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7.3 IDI w/ banks turbo overheating

Discussion in '6.9L IH & 7.3L IDI Diesels' started by Cole Roberts, Jun 4, 2020.

  1. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    I don't think that would have anything to do with it. There's still two belts that are running your water pump and that turns your fan.
     
  2. Shadetreemechanic

    Shadetreemechanic Full Access Member

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    If you are still having the same issue after two fan clutches, odds are its a different issue. That radiator looks original. How do the fins look on the inside and out? It may be time for a good rod job or replacement.
    If your radiator is clogged up and not dumping the heat out of the radiator, the fan clutch will not engage.
     
  3. franklin2

    franklin2 Full Access Member

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    It is a well known fact that the factory style clutches are "late" to come on. The question I have, how are you measuring temperature? The factory had two different spots with a sensor and then a switch. Those different spots, and then other spots you can install a sensor give very different temp readings. And I would not rely on the factory guage for any good information.

    When you hit 240 you should be able to smell a oil burning smell on the engine. Do you have any other signs that it's overheating?

    And if all you do is tow with this truck, I would consider locking the fan like I did. If you do a lot of unloaded highway high speed trips, I wouldn't lock the fan. But if you just drive locally, and are always towing or hauling, it will be one less thing to go bad and break, and you always have max cooling when you need it.
     
  4. aggiediesel01

    aggiediesel01 Full Access Member

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    Take your old clutch and either add fluid as discussed earlier or lock it, whichever is easier for you. Put it back on and see if you can hear it now. If it makes a difference in your temps then you know you got another bad one. If not you can put money into a radiator or thermostat instead.
     
  5. vegas39

    vegas39 Full Access Member

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    Im gonna give my two cents, as I have the same issues with the 93 in my sig. Ive done everything under the sun to my 93 including trying 3 different radiators. My truck runs hot in the desert down here, so hot that I cant even pull our 32 foot travel trailer with it. The last trip we took, I hit 250 on the grade to searchlight nv.
    My fan clutch comes on later like many of the new ones, so the last trip we took, I reached down and popped the spring out of its slot so it would be locked full time. Even with the fan roaring constantly, the temps still climb right up.
    We have owned one 6.9 and three 7.3 trucks and the only one that ever ran cool, was the 6.9. We know that the 6.9 head has more cooling passages and in this heat, it makes all the difference in the world. Ive had my fuel settings all over the place and same with the timing and nothing makes this truck run cool.
    Im to the point now, that I told my son as soon as he gets his permit, he can have my 93. Ill be looking to buy a new gasser. ugh! Not that I want too but this thing cannot tow, period.
    Also, for anyone wanting to use Champion radiators, Ive had a 4 row, a 3 row and am currently running a large tube two row from "O" however you spell it. I find that the current one seems to have a slight edge over the champions.
    If anyone has a hidden miracle for us to make these things run cooler, Id be glad to hear it.
     
    mandokyramud likes this.
  6. Cubey

    Cubey Full timer RVer

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    Last year, my RV's original fan clutch was weak but still working fairly well. It only came to my attention when I was hitting very strong head and cross winds in SD and my factory temp gauge was climbing high when trying to maintain 45-50mph. Never overheated it thankfully since I was on a back highway where I could slow down as needed. @IDIBRONCO helped me replace the fan clutch a few months later when I was passing through. We did the thermostat too since the alternator and upper rad hose had to be removed to do the fan clutch.

    I went with a "closeout" Motorcraft fan clutch from RockAuto for about $60, give or take. I put an Equus mechanical temp gauge before the fan clutch and thermostat were replaced, so I saw what temps it was going. Typcical range at highway speeds was 190-210 with the old one. With the new one, it's about 180-195. The thermostat was likely the original too, so it was beyond time to replace it. I kept the old fan clutch and thermostat as emergency spares because why not?
     
  7. franklin2

    franklin2 Full Access Member

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    These engines were used in dump trucks, school buses, u haul trucks, etc. Of course any engine will overheat in the right conditions, but there is something going wrong with your setup, you just haven't found it yet. I do know even with my locked fan, if I am pulling a mountain with a loaded trailer, I can overheat mine also. These engines have lots of torque down low, and will keep on pulling at a lower rpm. But if I pull the mountain like that, the temperatures will start to climb. I have to force myself to downshift and let it scream, and then with my locked fan I can watch the temps start coming down, while still making slow progress up the mountain.

    If you have a automatic, you might have to pull the lever down and force it to downshift. The waterpump turns faster, the fan pulls more air through the radiator, and there is more air going through the engine, especially if you have a turbo.
     
  8. Garbage_Mechan

    Garbage_Mechan Garbage Mechanic

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    Vegas39 your problem is deeper than most and likely a small combustion leak into the cooling system.

    To the OP: In cases like yours where even a new fan clutch doesn’t come on either the hot water is not getting to the radiator or the hot air is not getting to the front of the fan clutch. If the thermostat and the bottom radiator hose sucking flat have been eliminated then here are a couple I have run into.
    If the radiator core is externally plugged with dirt and bugs limiting air flow, the hot air will never reach the thermostatic spring.
    If the tubes in the radiator core are internally plugged in the area of the fan clutch, hot air will not reach the thermostatic spring on the clutch.
     
  9. Garbage_Mechan

    Garbage_Mechan Garbage Mechanic

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    On the external I can’t count how many times I have had mechanics tell me a cooling stack was clean when it really wasn’t. If you can’t see light through every square inch it isn’t clean. Sometimes had to pull the radiator, blow out all dry debris before getting it wet and swelling it, then soaking with AC coil cleaner and the washing.Sometimes miraculous results.
     
  10. Garbage_Mechan

    Garbage_Mechan Garbage Mechanic

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    On the internal drain the coolant down below the top of the tubes and look in through radiator cap at the tube ends. Solder bloom ( white corrosion) and calcium build up are easy to see but tubes can still be plugged internally too...
     
  11. franklin2

    franklin2 Full Access Member

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    Radiator guy showed me a trick to check for a clogged radiator. He said drain the radiator and take the lower hose off. Hold the palm of your hand over the lower radiator outlet to plug it off, and fill the radiator to the top with water. Then quickly pull your hand off the lower outlet. He said the lower outlet should flow full volume smoothly till the radiator is empty. If it gulps and gurgles and is not full volume as it's draining, then the radiator is partially clogged.
     
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  12. 79jasper

    79jasper Chickenhawk

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    That is interesting. And I see the way it works.
    Wonder if it would be the same for a horizontal tube radiator...

    Sent from my SM-N960U using Tapatalk
     
  13. vegas39

    vegas39 Full Access Member

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    Ive never had to add coolant to my truck. I would think with a combustion issue, id be losing it. My sons truck runs hot also but not as bad as mine. His truck is N/A.
     
  14. vegas39

    vegas39 Full Access Member

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    I drove those old school buses when they were new and even a few of the old 26 foot uhauls. Those things all had bigger radiators and no turbo. I could turn my fuel down even more but then the truck becomes a gutless pig in 105 plus degree weather.
    I get that but where you live, it doesnt get 115 degrees. Its crazy how much hotter a vehicle runs just from going 100 degrees outside to 115 plus. I drove those old school buses and a few of the old 26 foot uhauls. The advantage they had, were bigger radiators and they were N/A. It really is frustrating to drive.
     
  15. vegas39

    vegas39 Full Access Member

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    To the OP. Sorry, dont want to look like a thread stealer. Was just trying to say that by the end of the day, these 7.3's run pretty warm in the right conditions, especially if you have a turbo with the fuel turned up too much. I would definitely check into a clogged radiator as others have mentioned though. How hot has it been up there?
     

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