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Freightliner diesel idle speed Q?

K85 Octane

K85 Octane

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Question for the big diesel engine guys.

My fathers new RV says Freightliner Chassis on the side; it's a bus chassis. Anyway, the dealer said if we let it run for any length of time, that we should kick up the idle to 1200rpm. Letting it idle at the lower speed for more than XX minutes will be logged into the computer and void warranties if problems occur.

What the heck is all this?
My fathers CCLB Dmax also has this "elevated idle" setting (on/off). What's that too?

Thanks:waytogo:
 
on our work trucks, you can kick it to high idle by setting cruise ON in park and hitting the ACCEL setting a couple times... weird, my truck idles all day and at 59k it burns a gallon and a half of oil a week.. maybe there's a reason
 
What model year, what engine?

Low idle for extended periods of time on any diesel will give you problems. Wet stacking the cylinder being the most common. When idling the cylinder temperature drops. And you start getting incomplete burn of the fuel. Glazed the cylinder walls, rings stick. Loss of compression. Fuel in the oil. That can wipe the bearings. It just reeks havoc on emissions equipment. Seize the egr valve, the vnt or vgt actuator on the turbo (depending on the engine)

It's just not a good thing to do.


Sent from my Desire HD using Tapatalk
 
wow, interesting stuff

The longest we ever have it idling is waiting for a family member to get back from McDonalds and eat. So maybe 30 minutes, be we always bump up the idle with the CC. I'm just surprised the idle needs to be brought up, but now I understand. Does that mean all those bigrigs I see on the side of the road with their engines running are running at a higher idle all night long? (not cold enough around here for freezing problems)
 
They should be. Most are not. Lots of truck drivers don't know or don't care.

The colder the intake air temp the worse the problem will be. absolutely decreases the service life of the engine.

Many otr longhaul rigs now days have tripak units for heating cooling and power, so the engine does not have to be run when not driving. Well actually clean air idle certification for California prohibits any idling over a few minutes. And its programmed into the ecm. The engine will shut off on its own.

Idle timer fires the cel and sel, and kills the engine, but I know Detroit does not monitor those occurrences.





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Our garbage trucks all shut down after about 5 minutes idling. Seeing how they get worked, my bigger concern is having it shut down with a hot turbo...

Rene
 
We don't idle it up, because it's normally never idling longer than it takes for a light to turn green...

Keeping them cool is harder than keeping them 'hot'.

Rene
 
Ya no, I taking about what you said about shutting down a hot turbo. Cause you're right hot turbo shutdowns don't take long to coke up that shaft. The its gameovr for that baby.

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Yeah, one of the first things I was told...let it idle for a few minutes before shutting it down to keep from coking up the turbo. Funny thing is I regularly see one of the 'old timers' on Tuesdays. We usually pull into the yard right around the same time. Often enough I'm finishing my post trip when he pulls into the spot next to ours. He regularly pulls in, and shuts it down immediately. i cringe every time he does it...

I figure they see enough abuse during the day just getting the work done, why add to it?
 
That's just it people fall into 2 categorys 1- don't know 2- don't care.

More often its #2.

I also depends on what oil is being used and just how hot the turbo is.

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Yeah, I guess it's likely not smokin hot as he would have come directly from the transfer station to the yard. Usually idle in line for the scale for 2-5 minutes, work the truck a little to push the load off and then an easy 5 minute drive to the yard. It's likely the oil is already cool enough that shutting it down without a minute or two of idle isn't going to hurt it...

I figure better to be somewhat sure, so when I arrive at the yard I let it idle while I get out, kick tires, check lights etc. By the time I'm done doing that I'm certain oil temps are where they need to be, and I'll shut it down.
 
DEMON44 said:
That's just it people fall into 2 categorys 1- don't know 2- don't care.

More often its #2.

I also depends on what oil is being used and just how hot the turbo is.

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Click to expand...

I have a question for you.
I usually have a cooldown slowdown 5-10 minutes before I get to my final stop, and when that happens I usually give it 2-5 minutes and I shut it down.
If I was pulling a hill and I had to stop, I usually let it idle at least 10 minutes before I shut it down.
I do not idle overnight, the longest is if I am in traffic and if it's completely stopped for 10 minutes I shut it down.
I know it's bad to idle with no load but it also hurts my wallet.:D
But is an easy drive , almost rolling for the last 10-15 minutes good enough to cool it down plus the 2-5 minutes idling before I shut down?
 
One thing I have always wanted on my vehicles is a preoiler. Years ago, SAE came out with a study that said that almost 80% of wear in an engine occurs between the time an engine starts and when oil pressure gets up to spec.
Perhaps more importantly, when oil flow gets to the parts.

I think that synthetic oils have reduced this some, because they keep a better oil film when shut off and flow faster.

They have a couple of different types of preoilers. The simplest and cheapest are just pressure tanks with check valves and a solenoid valve.
The oil pump fills the tank up to the maximum oil pressure. When you turn the key to on, the solenoid valve opens and the tank pushes the oil into the system ahead of the cranking.

But, the one I liked was a pump that came on and pressured the system before you started cranking.
You would turn on the key and wait for the light to go out or the gauge to read normal oil pressure.
It would maintain the pressure as long as the key was on and the battery good. So, you did not have to crank it right away as with the tank.

But, another benefit, was a timer that kept the oil circulating for a set time after the engine was turned off.

If I had a turbocharged engine, I would definitely try to get one of those along with an oil cooler.
It pretty much would have to increase the life of the bearings in the turbo to keep the oil circulating and cooling until the turbo cooled off.
 
We have to program around the idle shut down now at work. Federal emmisions are going the way of California, and all of the manufacturers we deal with on a regular basis have tried to stay ahead of the fed's here and follow California. International, Freightliner (Cummins), and the few Cat's we see are all set up for the 5 minute idle shut down.

We have to disable that when in PTO, and idle up (either set speed or variable). We get calls pretty regularly from customers whom have taken their trucks to the dealer for recalls/service. The dealers will sometimes reset some of the ECM set points, affecting PTO parameters, thus killing their trucks 5 minutes after parking at a job site. (Aerial bucket trucks, digger derricks, pressure diggers, cranes, etc.)

I have not experienced anything other than an International do this, but they will display the Regen symbol on the dash and if parked regen is allowed, will idle up to clear the exhaust filter. They get pretty damn hot doing that, not something you want to do in a field or over brush.

From what I hear from customers with trucks that consume the new DEF, they drink it up pretty quick. Seems like it is going to hit some fleets with a heafty added "fuel" cost over the course of a year.
 
DEMON44 said:
That's just it people fall into 2 categorys 1- don't know 2- don't care.

More often its #2.

I also depends on what oil is being used and just how hot the turbo is.

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Click to expand...

Count me as #1. Thanks for the info though. I think we need to be idling up when we park, to prevent the wet stacking you speak of. After googling it some, I notice some common conditions, like the black ooze around exhaust connections, being tell-tale signs off this issue. Thanks!
 
tRustyK5 said:
Our garbage trucks all shut down after about 5 minutes idling. Seeing how they get worked, my bigger concern is having it shut down with a hot turbo...

Rene
Click to expand...

Our 98 Freightliner Semi (detroit motor) shuts down after 15 minutes of idle as well.... is this a dummy check so that someone doesnt leave their truck running or to prevent all of the previous problems that occur with trucks running at low idle?

(not necessarily directed at tRusty)
 
My understanding is it's there for all the reasons listed above, except for the dummy check.
 
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