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Extended idling??
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=10971		 Page 1 of 1
Author:  Tinman [ Mon Jul 31, 2006 2:15 pm ]
Post subject:  Extended idling??
Anyone know if it is OK to let the CRD idle for extended periods of time? By extended periods I mean up to an hour. I know on the Dodge/Cummins that's a no-no, expecially in the common rail motors. Reason I ask it that we travel with the dogs a lot in summer in the south and it is just too hot to let them stay in the vehicle without the air. Mostly it's when we stop to eat or run in a retailer. My Cummins' have high idlers on them which will idle'm up to 12-1500. Works great and keep the combustion chamber temps high enough to prevent problems. Just wondering about the CRD.
Author:  railguy [ Mon Jul 31, 2006 3:18 pm ]
Post subject: 
I talked to the DC technical people about this over a year ago. First, I don't recommend extended idling for obvious reasons--it places what may be unnecessary wear on the engine and it wastes fuel. That said, there are circumstances that extended idling may be warranted. What the DC tech told me is that exended idling should not bother the CRD. The big problem with extended idling is "wet stacking"--the buildup of unburned fuel due to the engine's operating temperature dropping below the needed level to completely burn the fuel. Other diesel engines can get around this problem by "idling up" (manually or automatically) to a higher rpm to raise combustion temperatures. Of course, high idle burns more fuel. The DC tech said that the viscous heater eliminates the need for high idle, because it will cycle on to maintain engine temperature within the needed range to completely burn the fuel. I haven't had to extended idle my CRD to test this theory, but it would seem to make sense.
Author:  jeep06 [ Mon Jul 31, 2006 3:28 pm ]
Post subject:  idle temp
Dodge/cummins said on the earlier (pre-Common rail) engines not to idle engine for longer than 10 minutes if the coolant temp was below 140*. That was the min. temp for proper combustion temp. Not sure if the same rule would apply to this engine or not.
Author:  Tinman [ Mon Jul 31, 2006 4:12 pm ]
Post subject: 
On the pre-common rail Cummins, I have heard of carbon build up from too- low combustion temp to the point of catatrophic engine damage. On the common rail Cummins the injectors are also suspect to carbon damage and I have heard of warrenties voided because evidence of extended idling. That's why I was asking. Of course, when it's 95 degree out, the engine is at operating temp and the A/C compressor is on, I doubt any engine will cool down to a point of wet stacking. Idling all night in the dead of winter with the heat on...that's another story.
Author:  RFCRD [ Tue Aug 01, 2006 12:15 am ]
Post subject:  Re: idle temp
jeep06 wrote:
Dodge/cummins said on the earlier (pre-Common rail) engines not to idle engine for longer than 10 minutes if the coolant temp was below 140*. That was the min. temp for proper combustion temp. Not sure if the same rule would apply to this engine or not.

This is basically what I was cautioned about with other Detroit Diesel products used in buses. The 4-strokes will burn cold causing it to loadup on fuel/soot. This eventually works it's way past the rings and contaminates the oil. On their older 2-strokes, they will loadup on oil badly. On either type on engine, running on fast idle is a must to minimize these problems. DDC rep plugged a Prolink into my last Series 60, showed me the % idle time and threatened warranty cancellation if not stopped. Suggest not doing this with the CRD engine.
Author:  onthehunt [ Tue Aug 01, 2006 7:53 pm ]
Post subject: 
The worst thing you can do to an egr equipped diesel is idle it. Stay away from extended idle time!!
Author:  Drewd [ Tue Aug 01, 2006 8:51 pm ]
Post subject: 
I suspect the turbo seals need boost pressure to keep them sealed and working properly.

EGR I believe is very active at idle and low power settings (If I am wrong please correct me)

Diesel's can wetstack if they do not have an adequate load put on them. Not good.

I personally wouldn't do it but if it is to keep a loved one (dog) comfortable than it'd be worth the risk.
Author:  Jeger [ Wed Aug 02, 2006 9:23 am ]
Post subject: 
So how is it that semi's idle for hours on end..all night even, and still go 1million miles? Are they set up for this somehow?
Author:  oldnavy [ Wed Aug 02, 2006 9:49 am ]
Post subject: 
Jeger wrote:
So how is it that semi's idle for hours on end..all night even, and still go 1million miles? Are they set up for this somehow?
Yes they have high idle throttle either hand or automatic.

Some of the new truck stops now have islands with heat or a/c that can be attached to windows so as not to need to waste fuel with engine running while driver sleeps/eats/showers or whatever, some trucks have aux small diesels that run a/c and even keeps engine coolant warm from what I have read. The savings in fuel cost seems to have paid for the aux diesel in just a few short months and the same for the use of the rental a/c and heat at truck stops.
Author:  alljeep [ Wed Aug 02, 2006 9:49 am ]
Post subject: 
Jeger wrote:
So how is it that semi's idle for hours on end..all night even, and still go 1million miles? Are they set up for this somehow?


I was waiting for someone to ask this, as I want to know too. Maybe older vs. newer semi trucks???
Author:  RFCRD [ Wed Aug 02, 2006 9:58 am ]
Post subject: 
Jeger wrote:
So how is it that semi's idle for hours on end..all night even, and still go 1million miles? Are they set up for this somehow?

Not really, other than the lack of an EGR they have the same arrangement. Many times it's the lesser of the evils. I do it with a road coach in extreme cold to keep the fuel warm and pneumatic system from icing. The eye-burning exhaust fumes indicate unburned fuel (so-called wet-stacking) from the engine running cold. You probably won't smell this on the CRD due to the catyletic converter, but will still be present. This is an obsolete practice at $3/gal, oil fired heaters, and automatic devices that start and stop the engine periodically to keep it warm.
Author:  Cowpie1 [ Sat Aug 05, 2006 4:14 am ]
Post subject: 
oldnavy wrote:
Jeger wrote:
So how is it that semi's idle for hours on end..all night even, and still go 1million miles? Are they set up for this somehow?
Yes they have high idle throttle either hand or automatic.

Some of the new truck stops now have islands with heat or a/c that can be attached to windows so as not to need to waste fuel with engine running while driver sleeps/eats/showers or whatever, some trucks have aux small diesels that run a/c and even keeps engine coolant warm from what I have read. The savings in fuel cost seems to have paid for the aux diesel in just a few short months and the same for the use of the rental a/c and heat at truck stops.


When I need to idle my semi, I engage the cruise control which steps up the motor to a PTO idle (approx 900 RPM). During the recent "hot" spell, that meant for up to 8 hrs. It is true that there is some carbon/soot buildup, but this is purged by 11 hrs of highway driving with 80,000 lbs. This really works the motor, especially in hill country.

The APU units that are on some trucks currently sell in the $7-8K range. They do save a considerable amount of fuel, but the break even point is not reached for over a year.

The "idle-air" setups at some truck stops are really only for a limited number of trucks. They are only located in high volume stops along the major east-west routes. They are useless for majority of trucks since most of us need to take our breaks at loading/unloading locations. Therefore, unless the truck owner decides to install the APU's, the driver is forced to idle the truck.

It does cause wear and excess fuel use, however, if done in moderation and good driving technics used, the amount of fuel and wear is not excessive. To point: I have averaged 7+ mpg over the last 11 years and put on 1.4 million miles on my last truck without an overhaul or major repair. Considering the industry mpg average is 6 or less, the amount of idling I have done has not been a serious enough issue to justify 8k for an APU. Just by getting a 1+mpg more than the industry average saves approximately $7k a year in fuel at the current price. But that is on a semi.

All being said, unless you have a real need to idle the engine, don't. It is never a good option unless absolutely necessary. I never idle unless I am in the semi and needing rest in hot/cold weather. I never idle the truck when I am out of it, even in -20 weather. That is what a block heater is for. For hot weather, crack a couple of windows and shut the vehicle off. I do the same with my CRD. The idling done with most diesel engines is unwarranted. It comes from old wives tales and such. Modern diesels do quite well starting in cold weather, even after sitting with block heater unplugged for up to 4 hrs in the most extreme cold weather. The only situation I ran into that caused me to not shut the truck off for any reason was running the interior of Alaska in the middle of winter. But that was to keep the diesel fuel warm just as much as keeping the engine warm.

Unless it is a matter of life or death, I would advise not idling your CRD for extended periods of time.
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