Overheating Issue... Please Help!

Discussion in 'SN95 4.6L Mustang Tech' started by blaxican27, Aug 7, 2014.


  1. wmburns

    wmburns SN Certified Technician

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    Me personally.... I would never replace a new fan until I verified correct voltage at the fan. I would inspect the fan's electrical connections looking for evidence of overheating that could cause a weak electrical connection (a weak electrical connection could also make the voltage drop). Remember that when the cooling fan is on high it uses a lot of power (50 amp circuit).

    I would also run the fan directly from the battery to confirm it's actually running slow even when supplied with enough voltage. This would also involve testing the fan to confirm that the fan is capable of working on both speeds. Also confirm there's a speed difference between low and high speed. IMO it's a good idea to confirm that the HS and LS are wired correctly. Consider what if the new fan is wired backwards?

    Is there a back story with the "new" fan? Something why you are willing to buy another fan to replace a recently installed fan?

    My recommendation. Resist the urge to fall back into "parts changing" mode. Focus on the basics. Test. Then replace/repair.

    But if looking for some where to spend your $$, it may be better spent on a new radiator. Hard to say without looking inside.
     
    #21
    Last edited: Aug 11, 2014
  2. blaxican27

    blaxican27 Member

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    This all started with the car overheating when the a/c was only then progressively got worse. When i replaced the fan it was because my cousin (who is a mechanic) came by and told me my fans were not working. Taking his word for it he ordered a new fan for me and i replaced it. During one of my overheating, boiling over, encounters i did check to see if my fans were even turning on or not so thats when i did a little more research and replaced the CCRM. after doing that the fans now do turn on and from what i saw using my own eyes they did turn on and appeared to be spinning at normal speed.
     
    #22
  3. blaxican27

    blaxican27 Member

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    I do not know how to test voltages nor know how to run the fan direct to the battery. Those types of diagnostic procedures are out of my realm of knowledge but i am good at following directions.
     
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  4. wmburns

    wmburns SN Certified Technician

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    Do you have a Volt-Ohm meter (VOM)? A fancy unit isn't needed for basic auto repairs. But ovoid the ultra cheap units as some level of accuracy is needed.

    As for "how" to run the fan directly from battery, use two scrap pieces of heavy wire. A set of suitable size alligator clips will make attachment to the battery easier. Black fan wire to battery ground. The LS wire is RD/OG. The HS wire is OG/LB.

    Be careful not to short out the jumper during the test. Make the connections as solid as possible. Don't let the wires flail around during the test. A helping buddy is a good idea.

    You can do this.
     
    #24
    Last edited: Aug 12, 2014
  5. blaxican27

    blaxican27 Member

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    I do not have a volt-ohm meter and to be honest wouldn't know where to even start on how to use one. I have not had enough experience with testing electrical at all. Do you suggest testing the fan with the fan out or keeping the fan mounted and just unplugging the connector?
     
    #25
  6. wmburns

    wmburns SN Certified Technician

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    The force is weak on this one. Hope lost it is.<Yoda>.

    Leave the fan mounted. Then the fan is working as it does in the car with the load of the fan blades attached. It's safer and easier that way <presses easy button>

    Taking the fan out is work. If the fan blades are removed, then it's not a real load test. Testing a loose fan with blades attached is just plain dangerous.

    Perhaps some consideration should be given to using a professional.
     
    #26
    Last edited: Aug 12, 2014
  7. blaxican27

    blaxican27 Member

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    Allowing a professional is an easier yet more costly way as well. I got married two weeks ago so i am still recovering from that so any and everything i can do myself i am trying to do. I consider myself to be pretty handy with my hands and only way i will learn is by putting forth the effort and doing it.
     
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  8. blaxican27

    blaxican27 Member

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    My ground wire appears to be intact. I took my car to autozone and with the battery on the car it was reading 74%. They asked me to turn it on and told me the battery and alternator are working fine. I did check the fan once the car temp reached the middle and the fan does turn on on low but it does appear to be going slow. When I got home the car was pretty hot but not all the way on red yet and with the ac on it appeared to be spinning faster
     
    #28
  9. stangr5oh

    stangr5oh Active Member

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    I am not going to step on wmburns feet with his efforts to help you even with your limited abilities. He is doing a great job trying to guide you and I hope you can get this resolved. But, the only thing I would like to say is with you driving this car with the issues at hand just spells disaster in my opinion. I understand your need to get to work and what not. But honestly you may find yourself in a situation you can not control like a traffic jam and the car overheats and something more drastic goes wrong. Allowing a car to overheat to the point of water spewing is one thing, but to continue doing that will and can spell disaster. And that will cost way more than a few bucks if that happens.
     
    #29
  10. blaxican27

    blaxican27 Member

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    I completely agree which is why i am trying to fix this issue ASAP! Unfortunately its the only car i have and with funds limited these days i do not have too many options other than trying to either come into work earlier or and leave earlier or come in later and leave later to avoid traffic.
     
    #30
  11. wmburns

    wmburns SN Certified Technician

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    FWIIW, you do have other options. For example turn off the AC, roll down the windows and turn on the heat. Yes. The heat.

    Back in my younger days, I was driving a Buick with a stuck close T-stat. It happened when I was not in a position to fix it. I drove the car for a solid week with the AC off, windows down and heat on. As soon as the heater stopped putting out, I pulled over and let it cool down. However, often the heater trick would allow me to make the drive to work without having to stop.

    Yes it was hot that summer.

    So I can say from 1st hand experience that running the heater can and does allow a motor to be run longer than not running the heater. Without the heater being on, the motor would overheat in a matter of minutes. Completely un-driveable.

    The heater's output offered an easy way to monitor for bubbles in the coolant. Too many bubbles would cause the heater to stop putting out.

    IMO, being hot in a working car beats being stuck on the side of the road in a non-working car.

    74% battery charge doesn't sound so good to me. Should be asking why isn't it almost 100%. This could be one of the vital clues to solving the problem. Corners?

    We need to know the voltage at the battery when the fan and AC are running at idle. It doesn't have to be running hot.

    Also need to know the voltage between the alternator case and the battery negative terminal when the fan is running. This should be a low number. Too high indicates bad ground.

    What things could cause a fan to spin too slow?:
    • Bad bearings. Does the fan spin freely by hand? Does the fan run faster when supplied voltage directly from the battery? Does it start out spinning fast but slows down? If so, think about the possibility the bearings being affected by heat.
    • voltage too low. Many possible causes. Best to test with a VOM meter while fan is running.
    • Defective fan motor. Incorrect numbers of windings or other defect (cheaply made).
     
    #31
    Last edited: Aug 12, 2014
  12. stangr5oh

    stangr5oh Active Member

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    I use to do that in my 72 Gremlin X back in my know all done all days as a kid. Had a bad t-stat and could not afford one at that moment, and my father told me to run the heater while driving, ASAS it worked.
     
    #32
  13. blaxican27

    blaxican27 Member

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    As a matter of fact i am very familiar with the heater option. i have been doing that for a while now with my car over heating. i turned on the a/c last night just out of curiosity to see if the fan would spin faster, slower, or the same. My plan for today is to take my battery to get recharged or even replaced if still under warranty and to have my alternator checked as well. i am considering purchasing a VOM to do these voltage tests you are recommending i do. I replaced the fan assembly about 2-3 months ago but if need be i will consider getting a new fan.
     
    #33
  14. COramprat

    COramprat Drone Driver Mod Dude

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    Where are you located?

    Something that I haven't seen discussed. Since the car overheated is the system full? I know once they boil over you should fill from the thermostat housing or "burp" any air from the system.
     
    #34
  15. wmburns

    wmburns SN Certified Technician

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    FWIIW, the 4.6 SOHC is generally self burping (as long as the de-gas bottle is full). Assuming the cooling system holds pressure (no cracks or head gasket leaks), the air will self migrate to the de-gas bottle after a couple of heat/cool cycles.

    IF air remains after several heat/cool cycles, this is an indication the cooling system isn't air tight or has another serious issue.

    This is very different from the V6 or DOHC that can often be very difficult to get the air out of the cooling system.

    I would have also assumed that the dealer would have checked the coolant level before recommending a radiator replacement.

    A check of the basic cooling system was mentioned very early in this thread. The OP reported flushing the radiator, replacing the T-stat, cooling fan, and CCRM.

    +1 on above. IMO it's always a good idea to cover the basics before moving on. Could save a TON of work/$$'s. However in this case, if it is something as simple as low coolant level, someone has some "explaining" to do.
     
    #35
  16. stangr5oh

    stangr5oh Active Member

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    Ain't that the truth!
     
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  17. blaxican27

    blaxican27 Member

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    I am highly confident it is safe to say "low coolant level" is not the issue. I have decided to park the car and have put it up for sale for $7k with all mods and extras to go with it. In the mean time i will continue to try and diagnose the problem without investing much money into it as much as possible.
     
    #37
  18. stangr5oh

    stangr5oh Active Member

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    you are going to sale it because of this issue at hand? If that is the case, then buying a different car is going to put a larger deficit in your wallet vs just fixing this issue. Just my opinion of course.
     
    #38
  19. blaxican27

    blaxican27 Member

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    Buying a new car has been in the works but was not going to do it jut yet. In about 6-8 months i wanted to save up quite a bit then sell my car to buy me a terminator or coyote cash... I am selling the car because i have had the car for 7 years now and have had my fair of blood, sweat, and tears with it and its time to move on to something different. With the money i get from the car i will buy me a daily and continue to save to purchase my next mustang.
     
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