Warm up cars, or just go?

Discussion in 'Shop Talk' started by DJ in WA, Nov 1, 2006.

  1. DJ in WA

    DJ in WA Well-Known Member Supporter

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    Somebody at work said that letting cars idle to warm up in winter is hard on the engine. What do you think? I suppose the other issue is safety and having a defroster work while you're moving.
     
  2. mohillbilly

    mohillbilly Well-Known Member

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    On a cold morning if there is no frost/ice/snow on the glass, I start my vehicle, let it warm up about a minute or so to get the fluids moving, then i drive the car slowly and easily till the temp starts to rise on the gauge.. After the temp is up to around where it should be, then i alow the vehicle to reach cruising speeds down the highway. but remember this, on those REALLY cold mornings/days, your engine may be warm and the oli flowing good, but the grease in your wheel bearings and differntials is still cold!!!! so it is best to take it easy for a while to let things flow good. Synthetic oils and greases are more foregiving in the cold, but still best to let things gget warmed up a bit by driving a bit slowly... Just my thoughts on the subject, i am sure others will have there own ideas on this
     

  3. vallyfarm

    vallyfarm Well-Known Member

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    mohillbilly gave the best advice there is. Older cars with a carb liked to warm up because the choke could make the car stall or lose power at acceleration. Fuel injected cars have no problem. If the glass is clear, give her a minute to get all the fluids circulating, and just go easy until the engine is up to proper temp. This is more for the tranny visc. mor than the engine. Mike
     
  4. Columbia,SC.

    Columbia,SC. Thats MR. Redneck to you

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    Think about this,, you are in a tent, no heat. The sun wakes you up and you jump up and start running/jogging in the *30 temp,, I would go about 100' them cramp up, then I would struggle for 2 days from pains...I always warm up the car/truck for at least 2 mins. before I ease out the long driveway. I bet this guy who offered the advice has a new car with a 4 year waranty!
     
  5. mohillbilly

    mohillbilly Well-Known Member

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    Yep, even new cars need the same treatment as the older ones......unless you got a rental or a leased vehicle, then drive it like you stole it!!!!! LOL!!!
     
  6. rambler

    rambler Well-Known Member Supporter

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    It's not a problem until the tires go 'thump' when you roll, because the rubber is frozen. About 15 or 20 below that kicks in. :)

    Generally let it run a few seconds to get the oil pressure up - same as when it's warm out. As long as you are using the proper winter fluids, that's about it.

    Diesel, or turbo, or such has different requirements, but a general common gasoline engine, warming it up over a minute or so is generally for the people inside, not for the machine itself.

    --->Paul
     
  7. Northman

    Northman Well-Known Member

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    I'm a ASE certified Master Auto tech , ASE certified Med/heavy Diesel engines, Ford Certified Diesel specialist. plus over 15 years wrenching professionally. Like rambler said other than turbocharged engines giving the engine enough time to circulate the oil is all that is needed.

    There's absolutely no problem letting it warm up longer it's your gas your burnin'
     
  8. Esteban29304

    Esteban29304 Well-Known Member

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    PLUS, idling= ZERO MPG
     
  9. blufford

    blufford Well-Known Member Supporter

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    If you warm it up, do it while its still parked. Theres nothing worse than pulling on the highway and someone is driving real slow until their car warms up. Dangerous too!
     
  10. Beeman

    Beeman Well-Known Member

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    Start it and go. The worst thing is short trips, long periods of not being used and not running highway speeds and getting everything up to temp.
     
  11. agmantoo

    agmantoo agmantoo Supporter

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    What about the thermostat being closed due to cold and then revving the engine and creating high pressure from the water pump and no place for the coolant to go other than through the heater core rupturing same? I like for my thermostat to atleast start to open.
     
  12. Northman

    Northman Well-Known Member

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    If your waterpump can pump enough pressure past the bypass to blow your heater core chances are it is because of neglect of the cooling system.

    when checking your coolant check for freeze protection, contamination(color), and use your multimeter to check if system is producing voltage.
    This voltage pits metals making them weak.

    neglected coolant can also destroy gaskets and seals.

    modern automobiles can last an incredibly long time if maintained regularly.

    Needless to say I'm not of the mind "if it isn't broke don't fix it. I believe in following the factory recommended service intervals. preventitive maintenance.
     
  13. mohillbilly

    mohillbilly Well-Known Member

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    Yep, just as i thought, as always, everyone has there own opinion........

    I dont care who ya are, if your car is COLD, It is better to drive it easily after a short warm up to let the fluids flow good, than to drive it as you would in the summer time...thats why i have a truck with almost 400,000 miles on it, 3 318 Dodges with over 300.000 miles on them and a newer dodge intrepid with 100,000 problem free miles on them.......take care of them, drive them like you are a grandma, and to hell with the traffic behind you.... I drive my vehicles with respect and with the idea that , they always cost me money no matter what, so i might as well get the most out of them....
     
  14. skruzich

    skruzich Well-Known Member

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    I agree mo, You can get away with it on a newer car, but if you drive old cars like i do, your more likely to sling a rod if you try driving as soon as you start it on a cold morning. give the poor ole gal time to warm up. If you don't she's going to leave ya.

    this falls into the category of like changing oil every 3000 miles. The dealers say you don't have to do it but every 6000 but they are going to tell you that cause theywant you to buy a new car every so many years.
    I just did a compression test on my s-10 with 340k miles on the motor and get 150 psi on every cylinder.
     
  15. Beeman

    Beeman Well-Known Member

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    Generally pressure in a cooling system is created by heat and expansion more than the water pump which is just a circulation pump. Besides the radiator cap relieves pressure if the engine is cold or hot so the system can only pressurize to what the cap allows as it is the blowoff valve.
     
  16. Herb

    Herb Well-Known Member

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    I like to let my truck warm up in colder weather. I haven't noticed an appreciable drop in gas mileage by letting it warm up. I was averaging 19.53 MPG for the month of September and I was averaging 19.48 MPG for October. And yes I may have OCD.
     
  17. Oilpatch197

    Oilpatch197 Well-Known Member

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    I've heard perhaps wives tales that if it's really cold outside you need to let your engine warm up for a tad bit, the reasoning is that your pistons could crack going from lets say -10 to +190 from the stress.

    So just popping the starter and going in really cold weather is a silly Ideal.

    I am going to try some things this winter, one of them is installing a "tank type" engine coolant heater, this should keep the engine fairly warm and less Idling time on the coldest of mornings, I may consider a battery heater also, since batteries love to fail in very cold weather....
     
  18. skruzich

    skruzich Well-Known Member

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    Just go get one of those oil dipstick heaters that hook to the battery. that will keep your engine warm, and the heat from the engine will also warm the compartment and keep the battery warm enough usually.
     
  19. Beeman

    Beeman Well-Known Member

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    Cracked pistons? Pistons today are made with hypereutectic aluminium, they are sized with anly .001-.002" clearance to the cyl. walls. They don't change very much from heat.
    Warming your engine with a block heater or a dipstick heater works well, biggest thing it does is keep oil warm and thin. Biggest problem is people are "lost in the past" with automotive knowledge and tend to use much heavier grade oils than necessary or recommended.
     
  20. wraithe

    wraithe Member

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    My little Jeep diesel has a block heater, which I love dearly when it's cold outside. Here's what I know from 20 years of operating nuclear submarine engine rooms. When bringing a turbine up from cold iron, it is very slowly spun up to allow the metals to slowly equalize temps and minimize stresses.

    Here's how this ties into this discussion, when your engine is cold, the warm up time is dependent on how much power you force it to make. If you step on the gas and accelerate hard to high speeds, you force the engine to warm up quickly and increase stress and wear. If you accelerate slowly and use reduced speeds, the warm up is slower and less wear.

    If you let it sit and idle though, there's more blow by past the rings, more water vapor condenses in the oil and more acids form which cause rust and corrosion, if you don't get the engine warm enough every once in a while to boil off the water. So it's a balance.

    I figure the engineers that developed the start up procedures for the engine rooms that I worked in were pretty good, since they lasted for 30 to 40 years, running 24 hours a day, 7 days a week in a lot of cases. JMHO, YMMV