Electric Fan Temp Sensor Location Debate

Discussion in 'Fox 5.0 Mustang Tech' started by Grabbin' Asphalt, Jun 12, 2013.

  1. Speaking of the radiator sensor placement only.....

    I've read where many have said:

    1) place it near the radiator exit.
    2) place it near the radiator inlet.
    3) placement anywhere as long as the temp sensor/thermostat are in conjunction.

    What do you think???
  2. Are you talking for a fan switch with temp. sensor? If so, I would want it in the top of the motor.
  3. The capillary tube that slides into the radiator
  4. if it is the radiator temp probe, you want to place it near the upper radiator hose, about 2 inches or so below the hose.
  5. What he said, but read the instructions too.
  6. And when you read those instructions, they'll tell you to put it near the upper rad hose.
  7. So I've read where others place it near the exit, instead of the inlet, because when the coolant comes into the radiator it will always cut the fan on because it hasn't had a chance too cool. Stating if the temp is high it will be on while cruising. When it shouldn't come on at all because of the passing air.

  8. So basically saying, thermostat control the upper and temp sensor control the bottom and it will continue to cool if you need it.

    What do you think??
  9. The directions state that you should put it near the upper hose, I believe in my car I am going to tap the Thermostat Housing and install it there.
  10. Yes I've seen the directions saying that, ...that's exactly why I could understand the people saying on there's, it never cuts off once the engine got to operating temp. And if they turned the temp setting any higher it would jeopardize when they came into traffic situations.
  11. Alternate placement for a temp gauge sender:

    Revised 24 July 2011 to add better temp sender location description and the necessity to loop the fluid flow through the heater circuit.

    How it works:
    If you want any kind of operation similar to stock, the ECT/heater feed line is the best place for a temp sender or fan thermo sensor. After all, the computer uses the ECT to pick up data on how warm the engine is. Putting the temp sender in the same line as the ECT is a simple way to get the best possible accuracy at minimum cost and complication.

    Some things to keep in mind:
    Just be sure that you haven’t blocked the coolant return because of a leaky heater core. For this to work correctly, the coolant needs to flow from the ECT sensor tubing back to the water pump. That means a leaky heater circuit gets looped rather than just plugged up. Join the rubber hoses together with a hose splice from Home Depot rather than plug them up.

    Where to put it:
    Use the heater feed that comes off the intake manifold that has the ECT sensor in it. Cut the rubber hose that connects the manifold water feed to the heater and splice in a tee adapter for the temp gauge sender. That way you will get the most accurate temp readings since the coolant is always flowing through the heater circuit in a stock car.

    Tee adapter info:
    Make a pilgrimage to your local hardware or home supply center and get some copper pipe and a tee that fits the temp gauge sender. Solder two pieces of copper pipe onto a copper pipe tee with threads in the tee part. Find the correct brass fitting to match the temp sender threads to the tee fitting.

  12. I do like that idea Nice!!! :flag:
  13. The only people who say the fan never turns off are the people who haven't bothered to properly adjust the controller. The temp probe doesn't give a rat's ass if you're tooling down the highway or sitting in traffic with the A/C on in 110 degree weather, it only knows what the water temp is coming out of the engine. If it's hot, the controller turnns the fan on. If it's getting hotter, it turns the fans up. Don't overthink it.
  14. Thinking about the operation of electrical fan is a concern because of the cycling it does. Electronics only last for so long for anything, so with the cost/reliability of an electric fan it should require some planning for sure, longevity is the key. I believe there maybe a limit to what would be beneficial for say a 180 v.s. 195 stat. Because the coolant coming out of the engine will always be hot regardless, no way it won't be hot. But HOW hot is the factor with how fast it's traveling through the engine ie: stat degree.

    I believe the 2 parts coupled with that thought is the (temp of the radiator fluid) waiting to be entered and the (temp of the fluid in the engine) already being used. So if the radiator does a super job of cooling the fluid on it's on (driving down the highway) then it will not need the fan and the temp of the engine will be relied strictly on the stat-temp.
    The fluid coming out of the engine will be hot regardless :hug:

    But yes this is very thought provoking :scratch: cooling_diagram.jpg
  15. That's stellar! Those clowns that design, manufacture, and write instructions for fan controllers, all day and every day, clearly haven't thought it all through, like you have. Bravo, my friend. Bravo.
  16. Woe.....

    We're just discussing and considering possibilities that are relevant to electric cycles. So if we're going by "thought it through instructions", ....then loctite for every bolt thread then....lol
  17. The engine temperature varies a ton based on where you measure. Sure the temp will be different if you measure at the rad inlet vs. outlet, but by the same token the temp within the cylinders will be 100x higher than either place, so which temp is most important to pay attention too?

    Easy answer - use the same location as the industry standard - top of manifold, or as JR suggested T into the bypass - basically the same - in both cases your temp control is consistent with the thermostat operation & dash temp gauge reading.

    If you put it somewhere else, you're opening yourself up to unnecessary problems such as: "Why doesn't the fan come on even though the gauge says I'm overheating?" or "Why is my fan running full blast even thought the thermostat isn't open?"
  18. I think you are overthinking it.
  19. Guys I'm just provoking thought here cause I think it's something to consider all the avenues and possibilities, so bear with me. Not arguing by any means, we're just discussing and yes maybe over thinking it to a point but non the less, thought provoking.

    Yes, knowing the true "actual engine temp" is critical and is very much appreciated there, so I really do like that idea of the temp install in the bypass by JR.
    While having the temp control consistent with the thermostat was answer "c".
    With the 2 scenarios, - The fan however, will not come on when the thermostat is closed in either location, up high at the the inlet cause "no coolant is coming in" to signal it's hot to the sensor or the same down low at the exit. That scenario is either 2 reasons for the stat not coming open, (1) coolant is not up to engine temp and the other coolant inside the radiator is still/already cold or (2) stat is stuck closed.
    Having the fan come on when the temp gauge reading overheating is separate, meaning that should be "in conjunction" already with the true "actual temp gauge" already, whether stock or aftermarket gauge.
    One can turn the dial temp on the fan to come on with any normal "the usual stock reading" for that particular car.

    I believe the best way to run this set up is to install a "actual engine temp sensor" in the bypass as stated above (or use normal/usual stock reading in conjunction until a gauge can be installed) and place the electric radiator sensor halfway up driver side. That would allow a little time for the coolant to be cooled by the radiator while cruising and would save the cycling life span of the fan ultimately. Then in traffic it would be minimal delay before the fan would cut on once stopped.
    When it cuts on once, the "in traffic" temp cycle has begun.

    Yes way over thinking this, but hey that's what gearheads do :rlaugh:
  20. Neat idea, never heard of doing it. I just use a spare intake manifold fitting to accomplish the same think when using an aux. gauge. Do the probes that fit between the fins have any threaded fitting like this? Ones I have seen were more like a gas water heater/Gas furnace thermocouple.