolet Chassis Motorhome Forum 5 06-13-2006 10:29 AM

» Virginia Campgrounds

Reviews provided by

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 02:49 PM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.