shut off truck or leave run?

Discussion in 'Trucks and Trailers' started by sirsweatsalot, Jan 22, 2003.


leave it run or shut it down

  1. leave it run

    12 vote(s)
  2. shut it down

    15 vote(s)
  1. sirsweatsalot

    sirsweatsalot LawnSite Senior Member
    from MN
    Messages: 296

    when you go to spray a lawn and your truck is diesel do you either shut it off or leave it run... saying it will take you 10-15min?
  2. bob

    bob LawnSite Platinum Member
    from DE
    Messages: 4,260

    Shut off.
  3. hosejockey2002

    hosejockey2002 LawnSite Bronze Member
    Messages: 1,195

    If truck has a turbo, idle for a couple of minutes to cool turbo and shut off.
  4. Bunton Guy

    Bunton Guy LawnSite Bronze Member
    Messages: 1,919

    leave her running. Nothing is going to be hurt by running her all day. A diesel will burn a quart of fuel if you let it idle for 10 hours. So if your stingy and dont want to burn 1 quart of fuel then shut it down. Usually dont need to let the turbo cool unless you are pulling near max payload for the truck. Even then if you have gone through some stop lights and had to sit at lights and stop signs your good to go nothing to worry about.
  5. brentsawyer

    brentsawyer LawnSite Senior Member
    Messages: 663

    A friend of my dads runs a tour bus company and several years ago before he had a full time mechanic, he started all of his buses and let them run the entire night when he left and temps were cold, he said that this kept internal parts loose and cost next to nothing in diesel fuel. Also, it is alot harder on the engine to stop and start it than anything else
  6. Randy J

    Randy J LawnSite Bronze Member
    Messages: 1,124

    I tend to let mine idle a lot, as mentioned, it costs minimal amounts of fuel. And it's well known that the greatest amount of wear occurs at startup of a vehicle. However, you have to be careful when letting diesels idle in cold weather. They can cool down so much that the combustion process is in-efficient leaving fuel in the cylinder. The fuel then washes down the cylinder wall, washing off protective oil, and diluting the oil in the crankcase. All diesel pickup manufacturers recommend against extended idling periods. For most, you can get an idle controler though. It's a simple switch that allows you to increase idle speed, so you can leave it idling with out harm.

  7. sirsweatsalot

    sirsweatsalot LawnSite Senior Member
    from MN
    Messages: 296

    in cold weather leaving it idle would be ok if it had a tank heater? right?
  8. Bunton Guy

    Bunton Guy LawnSite Bronze Member
    Messages: 1,919

    Randy I think that probelms are only on the older diesels with the fuel washing the oil off the cylinder. Personally my 01 F-350 PSD has a idle sensor when left idling for long periods it raises the RPM's just a few hundred to get some heat back into the motor and also in the cold mornings it automatically turns off the exhaust gate so that the engine will heat up quicker.
  9. Randy J

    Randy J LawnSite Bronze Member
    Messages: 1,124

    A tank heater won't help prevent fuel from washing down cylinders. It's not the temp of the fuel, it's the temp of the combustion chamber that matters. Ever notice that semis idling overnight are idling a little faster than normal? I wasn't aware newer Fords had the ability to automatically raise the idle. It needs to be around 1000+ rpm in order to keep cylinder temps high enough to prevent cylinder washdown.

  10. hoagie

    hoagie LawnSite Member
    Messages: 222

    There's a ton more info on this at

    Not only will it wash cylinder walls, the unburnt fuel will also build up on the exaust valve over time and eventually cause it to stick open :eek: This is "wet-stacking".

    Fords cold weather package does increase idle a little, but not enough to prevent wetstacking... in cold weather it needs to get up to 2000-2200 rpm. Get an auxillary idle controler(AIC). They're available direct from ford, but cheaper w/ some online sources.

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