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Do You Turn On AC/Heat At Start Of The Engine?

Discussion in 'Technical Chat' started by tim920, Jul 7, 2010.

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Heat/Ac on at start of engine?

Poll closed Apr 1, 2013.
  1. Yes

    88 vote(s)
    51.8%
  2. No

    82 vote(s)
    48.2%
  1. Jul 7, 2010 at 6:12 AM
    #1
    tim920

    tim920 [OP] Never seen Forest Gump

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    I have an auto starter and I use it mostly for the winter. I usually have the heat set at the second out of four, so that when I start up my car the snow will be melted after 10 minutes or so.

    And now that it's summer I turn on my AC right when I manually start my car.

    How long after you let your car run before you turn on heat/ac?

    Is it a bad thing for the engine or other components? If so....why/how?
     
  2. Jul 7, 2010 at 6:16 AM
    #2
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Moderator

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    I keep it off until the engine fires up. THen turn it on. A couple things.....The Compressor wont engage until the engine fires up, however, Im "Old School".
     
  3. Jul 7, 2010 at 6:24 AM
    #3
    larryde09

    larryde09 Well-Known Member

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    I keep the AC off until after startup. For me it's a parts-preservation thing...it is an extra unnecessary load on the engine at startup. The engine cranks harder and longer which puts a strain on parts, particularly the starter.

    In the winter, I typically have the heat on when it's warming up. But if I drive it immediately, I'll keep it off until the engine warms up.
     
  4. Jul 7, 2010 at 6:27 AM
    #4
    jesseunvoas

    jesseunvoas Well-Known Member

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    it's not bad for you truck the heat won't come until it's warms up anyways and a/c comes on with defrost
     
  5. Jul 7, 2010 at 6:27 AM
    #5
    tim920

    tim920 [OP] Never seen Forest Gump

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    Thanks guys! Great inputs.
     
  6. Jul 7, 2010 at 6:32 AM
    #6
    Janster

    Janster Old & Forgetful

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    I don't even think about it.

    If its on when I shut the truck off, it's on when I start it. I don't go outta my way to start it or shut it off. The truck can handle it.... if it can't, then shame on Toyota.
     
  7. Jul 7, 2010 at 6:35 AM
    #7
    AeroCooper

    AeroCooper Half the strength of ten (microscopic men)

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    Even if the A/C light is off, it is actually still on every time defrost is on?
     
  8. Jul 7, 2010 at 6:47 AM
    #8
    Zombie Runner

    Zombie Runner Are these black helicopters for me?

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    ^yup. there is a mod to "fix" it though
     
  9. Jul 7, 2010 at 6:47 AM
    #9
    middiedefense

    middiedefense like a boss

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    Yea I usually don't go out of my way to ensure the AC is off before start up. I have a buddy that freaks out about this kinda stuff but I figure its not his POS S-10 so it can handle it.
     
  10. Jul 7, 2010 at 6:52 AM
    #10
    tim920

    tim920 [OP] Never seen Forest Gump

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    ^lol My girlfriend is somewhat the same. She makes sure my radio is off before we leave the car. OCD? :D
     
  11. Jul 7, 2010 at 6:55 AM
    #11
    AeroCooper

    AeroCooper Half the strength of ten (microscopic men)

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    I guess that explains why my windshield keeps freezing up when it's on defrost mode, even when it's 80 degrees out (I like the indirect air flow)? :mad:

    I actually took my temp controls apart the other day trying to get it to stop turning the A/C on when it is turned all the way to cool, but no joy, I couldn't get deep enough into it, and gave it up since I was sweating my ballz off at the time.
     
  12. Jul 7, 2010 at 7:33 AM
    #12
    skytower

    skytower Well-Known Member

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    Hitch and wiring, aux back-up light, rear strobe lights, radio and underseat sub.
    Ac with defrost is to remove moisture from the air.
    Starting with everything running will not hurt anything. Accesories are disconnected while starting. Notice that the headlights, radio and fan cut off while starting?
    Excessive idling will cause some issues (use severe oil change recommendations). As long as you have a 20min drive after the engine reaches normal temp, you shouldn't have any battery issues.
    Short trips combimned with excessive idling in winter are battery eaters. Keep idling to 10 min or less.
     
  13. Jul 7, 2010 at 7:53 AM
    #13
    rob1

    rob1 Well-Known Member

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    x2....same here
     
  14. Jul 7, 2010 at 8:11 AM
    #14
    AeroCooper

    AeroCooper Half the strength of ten (microscopic men)

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    Agree excessive idling is bad for the engine, but the battery will charge just fine, regardless if you are idling or driving. It will charge more as the rpm's increase though.
     
  15. Jul 7, 2010 at 8:14 AM
    #15
    larryde09

    larryde09 Well-Known Member

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    Yes, this is how the defroster works...the AC dries the air, then the dry air is blown onto the glass picking up the moisture off the glass.

    I haven't seen this mod, but I'm not sure it's the best idea...kind of defeats the purpose of a defroster. It can't "defrost" if your blowing moist air onto the glass, it probably makes it worse in some conditions.


    The AC is the only thing I turn off when I shut the engine off...the electrical loads are negligible compared to the AC compressor...no need to shut them down.
     
  16. Jul 7, 2010 at 8:25 AM
    #16
    AeroCooper

    AeroCooper Half the strength of ten (microscopic men)

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    I haven't had the truck long enough to try the defroster in the winter yet, but in the summer it is a pain in the butt because on a warm dry day it actually fogs the windshield up and then the fog freezes unless you turn the heater on or keep running the wipers.
    Not liking the A/C linked defroster at all.
     
  17. Jul 7, 2010 at 8:39 AM
    #17
    Oskie_78

    Oskie_78 Well-Known Member

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    I shut off my a/c before turning off my truck and start the a/c right after I start the truck.
     
  18. Jul 7, 2010 at 9:29 AM
    #18
    gfiber

    gfiber Well-Known Member

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    Generally most modern vehicles the accessories are disconnected during the actual starter motor running process. So it really should not matter if any A/C, Heat, Radio was on to the battery when you start the car. Now if you tend to sit there for a few minutes and have a questionable battery then you could run it down to where it won't start.
     
  19. Jul 7, 2010 at 10:16 AM
    #19
    skytower

    skytower Well-Known Member

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    The more accessories you have on=less for the battery. Cold batteries have less reserve capacity. The battery will charge, but will take much longer at idle.

    Also notice that you can't run recirc and defrost at the same time. That prevents fogging too.

    Why would you need defrost in the summer?
     
  20. Jul 7, 2010 at 10:23 AM
    #20
    AeroCooper

    AeroCooper Half the strength of ten (microscopic men)

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    Sometimes I just like the indirect air from the defrost vent with the temp control turned down, it allows 'fresh' air without having it blowing right on you. Just a preference.
     

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