Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Thermostatic Electric Fan Switch

Discussion in 'The Garage' started by mr.smartass, Apr 11, 2005.

  1. mr.smartass

    mr.smartass 1 ton status Premium Member

    Joined:
    Aug 10, 2004
    Posts:
    10,860
    Likes Received:
    4
    Location:
    Hattiesburg, MS
    I need one... i ordered my new 4 row radiator and it has a special outlet for a sensor or switch, i want to put a switch there for my two 14" fans, i have my wiring all layed out i just need a switch that will turn my fans on and off at the temp i want(like on at 195 and off at 175 something like that), i want the switch to be preset so a stock switch from a vehicle would work fine, the hole is 1/8 pipe thread if i'm not mistaken but it can be adapted up or down a little without affecting the reading to much. any part numbers or anything would be helpful. it needs to be a thread-in switch.
     
  2. mikey_d05

    mikey_d05 1 ton status GMOTM Winner

    Joined:
    Nov 23, 2004
    Posts:
    10,453
    Likes Received:
    0
    Location:
    Minnesota
  3. mikey_d05

    mikey_d05 1 ton status GMOTM Winner

    Joined:
    Nov 23, 2004
    Posts:
    10,453
    Likes Received:
    0
    Location:
    Minnesota
  4. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    For GM applications, a later Grand National (try 1987) supposedly has the lowest "common" fan switch on temp.

    I think you'll find it hard to find a (factory) fan temp switch that is much lower than whatever they used on that car, trend is/was to let engine temp get relatively high before the fans come on.

    Primary fan in my setup (1987-88 TPI) is set by GM (ECM control) to come on at 220* I believe the off temp is 200 or 210*, and the secondary fan switch (ECM independent, its an actual switch) is set to come on at 240*.

    If you have a Napa near you though, their Echlin catalog has a very good switch section and selection...each switch is described by temp on/off, thread pitch, and wiring.
     
  5. mr.smartass

    mr.smartass 1 ton status Premium Member

    Joined:
    Aug 10, 2004
    Posts:
    10,860
    Likes Received:
    4
    Location:
    Hattiesburg, MS
    thanks fellas, yeah i have a relay that actually looks like a start solenoid but it's setup for continous voltage, i think it'll work, yeah all i really need is the switch, i have couple of hayden kits in stock at my store but they just don't look heavy duty enough for my application, i also have an adapter that goes from 3/8" to 1/8" if it comes down to it, i guess i'll head down to the local napa and check out the Echlin catalog and see what they have available.
     
  6. mr.smartass

    mr.smartass 1 ton status Premium Member

    Joined:
    Aug 10, 2004
    Posts:
    10,860
    Likes Received:
    4
    Location:
    Hattiesburg, MS
    Napa was no help on the subject... i called over there while i was at work and tried to get the guy to look me up one, he said the only ones he could ever find in his Echlin catalog were either to high in temp, or metric thread... i saw one that i liked on the jegs website but it was like $32 trying to avoid that... I'm wondering, maybe I should just go higher on my temp. what's a safe temp. range for our trucks? Like i said i'll have a nice new 4 row radiator that should keep it down some.
     
  7. Blue85

    Blue85 Troll Premium Member

    Joined:
    Jul 26, 2000
    Posts:
    9,092
    Likes Received:
    492
    Location:
    Grand Rapids area
    How about this?
    Summit switch
    I don't know what the thread pitch is.
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    Bah, I made the guy at the counter let me look at theirs, so did my dad for his race car. It has foreign and domestic, guy must have been lazy, not incredibly tough to blow you off on the phone. I wouldn't ask them to look some up though, there were easily 5 pages of them when I was looking.

    Since the GN switch is "known" to be a "colder" switch, I'd focus on that. Off of the gnttype website "The second (thermostatically controlled) fan turns on at 203x F and is not under ECM control."

    That is MUCH cooler than the Camaro one at 240*. That might even be too cold if your engine typically runs in the 195* range. You don't really want the fan on all the time if you can help it.

    If you can get a fan on temp around 220*, you should be good. GM doesn't see that as a problem on small blocks, neither do I.

    You could always go to a wrecking yard and just grab a bunch of them from GM cars. Later (depending on engines) on there are metric threads, but that typically is on the engines that were designed from the ground up at a later time, not like a 3.8L or 2.8L. FWD cars seem to be the best donors, just easy access and a lot of them out there.

    I would *suspect* the earlier the application the lower the fan temp. Problem with the GM stuff (if its a problem lol) is that they used the same sensors in so many vehicles, you may end up with 10 of the same switch. Some I've seen have the degree stamped into the body of the switch, so that may be something to check too. Thats if you like going to the wrecking yard. :)
     

Share This Page