Why do the big rigs idle all night long?

deadmandeadman Member Posts: 3
edited April 2014 in General
Does anybody know why some big rigs idle all night long and some don't? Is there a specific reason for this? Is it good for the rig? Any thoughts would be appreciated. Thanks--Deadman


  • hunter98hunter98 Member Posts: 273
    Well for one thing alot of time, is that when it is cold, it is good for it to run and keep heat built up. It also keeps the batteries charged up for Tv's, computers, fridges, lights, ect. Some of the newer ones are automatic startup and shutdown. They will when parked, cool down, shut down, and start and run for a specified period every say 3-4 hours. Some of the newest ones have generators that are automatic and very quiet. They actually circulate the oil and the coolent and function as a constant block heater as well. To keep them warmed up. A diesel is increadible efficient at idle. A 400 hp diesel engine will seem to use less fuel at idle than say a ford taurus. Actually three to ten times more efficent than a comparitive gas depending on the engines.

    Hope this Helps

  • jim4444jim4444 Member Posts: 124
    And those engines take a very long time to warm up after they have cooled down. It might be hard to believe but truckers will tell you it costs them more to shut the engine off than to keep it running, at least on a conventional one, ones with auto start every few hours to keep em warm sound like a good idea.
  • goo333goo333 Member Posts: 7
    In real cold tempertures diesel fuel will turn so thick it will not flow. In other cases the engine is running to run a refrig. cooling for the trailer.
  • ryanbabryanbab Member Posts: 7,240
    Diesel trucks also have a place to plug them in to keep em warm during the winter
  • roger350roger350 Member Posts: 157
    A friend who has relatives that farm in Iowa, says they leave their diesel tractors running from about Nov./Dec. through about March, non-stop. I've always heard that it was the cold start problems.
  • ryanbabryanbab Member Posts: 7,240
    wear and tear is another reason.

    Diesels are hard to start on cold mornings. At work we park our diesel forklifts inside then let them run all day outside.
  • deadmandeadman Member Posts: 3
    I agree and appreciate all the comments you all are providing. I believe that it is in some ways hard on a diesel no-matter what the temperature is-to start them. The reason I ask the question is that I see people all the time driving there 1 ton diesel pick-ups and cutting them off to run in the house or a store for one minute. I would carry an extra set of keys, lock the truck up, and let her run. Nothing I like to hear more than a diesel engine purring. I believe you lose a lot of efficiency in any vehicle you drive if your constantly turning it off and on, especially a diesel-as you have to worry about special charging systems, glow-plugs or internal heaters, and starters-all that cost a lot to replace.
    Keep the comments and ideas coming.
    Thanks, Deadman
  • cspauldingcspaulding Member Posts: 159
    Any reefer I've seen runs separately, not off the engine.

    Ether works good on cold mornings if no plug in is available, used it plenty of times on the semi.

  • ethuressonethuresson Member Posts: 55
    I have a 1.9L VW TDI diesel and it has had NO cold start issues whatsoever down to below zero F temps. Starts quicker, in fact, than my gas vehicles.

    I know it's no big rig, just wanted to share that some of the newer diesels do not have the issues associated with older oil burners. Fuel has not gelled, either, though I wouldn't want to go too low on temps for that one. Actually, fuel that is sent to the engine and not injected into the cylinders is sent back to the tank warmed up, thereby heating the fuel in the tank.

    New European diesels kick [non-permissible content removed]
  • vintnervintner Member Posts: 5
    All of the reasons stated apply,however as I have been driving them for a living the past ten years, I can tell you that more than anything else you leave it running for heater or air conditioning,it gets hot or cold real quick in those bunks. By the way,most diesel (truck)engines should be idled up a little.I lost a seal in a turbo (caterpillar) because I didnt know you were supposed to do this. I dont know if this applies to tractors,pickups etc.
  • michgndrmichgndr Member Posts: 160
    If you really want to understand how these engines work, you have to ride a Diesel cycle at least once.
  • cspauldingcspaulding Member Posts: 159
    are equipped with glow plugs, winter starting is not a problem. Most places that are cold enough for the fuel to gel sell a different type diesel in winter to help with that problem.

    Vintner's and other drivers got it right...they're left on to heat/cool the bunks and run accessories (TVs, Radios, etc)...try sleeping right next to a reefer that kicks in to cool the trailer...you'll know why accessories are helpful. Try sleeping in a sleeper (especially a coffin) and you'll know why heat/air is necessary; better yet, try two in a bunk.
  • 2t1a2t1a Member Posts: 7
    Several of the newer engines from each of the majors have an auto shutdown and restart function. The reasons to leave it running usually dealt with cabin comfort. If a person was going to doze off in the sleeper, they'd want some heat (or AC), either is going to need the engine and a fair amount of current for the fan.
    For example, the parasite load (alternator, A/C compressor) on an inner city bus can be as high as 80 hp. Granted, a sleeper is smaller, but you get the idea.
    More recently, some sleeper cabs have Laptop ports, TV's, even satellite systems, all requiring electrical power. The auto shut down and restart functions typically monitor all of the key parameters (voltage, cabin temp, outside temp) and run or shut off the engine accordingly.

    At normal temperatures (above, 20 below or something, I don't remember), idling the engine can cause more harm than good, mainly fouling the injectors, screwing up the rings, that sort of thing. They don't produce enough heat at idle to keep things from getting gummed up. At really cold temperatures, these disadvantages may be the lesser of two evils. Either way, a big diesel (Cat, Cummins, Detroit, etc.) is generally meant to be run at 50-80 percent of rated power for several thousand hours between overhauls. A 250hp engine in a car, by contrast, will generally only run at 50 hp or less at 70mph - 20% of rated power. FWIW, this accounts for some of the cost difference between an "industrial grade" diesel (Cummins, Nav, - too soon to tell about the Isuzu) and an automobile derived engine. Given proper maintenance, and some actual use (pulling a camper, horse trailer, etc) either diesel ought to be good for 300,000 - 400,000 miles before an overhaul, and another similar amount after. If you use it to haul kids to soccer practice, it won't go nearly that far. However, with good care 500,000 miles plus before an overhaul is not out of reach (IMO). Some of the 12-15 liter trucks will go close to 1,000,000 miles before an overhaul. The automotive V8s are, by comparison, disposable. Yes, you might get 300,000 miles from one, but if you run it fairly hard, you're probably looking at more like 150,000. This is OK, because the body hardware often gives it up at 200,000 so nobody notices.

    Anyway, the main reason the big trucks idle all night is operator comfort, and maybe the sound :-)
  • oldharryoldharry Member Posts: 413
    An aquantance that works on diesels for the railroad, says they never shut them down except for major repairs. Expansion and contraction causes oil and water leaks if they are alowed to cool.

  • deadmandeadman Member Posts: 3
    Someone on another board I visit often posted that the cummins 6 cylinder (1 ton dodge) diesel doesn't have glowplugs, it has some sort of internal heater system used before start-up. Is this true? Is this difficult to replace if it goes out? My dad owns a dodge cummins diesel duelly and we love it, I'm actually thinking of getting one for my self.

    Deadman Pulling
  • 2t1a2t1a Member Posts: 7
    No glow plugs on the Cummins. They use a heater in the intake manifold instead.
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