Fans always on? Good or bad idea

Posted by rtrocket59, Dec 26, 2012
Maintenance & Repairs - Oil choices, timing belt, setting timing, CV boot replacement, alternator servicing, fuse/relay checks, and other basic maintenance, repair and diagnosis discussions.

  1. rtrocket59

    rtrocket59 Proven Member

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    Rockaway, New_Jersey
    My 2g runs at 205° according to my dsmlink. I replaced the fans, radiator, thermostat (mishimoto 160°) and hoses and she still runs hot. I activated the fans always on through dsmlink and now it runs between 180-160° (traffic and idle). Would keeping them on be smart?
    #1
  2. 007jimmy

    007jimmy Proven Member

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    Levittown, Pennsylvania
    205 is normal. Fans are usually set to come on around 210*. Why are you running a low temp thermostat? It doesnt help with cooling/overheating any better then stock. If you are worried about your coolant temp, set link to throw a CEL at 217-220* to see if it gets higher then the stock fan settings. Running such a low thermostat can play hell with fuel trims and take the car longer to get into closed loop.
    Fans are only good for idle conditions and do nothing while driving. If you dont need them on all the time then keep them on the stock settings. If you overheat then you have bigger problems to worry anout.
    #2
  3. Mischif

    Mischif Proven Member

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    El Paso, Texas
    I have both my fans wired to a switch. I wind up leaving them both on all the time. As long as its not covering up a problem in your cooling system then its okay to leave them on.
    #3
  4. TopGun8818

    TopGun8818 Proven Member

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    San Jose, California
    You'll be fine leaving them on - I have the fan mod where they both come on at the same time. What's your concern in terms of leaving them on?
    #4
  5. rtrocket59

    rtrocket59 Proven Member

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    Rockaway, New_Jersey
    I'm using a low temp thermostat because I wanted the car to run cooler but it clearly didn't do much. How does it effect the fuel trims?

    I heard leaving them on could cause damage to the fan. Didn't really believe this but I wanted to double check on here.
    #5
  6. sidewaystsi

    sidewaystsi Proven Member

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    st. germain, Wisconsin
    Listen to the man.Having fans on all the time is only going to put an unnecessary drain on the battery/charging system. One reason engines and many other pieces of machinery for that matter operate just over the 200* mark is to evaporate moisture that forms inside them.Moisture causes rust/corrosion..we no like that kind.:thumb:
    And if i remember correctly the fuel trims will not show change until the coolant temp is above 186?or something around there
    #6
  7. rtrocket59

    rtrocket59 Proven Member

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    Rockaway, New_Jersey
    Seems like running a colder thermostat really isn't a bad idea. I'm going to deactivate the fan always on control and just offset the coolant temp by 15* to have the fans go on at 190* rather than when they come on at 206*
    #7
  8. ChiTownHussla

    ChiTownHussla Proven Member

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    Chicago, Illinois
    running cooler will not allow the car to go into closed loop
    #8
  9. dsmcurse

    dsmcurse Proven Member

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    Pasco, Washington
    Fans on all the time will put a extra work load on your altanator.
    #9
  10. TopGun8818

    TopGun8818 Proven Member

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    San Jose, California
    I would much rather replace an alternator which comes with a warranty then having to rebuild/replace a head due to it overheating. I take that this is a temporary fix and not permanent solution correct? I too had really bad overheating issues and have replaced and added pretty everything to help the car run cooler (mishimoto aluminum rad w/electric fan kit, water wetter, low temp thermostat, fans re-wired etc.) It greatly helped but I still experience overheating when the weather reaches 95* plus here in California. However, I usually put the heat on full blast and roll the windows down which grealty helps. Search overheating issues and you will be provided with a ton of usefull information to further assist you.
    #10
  11. c2ypt1c

    c2ypt1c Proven Member

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    Southern, California
    The only thing about this is that the ecu will pull a degree of timing at (a perceived) 206*. To counter this, you can globally raise timing, which, in my opinion, is a sloppy workaround. I really don't see why ecmtuning won't incorporate a custom parameter fan control function based on coolant temp, and this is really the only complaint I have with link.

    In my case, if I leave the fans full on, my temps drop to about 160*. If I leave it up to the ecu, I'll see upwards of 220*...it's dangerous to keep activating and deactivating the fans while trying to drive. More reason to incorporate fan control.
    #11
  12. sidewaystsi

    sidewaystsi Proven Member

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    st. germain, Wisconsin
    Well heres a no brainer(myself included)Any heat shielding/wrap on the manifold,turbocharger,or downpipe?If not covering those items with something will immensely help from baking the radiatior,block,and head.
    #12
  13. Kapok6

    Kapok6 Proven Member

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    Fort Worth, Texas
    I'm still trying to figure out what's wrong with 206*...
    #13
  14. finesse49ers

    finesse49ers Proven Member

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    Queens, New_York
    Great note. Include myself on this. Over this winter I'm going to have some kind of heatshield fabbed up around the exhaust manifold as my GSX needs all the help it can get with dropping the temp.
    #14
  15. blizz99

    blizz99 Proven Member

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    Browns Mills, New_Jersey
    I believe the ECU pulls timing at 206*
    #15
  16. rtrocket59

    rtrocket59 Proven Member

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    Rockaway, New_Jersey
    I am replacing all of those components soon but I definitely will once the build is completed.
    #16
  17. Kapok6

    Kapok6 Proven Member

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    Fort Worth, Texas
    I am having a hard time believe that dsms are not supposed to run at 206.

    Can anybody cite an FSM that states timing is pulled at 206+ or cite the ECU code that states this, or is it more dsm myth?
    #17
  18. c2ypt1c

    c2ypt1c Proven Member

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    Southern, California
    2g's pull timing at 206*
    important2gcoolantpoints [ECMTuning - wiki]

    not sure if 1g's do the same, but one would think so...
    #18
  19. Kapok6

    Kapok6 Proven Member

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    Fort Worth, Texas
    Thanks for the info.

    No, it's not the same for 1g's.

    Quoted from a conversation I had with an individual who works with the coding of 1g ecu's:

    "and there you have it
    it doens't even pull 1 degree
    it actually adds timing when its cold
    and goes to a 0 when its warm

    Code:
    13755  FE98             ;****************************************************************
    13756  FE98             ;
    13757  FE98             ; Interpolated from ect, used in timing advance calculations
    13758  FE98             ;
    13759  FE98             ;       $81 =  1 deg advance
    13760  FE98             ;       $80 =  0 deg
    13761  FE98             ;       $7f = -1 deg advance
    13762  FE98             ;
    13763  FE98             ;****************************************************************
    13764  FE98 80 80 80 80 L2020       .byte   $80, $80, $80, $80, $80, $84, $88, $8b      
    13764  FE9C 80 84 88 8B[code]
    
    $80 is the focal point of 0
    
     anything higher is +
    anything lower is -
    its hex for 128
    the only time timing is retarded is based on the IAT
    NOT the ect"
    #19
  20. rough

    rough Proven Member

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    I would check your hoses for collapsing. Rev the motor up by hand and see if the top and lower radiator hose sucks itself in.
    #20
  21. miguelmcv

    miguelmcv Proven Member

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    Los Altos Hills, California
    Well, all the post are good, but I never see any one mention about air duct.

    Making a nice air duct will help tons, and will run colder, now the low temperature thermostat will help but not much, unless you have a good air duct, if you don't have it, then that thermostat will not help as it should, because once the thermostat opens, the fans will not be ON and will not be able to cool it down as it should, it will cool only by the air that is coming from the front.

    Just Off set in link and play with it, if you see getting kind of hot, then adjust the off set a little more and you should be OK.
    #21
  22. Luisito

    Luisito Proven Member

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    Coral Springs, Florida
    My cars runs at the same temperature and it has never given me a problem. When I'm in the city I like to have both fans turned on since it get real hot here in Florida. But if I'm on the freeway I let one fan do its job. Heat shields and wrapping really help, and if you want to go crazy you can always fabricate some custom air ducts.
    #22
  23. Number1dad

    Number1dad Proven Member

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    Magnolia, North_Carolina
    I had mine the same and never had a problem.
    #23
  24. dsmspickdad

    dsmspickdad Proven Member

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    Leawood, Kansas
    If you deleted your A/C system, you can use the A/C switch to turn on both fans.
    #24
  25. WES_393

    WES_393 DSM Wiseman

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    Black Forest, Colorado
    Or wire the relays together. Literally takes 1 wire and 10 minutes, at least on the 2g.
    #25

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