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Technical Flathead coolant leak

Discussion in 'The Hokey Ass Message Board' started by Chappy444, Jan 11, 2020.

  1. Happy Saturday all.
    I am hoping you guys can help me solve a mystery coolant leak issue.

    30 model A, 51 flatty, Griffin 3" rad (2012 vintage very low milage)
    4lb cap

    This fall I noticed that I had some spray on the driver side fender.
    It spread from the area around the lower left hose and petcock area and spreads back and up the fender... some spots on the edge of the firewall

    It only seems to leak when I am driving as there are no puddles on the garage floor,no matter how long it sits. (Yes there is still coolant in it)

    My first thought was maybe the lower hose was leaking when the pressure built up so I tightened the clamp, wiped everything down and took it for a ride... same problem.

    I thought maybe the left pump was weeping but there is no staining on the pump and how would the coolant get so far forward of the pump but only be down low...

    There is no staining or evidence of "standing" coolant anywhere on the back side of the rad (i.e. the top of the lower tank or fins) so I was thinking it may be an issue around the lower mount bracket or hose. Like a stress crack or something.

    Today I pulled the rad and I can not find any evidence of a leak anywhere...
    I pulled the petcock (it seemed to be tight enough that it wouldnt have leaked) and cleaned it up and checked it over and it seems to be ok... the flange and seat looked good so I put some new teflon tape on it and reinstalled it...

    I am at a loss as to what could be causing it to leak when driving but not leak while sitting, and I hate to put it all back together just to go through the dick dance of getting it apart again...

    Anyone have any thoughts on what could be causing this or have had this same issue in the past?

    Thanks
    Chappy 20200111_142831.jpg 20200111_142807.jpg
     
  2. When you say spray,,,,you are sure it is coolant ,,right ?
    Can you put some dye in it,,,and check it with a light ?
    Sounds like a water pump seal,,,,just guessing.

    Tommy
     
  3. Petejoe
    Joined: Nov 27, 2002
    Posts: 12,264

    Petejoe
    Member
    from Zoar, Ohio

    I had the same issue.
    Found a water pump seal leaking slightly. Only leaked during a drive.
     
  4. Thanks guys..
    Yes. Definitely coolant... green when I clean it off the fender...
    Would a water pump seal blow coolant forward past the pulley to the bottom corner of the radiator? And not leave any evidence on the front if the pump?

    Really hoping it's not a pump leak....lol

    Chappy
     

  5. goldmountain
    Joined: Jun 12, 2016
    Posts: 4,442

    goldmountain

    Since you already have the rad off, you should pressure check it.

    Sent from my SM-T350 using The H.A.M.B. mobile app
     
  6. Sorry,,,,I just reread your post.
    I thought you meant left lower hose and petcock on block.
    No,,,,,,I don’t believe it would blow to the front,,,,,must be the rad leaking some.
    Sorry for the misunderstanding.

    Tommy
     
    lothiandon1940 likes this.
  7. J'st Wandering
    Joined: Jan 28, 2004
    Posts: 1,772

    J'st Wandering
    Member

    Antifreeze coming out of the overflow hose on the radiator?
     
    55styleliner likes this.
  8. I’ve seen it where a rad will get a teeny tiny leak in the core, and leak slightly once coolant is flowing but seal up once the system get hot and the metal expands.
    The rads out!
    Take it to a rad shop and have them leak test it in there tank.
    for what it’s worth and if they find a leak to fix it, your probably all in well under 200 bucks, if not closer to 100.


    It’s out now so might as well confirm it’s all good.
     
    sidevalve8ba likes this.
  9. kjvma131
    Joined: Jan 10, 2014
    Posts: 31

    kjvma131
    Member
    from New Jersey

    Pressure test the radiator in some water. A tub or something and look for the bubbles. Block off the upper and lower ports. Pump it up a little higher than cap pressure and see what happens.

    Sent from my SM-G960U using The H.A.M.B. mobile app
     
  10. Well. Looks like I have a small crack along the weld on the lower mount bracket... it would only leak when the car was running I am guessing it was the vibration flexing the crack open.
    I will try to get it welded up this weekend and then revisit the mounting... it was sitting on springs so I am not sure how this happened...
    Thanks for all the advice
    Chappy
    20200117_170526.jpg 20200117_170535.jpg
     
    lothiandon1940 likes this.
  11. Petejoe
    Joined: Nov 27, 2002
    Posts: 12,264

    Petejoe
    Member
    from Zoar, Ohio

    Easy fix. A good problem.
    The weld looks to be alittle cold and missed hitting the seam. Poor fusion.
     
    lothiandon1940 and clem like this.
  12. clem
    Joined: Dec 20, 2006
    Posts: 4,190

    clem
    Member

    Pete joe put it more politely than I would have..............
     
  13. Next time before you pull everything apart visually looking for a leak, use a pressure tester connected to the radiator. Pump the tester up to cap pressure and start looking for leaks. Saves a lot of time and frustration.


    Sent from my iPhone using The H.A.M.B. mobile app
     
    Petejoe and lothiandon1940 like this.
  14. Petejoe
    Joined: Nov 27, 2002
    Posts: 12,264

    Petejoe
    Member
    from Zoar, Ohio

    Yep. Those welds may look pretty but most of them are setting on top of the surface instead of blending into the material. I bet the welder used twice or three times as much weld as necessary.
    I never understood why people think stack dimes look good setting onto the top of metal. I bet he was trying to compensate for a poor fit.
    Now these are good welds.
    Good fusion.

    https://i.pinimg.com/originals/54/9c/a5/549ca5da33509d3c6b2fcdb661ce27c0.jpg
     
    Last edited: Jan 18, 2020
    lothiandon1940 likes this.
  15. Cliff Ramsdell
    Joined: Dec 27, 2004
    Posts: 1,343

    Cliff Ramsdell
    Member

    I have a question, just a passing thought.

    How are you mounting the radiator to the frame? I have seen it bolted down and this has caused failures like yours. I use a rubber pad between the radiator and frame along with a spring loaded fastener that allows the radiator to float.

    I’ll look for a picture.

    Cliff Ramsdell
     
    big duece likes this.
  16. Thanks for the input guys.
    The mounting is as follows (working from the bottom up
    Frame
    Rubber pad
    Radiator tab
    Nylon washer
    Spring
    SS Washer
    Castle nut

    Is there a different way to mount?
    I have seen some model T's with a spring on each side of the frame...

    Thanks again
    Chappy
     
  17. Petejoe
    Joined: Nov 27, 2002
    Posts: 12,264

    Petejoe
    Member
    from Zoar, Ohio

    From what I see, I’d guess that’s not a crack but a missed seam along the weld.
     
    Desoto291Hemi and clem like this.
  18. clem
    Joined: Dec 20, 2006
    Posts: 4,190

    clem
    Member

    Sounds like you have mounted it correctly for an early ford.
    I don’t know the recommendations for those, if at all different.
    I just used a rubber piece between chassis and radiator, but haven’t used it much so don’t know how long it will last
     
    Desoto291Hemi likes this.
  19. Sounds like you did it right,,,,,I am with the others,,,obviously a bad weld before

    Tommy
     
  20. Cliff Ramsdell
    Joined: Dec 27, 2004
    Posts: 1,343

    Cliff Ramsdell
    Member

    Same here, sounds like you have it right.

    Cliff Ramsdell
     
  21. And the repair... not as pretty as the original... but the original leaked. Lol
    20200120_195643.jpg
    20200120_201100.jpg
    20200120_202524.jpg
    20200120_215817.jpg
    20200120_215823.jpg 20200120_215823.jpg
     
    alanp561, Petejoe and lothiandon1940 like this.
  22. alchemy
    Joined: Sep 27, 2002
    Posts: 20,407

    alchemy
    Member

    You are a good aluminum TIGer. Have you thought about a bit more to the mount, adding a strap upward to bridge the joint on the side?
     
  23. harpo1313
    Joined: Jan 4, 2008
    Posts: 2,584

    harpo1313
    Member
    from wareham,ma

    That would beef that corner up and spread the shock up the side and off the weld edges.
     

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