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Projects Fan Controller

Discussion in 'The Hokey Ass Message Board' started by AldeanFan, Jun 14, 2020.

  1. AldeanFan
    Joined: Dec 12, 2014
    Posts: 549

    AldeanFan

    I know I know, electric fans are not traditional I suck and should put a mechanical fan on with a shroud.
    Now that that’s out of the way.

    I have an electric fan on my Country Squire, mounted to a shroud that covers the whole rad and spaces the fan about 1” from the rad.

    The fan is controlled by this adjustable controller:
    https://www.summitracing.com/parts/hda-3647
    The radiator probe is in the top corner of the rad.
    They don’t publish the temperature range between on and off like some others do.

    My complaint is that the fan cycles constantly while idling. It sometimes turns on for less than 10 seconds and shuts off, other times it will shut off and come back on before the fan has even stopped spinning.

    The car doesn’t overheat or push coolant, it just annoys me that the fan is constantly on/off/on

    I have a similar electric fan and shroud in another car but with this switch:
    https://www.summitracing.com/parts/der-16730
    And it doesn’t short-cycle the way my wagon does, it comes on, runs till the car is cooled down and then shuts off for a while.

    I’m thinking I’ll try a screw in fan switch and see if that does anything different.
    Any other suggestions?


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  2. Almostdone
    Joined: Dec 19, 2019
    Posts: 245

    Almostdone
    Member

    Two suggestions: 1) move the temp sender to the intake manifold, 2) try an adjustable fan controller (I looked at the one you posted, but can’t tell if and how it gets adjusted).

    The coolant temp will often be higher in the intake than in the radiator (especially in the bottom of the radiator, but you said yours was in the top), and you want to get an accurate reading from the system.

    The controller in the photo is what I have and seems to work well. I say ‘seems’ because I’m not done with the car and thus far it has only been run in the garage. That being said, it is easy to adjust to trigger at a temperature you want and taps into the water temp gauge for the temp signal, which I find very handy. I got mine from Centech, which is where I got my wiring harness. You can probably get something similar elsewhere. The folks at Centech were very helpful. I think it was about $80?

    john


    6BF82FBD-0C8F-4646-8D50-AC231260C691.jpeg
     
  3. The fan switch that reads coolant temp in the head works good. The one you showed is a pretty low temp range.

    I run 180 degree stat. Fan goes on at 210, off at 195. Engine runs about 195 unless stopped for a couple minutes. When fan comes on, temp begins to drop immediately.

    Phil
     
  4. KenC
    Joined: Sep 14, 2006
    Posts: 404

    KenC
    Member

    I suspect the sensor in in the airflow and is more effected by the air temp than the rad temp. Can you move it to a location out of of the airflow? Or, place some sort of block to prevent incoming air from flowing over that area? A small area near the upper hose connection and outside the shroud would be best. Cheap and easy to try a move first, before buying parts.
     
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  5. The Shift Wizard
    Joined: Jan 10, 2017
    Posts: 1,954

    The Shift Wizard
    ALLIANCE MEMBER

    Try blocking off a square inch or so of the radiator fins directly in front of the probe. The probe itself is rather long and could be positioned in the cooler air at the radiator's front side, especially if the radiator is a thinner version. You can also try sliding the probe out, less deep. Try some free stuff first to see if anything changes.
    A good controller should have a little electronic delay built-in and 'average' the temp over a short time span but not act like an instant on/off switch.

    Edit: Ha! KenC beat me to it while I was still thinking about what to say. :rolleyes:
     
  6. AldeanFan
    Joined: Dec 12, 2014
    Posts: 549

    AldeanFan

    Thanks, I like that fan controller but I don’t have an electric temperature sensor,

    The controller I’ve got now has a temperature probe so I’d have to change the controller to put it in the intake manifold.
    There a little slot to put a small screwdriver in to adjust the temperature that the fan comes on, but no markings so you just have to guess at what temperature you’re setting it at.


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  7. AldeanFan
    Joined: Dec 12, 2014
    Posts: 549

    AldeanFan

    Thanks, this is probably what I’ll go with as it works for my other car.


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  8. AldeanFan
    Joined: Dec 12, 2014
    Posts: 549

    AldeanFan

    Great idea,
    I made the shroud to cover 100% of the rad so there is nowhere that is not in the airflow, but a square of duct tape over the sensor should stop air flow enough.


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  9. AldeanFan
    Joined: Dec 12, 2014
    Posts: 549

    AldeanFan

    At least I’m getting a consensus!


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  10. AldeanFan
    Joined: Dec 12, 2014
    Posts: 549

    AldeanFan

    Well it’s midnight but I’ve proved that the radiator probe in the air flow from the fan was causing the short cycling.
    Some duct tape over the prob area totally stopped the short cycling.

    The engine is running at 180 with the fan running constantly, radiator temp is 165 so it’s certainly cooling,
    However the the fan runs constantly at idle.
    Not sure If it’s not enough rad or not enough fan.

    A higher flow fan is cheaper than a bigger rad so I’ll likely try that first.


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  11. The Shift Wizard
    Joined: Jan 10, 2017
    Posts: 1,954

    The Shift Wizard
    ALLIANCE MEMBER

    Actually, the fan running at idle is not a bad thing. At highway speeds, the fan is just going along for the ride and you get plenty of airflow from the high-pressure air stacking up in front of the radiator. At idle and slow speeds there's none of that and the fan has to do all the work.
    I had one occasion where I forgot to plug my electric fan back into the harness (O/T daily driver) and I went on a 150 mile trip on a 90-degree day with no overheating until I got to my destination and had to wait in line to check-in. It took less than a minute to overheat. I literally had to shut the engine off over and over just to roll up one car space at a time.
     
    Last edited: Jun 16, 2020
  12. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 2,344

    2OLD2FAST
    Member
    from illinois

    An engine runs "dirty" ( rich) at temps below around 195°-200° , adjust it so it comes on at 205°210° ,running at idle is fine. But keep the temps up ....IMO
     
  13. AldeanFan
    Joined: Dec 12, 2014
    Posts: 549

    AldeanFan

    Thanks for the advice,
    I’ll keep adjusting the fan controller till I get it how I want it.

    Unfortunately the fan controller doesn’t have any graduations or markings, just a slot to turn with a tiny screwdriver to adjust the temp that the fan comes on.

    Now that it is not cooling the probe off I’ll need to adjust it higher.

    It’s similar to a problem I had with the hanging furnace in my garage, when I first installed it the furnace was blowing towards the thermostat and it would short cycle, next I tried putting the thermostat below the furnace and it never got air flow so the furnace wouldn’t shut off. Finally I found the right spot.




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