Is idling really bad for a diesel?

[SixPac]

I guess a misconception I had when I bought my diesel was that prolonged iding would not hurt it. The "Truckers" do it. I know I've read threads on this in the past, but now find myself worrying when I get in rush hour traffic, sometimes not moving for long periods of time.



Can some of you help me with a couple questions?



How long would be too long to idle?

Is it harder on a diesel to idle than a gas engine?

Why does it hurt a diesel to idle?

Would I let it idle in the Winter time to warm up?



I'm slowly leaning more about my truck and this forum has been most informative. I appreciate all the help!



Thank you,



Bob

 

[Jumbo Jet]

I don't know exactly how bad it is, but I know my truck will NOT warm up in cold weather while idling. I've read where people with an exhaust brake use it to help the warm up process.

 

[Max Wedge]

The problem with Idling is the cylinder temps will drop to a level that not all the fuel will get burnt, and the raw fuel will "wash" the cylinder walls out--remove oil film--bad for the rings, and it contaminates the oil.



Big rigs do it--mostly because when they jump out on the road they are driving for hours and it will burn up all the contaminates in the oil--usually we don't drive that long. Second they (Big Rigs)

will have a high idle adjustment in the cab that will bring the RPM's up to a level that the fuel is burnt. It won't hurt it to idle for 15 to 20 minutes as long as you are not parked up against a wall in the middle of summer with the air on.



Max

 

[DNelson]

On a "big rig", even with the idle set up, the water temp typically drops to maybe 130-140, lower in the winter when you're trying to keep your a** warm in the sleeper - even with a grill cover on. I wonder if the same damage that happens with our diesels doesn't occur on the big engines as well - it's just that there's so much more material, better specs, and regular tear-downs, that it doesn't become a problem.



Don

 

[Archive]

Page 117 of my '99 owners manual says...



Engine Idling



Avoid prolonged idling. Long periods of idling may be harmful to your engine because combustion chamber temperatures can drop so low that the fuel may not burn completely. Incomplete combustion allows carbon and varnish to form on piston rings and injector nozzles. Also, the unburned fuel can enter the crankcase, diluting the oil and causing rapid wear to the engine.



Stopping the Engine



Idle the engine for a few minutes before routine shutdown. After full load operation, idle the engine 3 to 5 minutes before shutting it down. This idle period will allow the lubricating oil and coolant to carry excess heat away from the combustion chamber, bearings, internal components, and turbocharger. This is especially important for turbocharged engines, like your Turbo Ram.



Hope this helps!

 

[EMDDIESEL]

Over the road trucks have high idlers and also have MUCH larger oil capacities to deal with contaminants. They also run hotter in the winter with grill covers. Locomotives idle for WEEKS at a time with no problem.

I added an adjustable High Idler to my truck which will allow me to raise my idle RPM anywhere from normal up to 1,500 RPM to warm the truck up faster.

 

[JohnE]

All the electronic controled diesels have a winter idle setting that bumps the rpm up over 1,100

Many do not have any preheat (glow plugs or grids) so cold winter starting is a no-no. The better option for them is to get a dual Webasto unit. It has an air furnace to warm the sleeper/cab & a water unit for the engine.



I was talking to the diesel mechanic at my local Dodge (& Ford) dealership. He doesn't get chance to work on many diesels, especially the Cummins. The biggest single problem on the 24 valve is bent push rods from carboned valves due to extended idle. It gets very cold here in the winter.



I drop my truck into drive and set the parking brake. The load warms the engine and trany very quickly.



A Webasto or Espar is in my future.



cheers;



John

 

[FCrawford]

I have the electronic idle unit installed (the one fromn Canada) and use it in winter and summer. It keeps the oil pressure up. I am in remote areas of the country at oil sites and can not get to a motel and have no choice except to idle the truck. I have 180,000 miles on the truck which is 22 months old and is doing well so far (I hope).

 

[Bad340fish]

My work truck in an International 4700 with the DT466E motor in it. By no means is it a big rig motor but it has no preheat either. Unplugged it fires instantly even below 20*. It also has an Electronic Idle/Cruise feature. The truck can be idled at any RPM just by holding a button down untill you reach the desired idle. Next to those controls is a wanrning labe IN COLD WEATHER OPERATION MAINTAIN MINUMUM 1250RPM IDLE SPEED TO AVOID SEVERE ENGINE DAMAGE. I leave the truck running all day, when I jump out I hit the idle control and bring it up to 1000 for the summertime. It doesn't always work though lol so I let it idle for 30 minutes and it was smoking when I came back outside... stinky blue smoke. Answered my idle question right there

Clark

 

[exfuzz01]

idling of diesel

I was informed by the Power Shop in Enumclaw. . that when idling with the trans. in park... . fluid is NOT circulating through the transmission... They advise setting the parking brake with the shifter in neutral. Is this true?



01 Ram, QC, A/T, tow/camper pack, guages, nerf bars, liner, stock otherwise.

 

[Archive]

exfuzz... if you are looking for a second opinion, why not call or email BillK or Piers? I am sure they would not mind a few questions...

 

[danandamy]

ok, ok, I'm guilty

Sometimes I leave my truck idling quite a bit. You think you're gonna just run in and out and then someone catches you. Also, when we're on the road and have to stop and eat, we have to leave the truck running with the ac on for the dogs. This is one of the reasons I change the oil a little more often then most folks (every 3-4k).

 

[David Oxland]

One of the reasons for not idling is that, particularly in cold temps when it is considered desirable, the engine ticking over at 700 rpm has a poor start of injection, which coupled with not very vigorous turbulence, allows penetration of poorly atomized fuel onto the cylinder walls. Result carbonized rings and lube quality degraded. Also our Cummins have monster sized charge air coolers which at idle and in cold conditions will be just plain cold. This makes for cold induction air which doesn't help atomization. Hot induction air promotes good atomization in diesels as well gas jobs. This certainly works to our disadvantage at low load. The truth is. Diesels love hot air for combustion and with the turbochargers we have, density of air is not nearly so much of an issue.

 

[Sky]

I was at a party about a year ago and some girl and her boyfriend had a CTD idleing in the driveway for like 3 hrs+ I asked why is your truck running (I had to ask I felt sorry for the CTD ) She said its a diesel I let it run for hours all the time. I almost fell over. I told her that is bad for it. But she knew everything ya know. So it sat there for about 5 hrs idleing. I cant see the logic at all in that? Are people really that lazy and stupid???

 

[SixPac]

Originally posted by David Oxland

One of the reasons for not idling is that, particularly in cold temps when it is considered desirable, the engine ticking over at 700 rpm has a poor start of injection, which coupled with not very vigorous turbulence, allows penetration of poorly atomized fuel onto the cylinder walls. Result carbonized rings and lube quality degraded. Also our Cummins have monster sized charge air coolers which at idle and in cold conditions will be just plain cold. This makes for cold induction air which doesn't help atomization. Hot induction air promotes good atomization in diesels as well gas jobs. This certainly works to our disadvantage at low load. The truth is. Diesels love hot air for combustion and with the turbochargers we have, density of air is not nearly so much of an issue.

David, how then do I get my diesel warm in the winter? Just drive it cold? Will normal "city" driving warm it up?



Sixpac

 

[Archive]

SixPac... Start your engine, allow it to idle a minute or so, the oil pressure is up, and drive very gently... like a little old lady going to church on Sunday!



I use my exhaust brake... I fire up the engine, wait for the oil pressure gauge to show a good reading, the flip on the e brake. The backpressure helps to warm it up. Then, I take off slowly to let the other fluids warm up a bit.



Once you feel everything is warmed up, "Drive it like ya stole it!"

 

[Pat_in_Utah]

Sixpac: I can't wait to try my block heater in the winter! Anyone have any idea of elctric costs of doing this - daily, monthly... ?



Pat

 

[Max Wedge]

Originally posted by Pat_in_Utah

Sixpac: I can't wait to try my block heater in the winter! Anyone have any idea of elctric costs of doing this - daily, monthly... ?



Pat

Pat, here in Ohio it doesn't get nearly as cold as it doues for you guys, but I plugged mine in every night, just so that keeps the block and oil warm--cold starting is where you will get the most wear on any internal combustion engine. I bought a "cheap" timer at WalMart for about $5. 00 and I have it come on about 3 hours before I leave for work--Thats means it comes on about 6:00 AM -- never really hurt the electric bill, that I know of. You don't need it on all night long, unless it is seriously cold out.

Max

 

[David Oxland]

Sixpac,

It's a bit of a wrestle but I feel the best arrangement is to try to get some light load on as soon as your confident that lube has circulated to all the moving bits. Max time is probably less than a minute. Light load can be moving out of the drive way, lights and non aggressive driving or any electrical load such as lights, fans heated mirrors, AC if you can get it to run. The exhaust brake seems to be ideal just get moving and make the beast begin to work a bit and get the combustion temps on their way up. I know I'm not very comfortable with driving only a block or so and hammering up to highway speed but a balance is also important. I don't know much about automatic transmissions but the idea of slipping into gear and idling with the brake on seems ideal if no harm is done.

Large engine builders, Marine and Stationery now want light load applied to their engines within a few minutes of startup.



Sometimes I think we need to rethink the reasons for "slow warm up"



They were:

in the old days of oils with a low viscosity index Oils sometimes in frigid weather would not arrive at needed places for a long minute or so. Multi-vis oils have helped in that regard a lot.

in the old days cast iron blocks and cylinder heads and sealing arrangements of these mated parts were subject to distortion if heated aggressively from cold. That's not so much of a problem now either.



Some times when you hear of vehicles in the Artic or even southern regions being left to idle all night or for a few days is because they just don't have the starting arrangements, compressed air, heat, prelubing or electrical ability to get them going. The lube oil analysis will tell the story. Often when you see an engine commence work after a long idle they will blow all sorts of stuff, blue from lube oil, pale blue from unburned fuel, black from carbonized fuel, for a while. Admittedly some of these engines will be in hard shape but many not. 2-strokes are particularly prone to fouling in the intake around in the intake ports and trunking after long idling periods and will blow great clouds until they clear out as EMD would probably tell you.



I've got a Horton fan clutch and I think that not having the fan drawing a load after start up is actually a disadvantage during warmup because it's lost load there fore smaller injections and heating value applied in the cylinder. Hope this helps

David

 

[Deezal Man]

Sixpac,



Aside from rigs having idle controls, larger oil capacities, bla, bla, bla... Most guys don't own em... so they don't care how long it idles.



And I doubt most people know its bad to idle a diesel for extended periods. How many of us would... if not for the sticker/manual??



As to your question, A diesel will not really warm up @ idle. Best to put it under a normal driving load. Block half the radiator and plug the heater into a morning timer. And lastly, accept the fact that your not driving a gasser.



Some guys think you have to crawl out of your driveway for the first 5 miles... IF that makes em feel good. . wonderful. Other than TDR members, most diesel see about 30 seconds to a minute of warm-up before they move the days load. Considering how long they last in that environment. . I wouldn't worry about driving it normal till it warms up.



Pulling a trailer, I would agree additional warm-up is a good idea.



As always, OMO