# Diesel Idling



## Ed Williams

I was surfing YouTube and found a post from Adept Ape on diesel engine idling. He is a certified diesel mechanic and has many YouTube videos that are very informative, mostly on big rig diesels. The video I ran across said to never run a diesel at idle for any length of time as it would damage the motor and require a premature Rebuild. And this applies to all diesel engines. He never explained why running a diesel engine at idle would cause damage. He recommended not to ever run a diesel motor below 1000 rpm. Can anyone shed some light on this? My tired brain cannot comprehend this at all. What is the difference between running at 750 rpm and 1000 rpm that would damage a motor? What about all the trucks I see at rest areas, truck stops, and interstate ramps sitting all night with the motors idling? If I am doing my normal chores, I usually just let the tractor idle for 10-15 minutes to complete each task, then proceed to the next item on the list. I thought this would be easier on the tractor than startING and stopping the motor 10 times each evening. Am I damaging the tractor doing it this way? Please share your opinions. I know my brother in law let's his tractor idle while feeding the cattle, which is about 30 minutes for each feed lot.


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## bmaverick

Both my Yanmar manuals and the equal John Deere manuals both say not to idle more than 10mins at any given time unless there is a load applied like a PTO conveyor or a wood chipper or saw. 

Getting the RPMs up ensures the oil can circulate to the upper engine parts much better than a near stall idle. Heck, it's diesel, it's not going to run out of fuel that quickly, so 800 to 1,000 RPMS is fine in my use. 

Now, I did find talk about Ag diesel equipment made before the 1990s. There are issues to consider ...

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On low idle, a lot of diesel motors will not produce enough heat to a) fully expand the metals to seal mating surfaces and b) to fully burn the fuel. 

This causes what is called “wet stacking", where the unburnt fuel exits through the exhaust. It may also wash off the film of oil on the cylinders and may cause liner damage. Fuel may also dilute the crankcase oil.

I avoid idling my diesels, and have a provision for high idle on all of them if I have to (battery protection for low power pto). 
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My Yanmar was made in 1981. Same machine engine family as a John Deere 850/950/1050 era tractor. These have liners in the block. Thus, the above quoted statement seems to be helpful for understanding. 

Should a diesel engine have a wet stacking event, you will notice when the RPMs get above 2200, the exhaust will spit out large clumps of semi combusted diesel and plumes of dark grey smoke. Just keep the engine running at that set point to achieve a normal operating temperature to help purge the engine and exhaust clean. Failure will lead to more engine failures otherwise. There is soooo much info on the web about wet stacking and diesel engines.


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## Bob Driver

It's not unusual to see over-the-road tractors with 25%-35% idle time, especially if it's a sleeper unit. Day-cab Pickup/delivery tractors and vocational trucks (dump trucks, logging trucks, oil field trucks) can run anywhere from 35% to 50% idle time. They start at 6AM and shut them off at 6PM. Most idle at around 800 RPM. Most units have some sort of "High Idle" setting that allows you to bump them up to 1,100 RPM. This is more to spin the alternator faster to charge better with the marker lights on while you're parked and generate a little water flow for heat when you're idling at a truck stop and it's 10 degrees.

Heavy idling has been around in the trucking industry forever. It cost trucking fleets millions of $$$ every year in "non-productive fuel", but is not really a problem for engine durability other than it causes 2010+ emission engines to need to Regen more often. I would guess ol' Adept Ape has never been around many shrimp boats before, they idle for days on end. If you've ever operated trucks, or heavy equipment in an arctic environment, you understand it's much easier to idle the equipment all night than it is to start it at -20.....


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## bmaverick

Bob Driver said:


> It's not unusual to see over-the-road tractors with 25%-35% idle time, especially if it's a sleeper unit. Day-cab Pickup/delivery tractors and vocational trucks (dump trucks, logging trucks, oil field trucks) can run anywhere from 35% to 50% idle time. They start at 6AM and shut them off at 6PM. Most idle at around 800 RPM. Most units have some sort of "High Idle" setting that allows you to bump them up to 1,100 RPM. This is more to spin the alternator faster to charge better with the marker lights on while you're parked and generate a little water flow for heat when you're idling at a truck stop and it's 10 degrees.
> 
> Heavy idling has been around in the trucking industry forever. It cost trucking fleets millions of $$$ every year in "non-productive fuel", but is not really a problem for engine durability other than it causes 2010+ emission engines to need to Regen more often. I would guess ol' Adept Ape has never been around many shrimp boats before, they idle for days on end. If you've ever operated trucks, or heavy equipment in an arctic environment, you understand it's much easier to idle the equipment all night than it is to start it at -20.....


The trucking industry has been converting over to no-idle heating and cooling systems now for the past 20 years. Diesel and the oils have less zinc and other anti-wear properties these days due to environmental regulations. 
https://us.bergstrominc.com/nite-phoenix


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## Ed Williams

So to be safe, I need to bump up the idle to 1,000 to 1,100 rpm to avoid engine problems and aide in recharging the battery. Fuel consumption is really not a factor, maybe a gallon or so a week at most. More concerned with preventing damage to motor. I looked at my operating manual and could not find anything on operating on idle. It only gave the idle speed. I will look over again to see if I missed anything. Thanks for the info.


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## bmaverick

Ed Williams said:


> So to be safe, I need to bump up the idle to 1,000 to 1,100 rpm to avoid engine problems and aide in recharging the battery. Fuel consumption is really not a factor, maybe a gallon or so a week at most. More concerned with preventing damage to motor. I looked at my operating manual and could not find anything on operating on idle. It only gave the idle speed. I will look over again to see if I missed anything. Thanks for the info.


Yes, that makes sense. Keeping the idle a tad up would help the engine temp and oil moving around a bit better. 

I try not to idle in the winter time too long as my diesel engine has cylinder liners. When snow plowing, it's bone cold out there with the wind. At the right position facing the wind, I can feel the heat of the engine flow over me on the seat.


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## Ed Williams

This is my first winter with a diesel. Have always used the NAA with chains. Total Wt with ballasted tires and chains about 3,800 pounds. The new to me 4000 with ballasted tires and no chains is about 8,300 pounds. The NAA does OK at removing snow, but struggles when pulling cars out of a ditch. Pretty much hit or miss depending on situation. Hoping the extra weight and locking differential of the 4000 will do better wheRe the NAA is struggling. I normally push snow at 1200-1300 rpm and 1 & R gears. Seems to be a lot more efficient to keep speed down, especially with blade reversed to push snow backwards. Hoping the 4000 will do better with the added weight and locking differential. I can always add an "H" link to the chains and transfer to the 4000 if needed.


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## Ed Williams

When pushing snow, it is usually so cold I can feel nothing. I put on my 7-10 layers, see Charlie Brown look alikes and go to it. Come home periodically to warm up aND thaw frozen parts. Serious cabin with heater envy flareups are cmmon this time of year.


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## Bob Driver

bmaverick - You do realize that auxiliary unit you linked to with *both* heat and A/C (only 7,500 BTU's of either) is $9,000 fully installed and you have to cut holes in a $150,000 sleeper truck to mount it?? It also comes with a whopping 2 year limited warranty.... I had one of their salesman driving me crazy with phone calls a couple a years ago, before I retired. He was going to save me a ton of money on "idle fuel" and all I had to do was spend $9,000,000 to put them on a 1,000 truck fleet.... He was getting a 3% commission on the deal. 

"The trucking industry has been converting over to no-idle heating and cooling systems now for the past 20 years"... Name names... I personally know dozens of guys that run big OTR truck fleets and the ROI math doesn't work out for anybody, even on factory installed APU's ($14,000 on my last price sheet from PACCAR), until diesel fuel hits around $4 per gallon on a truck you're depreciating over a 6 year life-cycle.


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## bmaverick

Bob Driver said:


> bmaverick - You do realize that auxiliary unit you linked to with *both* heat and A/C (only 7,500 BTU's of either) is $9,000 fully installed and you have to cut holes in a $150,000 sleeper truck to mount it?? It also comes with a whopping 2 year limited warranty.... I had one of their salesman driving me crazy with phone calls a couple a years ago, before I retired. He was going to save me a ton of money on "idle fuel" and all I had to do was spend $9,000,000 to put them on a 1,000 truck fleet.... He was getting a 3% commission on the deal.
> 
> "The trucking industry has been converting over to no-idle heating and cooling systems now for the past 20 years"... Name names... I personally know dozens of guys that run big OTR truck fleets and the ROI math doesn't work out for anybody, even on factory installed APU's ($14,000 on my last price sheet from PACCAR), until diesel fuel hits around $4 per gallon on a truck you're depreciating over a 6 year life-cycle.


PACCAR divisions Peterbuilt and Kenworth. Navistar has a few in selected trucks too. These are supplied OE and not as after market. 

That's a wild price for aftermarket.


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## bmaverick

Ed Williams said:


> When pushing snow, it is usually so cold I can feel nothing. I put on my 7-10 layers, see Charlie Brown look alikes and go to it. Come home periodically to warm up aND thaw frozen parts. Serious cabin with heater envy flareups are common this time of year.


Ed, should I become stuck up in the great white north with the same weather you have, I'll be seriously looking at a RK37SC with heated cab. 

What you had describe is what I'm doing now with the YM2610 and a straight blade pushing in reverse. WI snow and blowing winds are nasty here in the mid-west. 

BTW, did you change your oil for winter season use before the temps dropped. I'm not sure what a Ford 4000 would use.


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## Hoodoo Valley

bmaverick said:


> At the right position facing the wind, I can feel the heat of the engine flow over me on the seat.


Not here. The wind at zero to -30 flat out kills any heat coming off my tractors. 

That emoticon signifies chattering teeth by the way.....


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## Ed Williams

I did change to 5w-30 Rotella and new Motor craft filter per the operating manual specs. I also changed the fuel filter at the same time. Old oil looked very clean, so now I am saving the old oil in a 55 gal drum and looking at plans to make an oil assisted wood stove from old truck rims. A mechanic in town is using a stove in his shop with same construction that is 100% oil fired. He said the stove is saving him over $3000 per year in electric bills and disposal costs.


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## Ultradog

I'm thinking when people don't have enough to worry about they'll invent something.
Maybe on a modern, high tech Tier IIII diesel there is a reason to not idle them too long.
On a 40-50 year old farm tractor idle periods would be the last of my concerns. Yes, you'll get a bit of wet stacking if you idled it for hours and hours. You'll get wet stacking if you just putter around while working it too. Diesels do like to run harder and hotter than a gasser does. Diesel fuel is not as volatile as gasoline is. So to get maximum efficiency out of a diesel you run them hotter and harder. The old 1957-64 four cylinder Ford diesels even used a 2 blade fan instead of the 3 blade fan used on the gas models of that era just to get the engine temp up.
I could look up the idle specs on a 3 cyl Ford diesel but will just guess it to be 600-700 rpm.
Idling your engine at 700 or idling it at 1000 is not going to make one whit of difference to your engine.
It will just waste fuel, slobber more and stink and smoke longer when you finally get it off its butt and work it.


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## Ed Williams

Again, valuable info from an experienced diesel tractor operator.


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## marc_hanna

I always run my tractor at rated rpm. First of all, it ensures all the hydraulics are working at capacity and secondly, in the winter it gets the temperature up. In the summer after it’s warmed up, I’ll idle it down between tasks, but in the winter, I idle it 1,200-1,500 rpm to keep it warm


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## marc_hanna

I might also add that I treat my fuel with cetane booster and lubricity additive, so it runs very smoothly and has very little oil contamination. After a hundred hours of operation the oil looks almost as clean as when it first went in. A higher cetane number will reduce peak pressure in the cylinders and produce a more complete burn thereby reducing those ill effects.


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## XLENDI

I can only talk from medium duty diesel engines. Diesel engine are CI , engine operating temperature is critical to the life of a diesel engine . An engine like a human produces unwanted by products when running , we eat we crap, we drink we pee, we work we sweat, or should do.
no different from an engine. the temperature helps eliminate the by products, unwanted internal acidic gasses are vented to the atmosphere or plumbed back into the intake , you need temperature to get rid of these gases. For the oil to perform correctly it needs the correct temperature, this ensures all moving parts get the correct lubrication, the oil dumps most of the unwanted by products into the filter.( engines that also have a centrifuge filter , put normal filters to shame, when you clean no mess , just a nice layer of that is dry , scrape out and dump)
Excess idling can lead to cylinder glazing,( can be mild or a major) burnt injector tips, excess oil down inlet valve guide. If you notice you develop excess crank case pressure or wet exhaust check for blow by. If not bad , working the engine under load will normally fix this problem. Diesel engines are born to work and love it , 75% load at correct working temp and they love it, bursts up to 85% and the occasional 100% they are in heaven. Any ambient temperature above 25 c , to let engine idle for a few minutes will not hurt it , *NEVER* shut down an engine if he has been working hard, with out idle time , if working hard and quick shut down engine temp will increase and can possibly go above operating temp , if you re start quickly you can have a problem with piston pick. If turbo , for sure let idle for a few minutes as when you shut down , turbo does keep turning , but with out oil pressure. look after it like you look after yourself , If you do not eat clean food you die , if you do not shit you die , if you can not breath you die , if you can not piss you die , if you sweat and cannot cool you die, treat them like you would treat yourself and they will NOT let you down. Rudolf done the world a service when he invented the diesel engine, but he made it to run on peanut oil. ANY WAY TO ALL OUT THERE GOD BLESS , TIME TO THINK OF OTHERS THAT DO NOT HAVE WHAT WE ARE BLESSED WITH. A VERY SAFE CHRISTMAS TO ALL AND THE FAMILIES.


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