I'm new the diesel stuff, and the owners manual says to avoid "prolong idling". What the heck is prolonged??? So I'm at my dealers yesterday and he tells me, that after talking to an engineer(at cummins or CD< i'm not sure) that they don't advice idling the cummins any longer than 5 minutes, anything longer is hard on the engine.

Don't know if this is for all cummins or the gen 3??

I was surprised that it was so short, even in cold temps.

 

These engines do not want to build much for heat until they are under load. I start the truck, verify the oil pressure has come up then start to move. I drive easy until the temp guage starts to move. These engines tend to cool when idling, not build heat. Prolonged idling lets fuel wash down the cylinder walls.

 

3 minutes for the first start of the day...I thought I read that somewhere.

 

That is the best thing about diesel motors. They can idle all day and not burn much fuel at all. With my job it is usually hurry up and get there and then I end up having to wait. So my truck idles all the time. That IMO is a great option about these motors. As far as warm up time, depending on how cold it is outside I'll go from 5 mins to 15 mins.

 

Plugged in for 3 hours and a winter front with all the flaps closed = less than 5 minutes if you hit the highway.

 

You say you let your engine idle all the time, but from sources I have talked to and read aoubt, this should not be an option.

Idling is bad and harmful to the engine, you may want to reconsider your current practices. IMO. Just what I've been told.

 

Not trying to start a war here, but when mine idles it does burn more fuel. When they are below opp. temps. They acually inject twice as much fuel than when warm. therefor using more fuel. I like to plug mine in over night. Then in the morning get in and go as soon as the oil pressure is safe. The quicker you can get it to opp. temp. The less fuel you will use.

 

We (where I work) have always done that. I work in the oilfield and we may be out on the location for a couple of hours. For example in the winter time while we are on a job we leave them running. Also in the summer time we do the same. But while we are at our shop we do not leave them idling.

 

Is it bad if you turn the high idle on while its sitting?

 

Of course CUMmins will say idling is not good...Its not... But how much can idling hurt one of the most durable engines made. Mine will continue to idle as long as I need it to.

 

agreed 100%

 

I have a Kenworth T300 roll-off dumpster truck. It has a 8.3 ISC cummins in it. The Cummins owner's manual recommends 3-5 mins of "warm up" on high idle (1,000 rpm) prior to driving the truck. More time is required during cold weather.

I kind of apply that thinking to my smaller ISB engine that holds considerably less oil, coolant, and has smaller parts. During the summer/spring and early fall I let the engine warm up for 1 min or so for the first start up of the day. Normally start it up, find a good radio station, get all my junk put where it goes, get my drink situated, and then take off. I drive it easier than normal for the next few minutes. If I am going to tow, then I let it warm up for 5 minutes or so, and then tow with a light throttle for a little bit.

Extended idling is more than 5 minutes at low idle speed. I am confident that idling on high idle for a long time won't hurt anything. I don't even know if idling at low idle would hurt anything. I think some of the reasoning behind it is because of the cat and emissions. I think the government would like to see less idling. When you go into any truck stop a lot of those trucks are idling all night. We have an old F350 with a 6.9 liter. It has idled more than it has been driven. We bought it from a rodeo guy that left it running most of the weekend with the AC going while he or his wife slept in it. Then we did the same with it every time we went to the dunes. Always had a girl that didn't want to be in the heat. It has 282K on it with no problems.

If I know that I am only going to be a few minutes, I let it idle. If it is going to be 5 minutes or more, I shut mine off. This is my 4th diesel. I haven't ever had a problem with any of them.

BTW my truck DOES burn more fuel when idling than when it is shut off.

 

I have read several threads related to this topic about cylinder washdown and you shouldn't idle, blah blah blah.

BUT, nobody has EVER showed any documented proof that it harms a Cummins engine to idle. I say if you want to let it idle........go for it. All day, All night.......it's your fuel and engine.

Personally, I don't idle that long just because I don't need to. But I wouldn't be afraid to if the need were to arise.

I challenge somebody to show me where a Cummins engine failed from extended idling. I say it's hogwash, not cylinder wash.

 

My understanding is that it's the Turbo bearings that cannot handle the idling time. I was told that the oil flow is not enough to keep fresh oil going in to the bearings at low idle. Also that the Turbo will fry/burn the oil and we all know that burnt oil is not good lubricating the bearings.

 

That's exactly my position on the idling issue.