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3 temp sensors on stock '94 7.3 turbo

Discussion in '6.9L IH & 7.3L IDI Diesels' started by Noiseydiesel, May 25, 2019.

  1. Noiseydiesel

    Noiseydiesel Registered User

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    Okay. Here i am spending money to get maintenance things taken care of.
    One sensor is close to the filter and has two blades on it. That got changed. The other one is close to the exhaust manifold on the drivers side and that runs the temp gauge on the dash, correct?
    That should leave the one in the middle that is the overheat sensor?? Where can I find a replacement?
    Thank you in advance!
    Bruce
     
  2. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    The one with two spades is a temp switch for the cold advance and high idle. The one near the exhaust manifold on the head is the overtemp switch, the one near the timing gear cover is for the coolant temp gauge 51095154-FF58-4F60-BFA5-8296417371C4.jpeg
     
  3. franklin2

    franklin2 Full Access Member

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    Best thing to do is pull the overtemp switch out, tape the wire off, and put a aftermarket gauge in it's place. That way your original temp gauge will work, and your aftermarket gauge will tell you the real temp of the engine. Who needs the temp gauge to peg and the check engine light to come on? That's all the over temp switch did.
     
  4. Noiseydiesel

    Noiseydiesel Registered User

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    Boy! Was I a bit off course. I thought the over temp sensor was the one for the gauge. Guess I will be adding an electrical temp gauge for the engine and add another into a trans line at least.
    Now to find a pillar post gauge set bracket.
    She already signed off on spending the money. . . . so far.
     
  5. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    I did mine a little bit differently. I've seen others on here say that the best place for the probe on a mechanical gauge is where the factory put the sender. That makes sense to me so I put my probe there. Since I hate non working gauges, and I also know that the factory gauge isn't very accurate, I soldered a few inches of wire into the temp sender wire to lengthen it some and then put the sender in the plug in the top of my water pump. It doesn't seem to read much differently than before. For whatever that's worth.
     
  6. Golden Helmet

    Golden Helmet Full Access Member

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    There's a plug on the rear of the driver side head that you can remove and put a temp sender in, then both your factory gauge and overtemp switch are left intact. That's how mine is set up.
     
  7. franklin2

    franklin2 Full Access Member

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    I believe I read somewhere that you will get different temps readings at all those different locations. The main thing is to have a baseline after you move it and add another, and then monitor that for any dramatic changes.

    The main reason I used the temp switch location is at the time I was in a hurry, and the gauge I bought only had one adapter bushing and that is the only spot it would fit in without running to the store to buy another.

    And like I said, I think the theory behind the temp switch is a little bogus, just like the oil pressure switch hooked to the oil pressure gauge instead of a oil pressure sending unit. Apparently Ford though their truck owners were too stupid to be able to read a gauge and determine the operating conditions of their engines.
     
  8. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    Unfortunately, most people are. Maybe not most (or all) of us on here, but the general public. So I guess that was good thinking on their part.
     
  9. Selahdoor

    Selahdoor Full Access Member

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    I'm afraid it is a bit more banal than that.

    They saved money.

    If all they saved was a dollar a vehicle, they saved millions. And they obviously saved several dollars per vehicle.

    They saved 50 cents per vehicle by putting the Pinto onto the roads as a fire bomb waiting to happen. They knew it was going to happen. They knew people were going to die. But their actuaries told them how many people were likely to die and how much they would probably end up having to pay, for the deaths. Their bean counters told them how much they would save by letting people die, rather than fix the problem.

    This is not made up. There was a major lawsuit over it, and it was all made public.
     
  10. snicklas

    snicklas 6.0 and Loving It!! Staff Member

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    I believe (I think I actually read it in an article) the reason Ford went with the oil pressure switch starting in 1987 (and it't still this way, my 03 6.0 and 11 3.7 is the same way) was customer complaints. With a sending unit and the gauge moving around, or the "I drove my buddy Bob's truck and his oil pressure was higher on the gauge on mine is, so there has to be something wrong that you need to fix" returns. If every vehicle has the needle in about the center of the gauge, they get less complaints. Remember, having a gauge for anything other than fuel or temperature was the norm. Even into the 70's and early 80's, a battery light and oil pressure light was common. I remember seeing the 73-79 Dentside Pickups and Vans, have a gas gauge, a temperature gauge, and a batt (or alt) light and and OIL light. They had to be ordered with a full set of gauge. 80 was the first year that all 4 gauges were standard. I don't think I have seen a bullnose with just lights, I think they all fad gauges. Think of how many complaints they received in 6 years. Plus, with with them still having the IVR, and the gauges having a mind of their own anyway, I can see why they went to a switch causing the needle to move to the middle. Most of the general public will enjoy the warm fuzzy of a gauge that doesn't move. Then even have moved away from have in all the gauges. My 2000 P71 had al 4, my 2007 P71 only had 2, everything else was a light. I think the trucks having gauges is mainly "trucks should have gauges". My 11 F-150 3.7 V-6 has" Oil Pressure, Coolant Temp, Fuel and Transmission Temp gauges. They are still the classic, no numbers, just a range that Ford normally does. But the oil pressure gauge comes up to just to the high side of center and never moves. The other 3 move. The oil pressure gauge is just a "light with a needle" Even on my 03 6.0 it even says int he manual when the oil pressure is above 7 PSI the needle will move to the center of the gauge.
     
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  11. franklin2

    franklin2 Full Access Member

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    You are correct, they are moving closer and closer to just one light on the dash that says "Bring your truck to the dealer for service" no matter what the problem is, so we can charge you so much money you think about buying a new truck. They are trying to drive out do-it-yourselfers and small shops and small fleet services and make them all go to the dealer. Luckily we still have smart people that make aftermarket scanners and programming, and they can't stop the junkyards from selling parts (yet).
     
  12. ifrythings

    ifrythings Full Access Member

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    Here’s how to solve the “where to put the temperature probe” problem.

    92BC481B-02BD-42E9-B83D-63CCD665EF75.jpeg BF38FEC6-99ED-4CD0-A379-74EBC20769E7.jpeg
     
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  13. franklin2

    franklin2 Full Access Member

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    Go easy on that teflon tape on the single wire sensor. I am sure you know that sensor need good ground to work, good habits of putting lots of sealer on threaded fittings are hard to break when dealing with these sensors that need a good connection to the engine block.
     

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