Another freeze plug!!!!

Discussion in '6.9L IH & 7.3L IDI Diesels' started by beckty85, Feb 12, 2018.

  1. beckty85

    beckty85 Registered User

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    This all started with this thread https://www.oilburners.net/threads/

    Truck is back together completely and I have just been working out little bugs here and there.

    They new water pump is leaking out the weephole. It sat for about 2 years and I ran it dry for about 30 seconds. That's not the big problem. This all started with a freeze plug behind the flex plate so the tranny had to come off.

    Now the freeze plug on the pass side partly behind the motor mount is leaking. (Backstory- previous owner lost water pump, let truck sit for 2ish years without draining the block.

    Considering these options right now

    1. Drill and tap in place for a boss 429 style threaded plug.

    I'll have to measure the distance tonight, but I think it's doable. The tap is 4in long.

    2. Clean it up really good and belzona the plug (think jb weld, major industrial. 1500 a box stuff. But I have some.)

    3. Pull motor.....

    4. I've heard of people removing the motor mounts and jacking the motor up. I have the install tool. Just not sure I can get the clearance to properly install it.

    Any help or advice is greatly appreciated.
     
  2. DrCharles

    DrCharles Full Access Member

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    I recommend 1 or 4. Don't goop it up with epoxy, even the good stuff. Hope you don't have to pull the engine!

    Probably not what you want to do, but consider doing all the freeze plugs. If they're not leaking now, I'd worry that they'll start once you put the truck to work...

    On occasion with other vehicles I have made a hole in the body to reach a tool through (such as the inner fenderwell for access to #6 spark plug in my big-block Dart with headers. Would be next to impossible to reach unless you had two elbow joints, even from underneath).

    I'm a recent first-time IDI owner and my truck has been waiting for parts for much of that.
    Is making a hole an option for you?
     
  3. Thewespaul

    Thewespaul Supporting Member Supporting Member

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    Pull the engine. Like said you’re going to keep having issues with freeze plugs if you don’t fix the rest. Just makes more sense to make it easy and do it while the engine is out
     
  4. icanfixall

    icanfixall Official GMM hand model

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    Please recall where you started this project. A rusted out freeze plug. Now you found one more bad one. So you have 5 more that are truely suspect.. Time to pull the engine and do this job correctly.
    I like the idea of drilling out the block for the screw in Boss 429 plugs but. Thats a huge job. You will have to purchase the tap and then modify it because it will not cut the threads correctly. Its too long and bottoms out on the cylinder liners. So cutting off some of the tap threads is needed. How much I can't tell you because I do not know the depth on the tap when it contacts the cylinders. So drilling out a test piece of cast iron on a bench is the way I would do it. ALL pipe threads are a taper fit. This means to tighter you screw them together the more interference fit happens to create a thread seal.
     
  5. beckty85

    beckty85 Registered User

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    I am going to start getting everything together to pull the motor. Tried to order a new complete set of plugs from who I got the first ones from and they only had 6.

    For shits and giggles I'm going to try this weekend to see if I can take a motor mount loose and get a decent angle at it. If so I may put one in and buy some time.

    Has anybody successfully done it without pulling the motor, specifically the one under the motor mount.

    Thanks
     
  6. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    I can't be sure without looking, but I'd think that you'll have issues with hitting the crossmember trying to replace that one with the engine still in the truck. I hope you can do it though. Good luck.
     
  7. Thewespaul

    Thewespaul Supporting Member Supporting Member

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    Does it leak all the time or just when at temp? You may get away with putting a 7 psi cap on if so.
     
  8. pelky350

    pelky350 Full Access Member

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    Depending on how much time you need this works really well with cooling system issues. I limped my radiator along with this and did this with my bronco when I had a leaking water pump. It's worth a shot to buy some time
     
  9. beckty85

    beckty85 Registered User

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    Considered running a zero psi sytem with Evans coolant. Will more than likely do that when I do a full rebuild.

    It didn't start leaking until yesterday, was moving it to the shop to work on fuel system(gauge not working). Never got up to temp.
     
  10. Joseph Davis

    Joseph Davis Full Access Member

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    I know that if one freeze plug is bad their all Bad. Best bet would be pull motor and replace them all. Good luck, but I would really think about it before trying to tap cast iron. I hope every thing Goes Good.
     
  11. beckty85

    beckty85 Registered User

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    I plan on pulling and more than likely doing a rebuild on the motor this summer. So if I can buy some time that would be good.

    Not working the truck hard by any means so I'm going to put a 7 psi cap on and see if I can use it for a bit while I get everything together.
     
  12. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    So how did you get a rusted out freeze plug in the first place? The factory ones are stainless steel and won't rust.
     
  13. beckty85

    beckty85 Registered User

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    Not rusted .just blown out. Previous owner lost water pump. Took it all apart in a super sloped driveway and never drained the block. Let it sit for 2 years that way and it popped one In the bell housing.
     
  14. beckty85

    beckty85 Registered User

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    I was told I was buying a truck that needed a water pump installed . I tend to believe that he was completely truthful .
     
  15. beckty85

    beckty85 Registered User

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    I also pressure tested the coolant system after installing the freeze plug behind the flex plate, before putting the tranny back in. System held 15psi no problem.

    Either way, picking up a hoist this weekend and I'll start planning for the inevitable, but going to stretch it out for a bit.
     

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