Car overheated on highway just now, I'm still out here...

Discussion in 'Boss 302 and S197 Technical Forum' started by gripdriver, Aug 28, 2018.

  1. gripdriver

    gripdriver TMO Race

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    On the way to work this morning on the 202 just past dobson rd in chandler AZ and my coolant temp started climbing, and my warning light came on.

    I shut it off, and parked it on the side of the highway.

    Ive never had cooling issues, infact because i live in AZ i focused on engine cooling for a little while.

    14 GT TP, with GT500 fan/shroud, boss 302S grill, boss 302 intake manifold, long tubes, hood vents.

    Car has 44k miles, factory coolant, factory thermostat.

    My first guess is thermostat failure. I opened the hood and had a slight slight hint of a coolant smell. But the engine wasn't radiating heat like i was expecting. I can lay my hand on the intake manifold and its not very hot.

    Any ideas on what this could be.
     
  2. Mad302

    Mad302 TMO Race

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    Is the fan still running?
     
  3. gripdriver

    gripdriver TMO Race

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    No it is not. I moved relays around, i checked fuses. The fan does not come on.

    The GT 500 fan and shroud is less than 10k miles old.
     
  4. gripdriver

    gripdriver TMO Race

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    I limped it to work, I had to stop and let it sit in the shade for 20 minutes to cool off as the coolant temp hit 232F at one point.

    The fan does not come on, and I used the heat in the cabin on MAX to help limp the car along.

    Once it cools off to the point I can stick my hands in there, I will be testing the fan.

    Anyone have any other idea's?
     
  5. byronj

    byronj TMO Addict

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    My Boss had a cooling issue. Came down to the coolant reservoir cap had a bad seal. Good luck in solving the problem
     
  6. ArizonaBOSS

    ArizonaBOSS Because racecar. Moderator

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    Wow that sounds terrible. Is there anything blocking your AC condenser or radiator? Check fan and radiator cap as suggested. Any chance it is a bad CHT sensor? See if any broken wires on back side of passenger bank cylinder head.
     
  7. gripdriver

    gripdriver TMO Race

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    checked the coolant res cap multiple times, its holding pressure. I may buy a new one anyways since they bare cheap.
     
  8. gripdriver

    gripdriver TMO Race

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    radiator, and ac condenser are free of obstruction and damage. the fan never comes on. im going to go out and pull the cooling fan resistor now.

    replacement P/N DR3Z-8L603-A for the 13-14 GT500 cooling fan. $25 at tasca
     
  9. gripdriver

    gripdriver TMO Race

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    FML, its on national backorder for about 2 more weeks...gonna go pull the one in the car and see if that's it.

    I will check the CHT sensor as well while I am out there.

    Thank you
     
  10. WinterSucks

    WinterSucks TMO Addict

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    No expert, just thinking out loud. If the fan is not coming on and you got the impression that it was no hotter than normal when you had the hood open then maybe it is not actually overheating and like mentioned it might be a faulty CHT. The fan might only be triggered by the coolant temp which would be low if you keep you speed up. If you just watch the temp closely and let it idle then the fan should definitely come on.
     
  11. gripdriver

    gripdriver TMO Race

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    Pulled the cooling fan resistor, it is burnt up and smells of electrical fire. The plug on the chassis harness side is also charred.

    I scuffed up all the contacts, cleaned it all with contact cleaner, and plugged it back in....he fan worked again.

    Ill test it again before I go home today, and hopefully it will work long enough to get me home where I can park the car for a few weeks until I can buy a few new cooling fan resistors.

    I am scared of an electrical fire and overheating....
     
  12. gripdriver

    gripdriver TMO Race

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    ordered 2x P/N DR3Z-8L603-A, and 1x P/N DU2Z-14S411-ABA to get everything squared away. I will still do research on this to figure out how this happened, and see if I can come up with a fix to this issue.

    As I said before the resistors are on national backorder, so hopefully Tasca accepts my order and ships them when available. If not ill have to call them next week to see if they have them (ETA supposed to be Thurs 9/6)
     
  13. gripdriver

    gripdriver TMO Race

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    This is frustrating, I have no idea why this resistor has burned up. The 40A fuse, and the high and low speed fan relay's are both fine.

    literally everything looks fine except where the cooling fan resistor plugs into the factory harness. All of the spade connectors are charred.

    what would cause this?
     
  14. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    Pics might help others find your problem, but you're right to be concerned about anything 'charred' or 'burnt up'.
     
  15. JAJ

    JAJ TMO Race

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    The crimp that holds the wire in the connector was either loose or corroded. A bad connection creates heat when current is flowing, and it just keeps getting worse until the connector fries and the circuit is open.
     
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  16. gripdriver

    gripdriver TMO Race

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    This is the conclusion I have come to as of this morning. Everything was brand new, and sealed from the elements (dust and sun in Arizona). I think heat and vibration caused a loose connection on the female spade contact which caused arc'ing and eventually an open.

    I am planning to experiment with the burnt up resistor and harness to come up with a bullet proof setup. Most likely swapping from 12AWG wire to 10AWG, as well as keyed, environmentally sealed, and vibration proof amphenol MIL spec connectors with a locking ring and gold plated male/female contacts.

    If this ends up working on the current resistor/harness, I will build 2 more like this.
     
  17. racer47

    racer47 All I got left is fast

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    Grant 302 and ArizonaBOSS like this.
  18. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    [​IMG]
    [​IMG]

    Well, that would meet my definition of charred and burnt up.

    Certainly looks like a problem with arcing in this example. Just not sure if it's between the two female connectors.
     
  19. gripdriver

    gripdriver TMO Race

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    That's how mine looked. the most charred connector is the ground connector.

    top left contact in top picture.
    bottom left contact in bottom picture.

    I also think the issue is the Amperage draw Vs. what the 12awg cable ford used is rated for.

    the GT500 Fan pulls 24.5Amps continuous, with a 30+ amp spike when the fan starts up. I do not think the cheap quality copper 12awg wire plus the cheap contacts are made to handle that amperage.

    what I cannot explain is why this does not seem to be a common problem on 13-14 GT500's from the factory, or 13-14 GT's that upgrade to the GT500 fan/shroud/resistor?

    I have started gathering parts to build my bomb proof resistor/harness. 10Awg superflex nickel coated copper cable that can handle 90amps from -60C to 200C.

    I hope this idea works...
     
    Last edited: Aug 29, 2018
  20. gripdriver

    gripdriver TMO Race

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    Thank you, I have seen that link, and have ordered that pigtail from tasco as a part to keep in the garage. I have also read as many threads as I could find on SVTperformance.com, s197forums.com, and trackmustangsonline.com

    It seems this problem has existed for a while in the SN95 cars, and still exists in the S197 cars. Some people have luck just replacing the fan resistor, some have luck adding dielectric grease, some have luck doing a combination of dielectric grease, wire brushing contacts, squeezing contacts to mate tighter etc. etc.

    But I have yet to find out why this happens in the first place. I have noticed that people keep bringing up "tunes" meaning that the Tuner throws a tune on an sctx4 or whatever, and sets the fans to trigger on at a lower temp, and run longer until it gets the coolant to its set off point. I have a lund tune, and an sctx4...I wonder if I can see or possible change my on off points for the fan?

    does anyone know the factory 13-14 GT cooling fan on and off settings? what about the 13-14 GT500 on and off settings?
     

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