diesel_burner

Man, I thought that I was going to be the hero of this thread. Oh well. I guess next winter I'm going to start it in Sept. To May. I will let you guys know how the carbon build up is.

triplenickle

As in "idle", do we mean 750 rpm, or a bumped up idle, like 1250 or 1300 rpm?? Im guessing that as long as it isnt at "idle", the motor wont really care. If the idle can be set between 1300 and 1500 rpm, that motor won't know if it is a generator or other stationary motor, thus no carbon build up or wash down. Look how many tractors are used for weeks and months at a time with the PTO hooked up to the dryers or a fire truck that sits at a big fire and flows water for a few days or week. But man, that'll kill your ave. MPH!!

Patrick Campbell

Difference is even if you rev it up to 1200 rpm there is no much load on the engine at all. A/C is not that much load but I always use it when idling and rev up.

LonestarCTD

I'm actually pretty amazed at the responses here. The Cummins website made mention of idling at one point in the past, and if I remember right it said that it was ok to idle up to 5 mins with no problems but that idling 10 mins or more at low idle (750 rpm) would result in cylinder washout, dilution of engine oil, and valve damage if done for extended periods. I looked into this when I first bought my truck and have never really let it go over 10 mins max because of this information. It was posted on the FAQ page of the Cummins website but has since been changed. But, I am certain of the numbers that were posted because I still abide by them even now.

** UPDATE ** - Just found the info I had read:

From the Cummins Webpage:

Do not idle the engine for excessively long periods. Long periods of idling (more than 10 minutes) can damage an engine because combustion chamber temperatures drop so low the fuel will not burn completely. This will cause carbon to clog the injector spray holes and piston rings, and can cause the valves to stick. If the engine coolant temperature becomes too low (60 degrees C [140 degrees F]), raw fuel will wash the lubricating oil off the cylinder walls and dilute the crankcase oil; therefore, all moving parts of the engine will not receive the correct amount of lubrication. (For more information, refer to Cummins Operation and Maintenance Manual section 1-5, Bulletin 3810205-12.)

Hope this helps

TexasCTD

Has anybody ever seen any documented proof of cylinder washdown damage?

It makes sense I guess.....about the description of cylinder washdown, but I see lots of rigs idle and the engine keeps on running without complaint.

I'd love to see some sort of test as to HOW much damage is done to the engine to start it up cold..............vs............letting it run all the time.

I'd be curious to know if it is possible to start up a Cummins and never shut it off except for once every couple of months to change the oil and filter. Would it really REALLY damage it??

We hear about it all the time (cylinder washdown), but I have never heard of a Cummins engine suffering any damage from this. Big Rig trucks run for weeks at a time too.

DTroy

One of our local Dodge owners has a job that requires him to work out of town on a regular basis. He may be gone for weeks at a time.
He was working long hours and couldn't justify spending money on a hotel room when all he was going to do was lie down and sleep.
- You can take a shower at a truck stop for 2 or 3 dollars -

He ended up putting a heater core in the bed of his truck. (he has a shell) And then he plumbed in an A/C core in the back. So now he can sleep in the back on his cot with either heat or air conditioning.

He lets his truck run all night, every night. He's been doing this for years.

wcbcruzer

Big rig engines were designed to have the engine running (including idling) all the time. I don't know exactly what the differences are which allows them to do this... I guess if the nature of your job calls for you to leave your truck idling, then there is no problem. I mean, yes maybe your engine might go bad a few years sooner, but at least during the 10 years you owned the truck you were comfortable and able to work. You just just might have to do an overhaul a couple years sooner, oh well...

Patrick Campbell

If you are going to idle I think the general consesus is to get the rpms up to around 1200. I would not idle for long periods of time without it. Sleeping in the bed with a topper sounds fun Sleeping on the bench gets old fast. I never had to pay for a shower, just use the frequent fueler card and the free shower and coffee are always waiting for me

DTroy

On my trip to Colorado I was sleeping on the back seat. The HRVP causes my truck to have a lumpy idle. And I had a small injector line leak at the time which made it even worse.

So the Cummins was shaking the truck. It rocked me to sleep each night.

Mountaineer

At least 5 min.

Ddge6spdRam

During the winter the truck in usually running from the 30 minutes before we leave till the time we pull into back into the driveway. Probabley the longest the truck has idled has been close too 12 hours or so..

Jeff

Tank_66

well I work on teh service rigs and one day I came to work adn my pump truck was deader than crap on sunday so i boosted it adn all my power was gone no lights nothin... so I let it run all day cuz Iwas scared if I shut it off I would not get her tostart up again... so at the end of the day I was ready to go home so I said well ***** I'm gunna shut her off adn see what happens, I shut er down and fired her back up adn she had all power adn everythign was fine... kind of a waste of fuel but oh well... so about 16 hours or so was my most

blord

The issue is wet stacking which causes deposit to form where there shouldn't be deposits. The only place 06 manual mentions extended idle being a problem is under "cold weather operation". It says to use "fast idle" and/or a Jake brake to keep the engine temp close to normal operating temp.

I sent an email to Cummins and asked about extended idle. I also asked about wet stacking since I had read in another forum that it isn't a problem with modern fuels and computer control.

This is from Cummins:

TexasCTD

Blord,

Thanks for the info. I don't do alot of extended idling so im not to concerned about my truck.

But, again......I have yet to hear about anybody on this forum or elsewhere that actually had engine damage from wet stacking. I'd be curious to know if anybody has and can say definately that that was what caused the engine failure or premature wear.

wcbcruzer

I remember reading one thread where a guy had to do an engine overhaul at 150K miles. He said it was a fire department truck... So it's very possible that truck was left idling for long periods of time...