Diesel warm up?

Discussion in 'Diesel powered automobiles' started by EVuser, Aug 10, 2011.

  1. EVuser

    EVuser Well-Known Member


    Is there any practicial reason for leaving a late model Power Stroke diesel in a 4X4 pick up engine idling?

    Case in point the owner starts it up in the morning (0630) and lets it idle for 5 to 15 minutes before driving. Outside temperature is mild 50-65.

    The 4X$ extra cab is empty, so no work to do other than moving itself and driver.
  2. seftonm

    seftonm Veteran Staff Member

    Only reason I can think of is that he's a wuss and needs warm air coming out of the vents before he spends any time in it. No practical mechanical reason to do so.
  3. 2RR2NV

    2RR2NV Ultimate Newbie

    actually, depending on which model it is, idling to get "heat" doesn't work real well. the coolant systems on a lot diesels are dang good and if the truck ain't working.....like towing, it actually cools off quite well and drops way below "operating" temp. had a good friend with a 3/4 ton Cummins. he let it idle for probably 30 mins and his truck WAS warm when he parked it. when he went out to leave, his windows were frosting all over.

    so personally, there is no real point except to prevent fuel gelling. at those temps? highly unlikely that THAT's happening either.
  4. Mendel Leisk

    Mendel Leisk Rapt Presence Staff Member

    I used to hitch a ride home with a guy with a big diesel pickup. Don't ask me what make/model. He would always start it up and let it run maybe 5 minutes, saying that's what it said to do in the Owners Manual. He wasn't sure either, how important it was, but figured to stick with the instruction.
  5. Gord

    Gord Super Moderator Staff Member

    I always start my diesel Honda up and go as soon as possible. It can't serve any good purpose to sit idling a cold engine (whether petrol, diesel). Waste of fuel.
  6. msirach

    msirach Well-Known Member

    People around here do it with diesel and gas engines. Convenience stores in the morning always have diesel trucks idling. I figured up on an older model V6 4.0L Ford, it costs 22.5 cents per minute idling at $3.75 per gallon. No, there isn't a good reason with modern lubricants to let a vehicle "warm-up."
  7. herm

    herm Well-Known Member

    One of the reasons diesels are so efficient is that they dont produce a lot waste heat..on the other hand idling it does not hurt the engine, unlike gasoline ICE.
  8. oilburner

    oilburner Active Member

    I always thought diesels needed warm engine oil so it doesn't fry in the turbo, but I have never heard of warming it being a problem. I know you can kill the turbo if you do not let it sit after driving. Turbo timers are great for that.
  9. vtec-e

    vtec-e Celtic MPG Warrior

    If you are driving economically there will be hardly any need to let the turbo cool down as it will already be cool-ish. On my drive home there is a hill i have to climb with a flat section before i turn in my gate. I coast the flat then engine brake the last bit to my gate. A bit of throttle in the gate (I know, i know but it's narrow and i don't want to hit the pillars!), a few seconds to let turbo slow down as i can hear it whining down after i reverse into my parking spot and then off.

    Regarding your first point about a warm engine to preserve the turbo? I can think of no reason that should be the case. Sure, gunning the engine from cold will cause problems down the line but, again, if you (not you personally:)) are driving economically you will not have this problem.
  10. dieselbeetle

    dieselbeetle Member

    I didn't look at most of the answers you received, just so you know. I also realize it's been about 3 months since your question. Never fear, evdriver. never fear.

    the fact is that older diesel trucks often need to be "plugged in" (referring to oil and engine block heaters) some time before starting. in some cases, even hours!

    i drive a small diesel car, so take it from me: if it's warm enough to start, it's warm enough to drive. with that said, it's recommended to keep the engine lower than 2500 rpms during this period of "coldness". really, i'd recommend this for any car regardless of fuel medium. it's just smart not to hot rod or drive too briskly before your car is warmed up.

    it's also important to realize that these guys who leave their pickups running for 15 minutes are the same people who leave them running when they do their grocery shopping. they're idiots. anyone who says, "it uses less fuel to idle than it does to restart" or another popular excuse, "i'm keeping it warm" are completely wrong and are largely the products of either ill information or lack of education. there's of course a nice way to educate your neighbors, friends and family. if for nothing else, do it because you appreciate being talked to this way! they're more likely to listen when you put a bit of sugar on top, yes?

    my car handbook in particular (can't imagine it being different for other diesels) recommends conservative driving during the car's warm up period as opposed to idling. this makes sense for the life of the car and the longevity of your fuel.

    when i first got my car i wasn't this savvy of course. i would let it idle for 20 minutes or so to warm up in winter. i'd get in and it sometimes would still be cold. now, i drive as recommended and it heats up in about 1/4 of the time.


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