3fe coolan system overpressurizing?

Discussion in '80-Series Tech' started by Arjuni, Aug 10, 2018 at 11:25 AM.

  1. Arjuni

    Arjuni

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    Hi

    I posted a thread a few weeks ago similiar to this and I am looking for a second opinion/hoping to steer the convo in a different direction.

    I have a 3fe fj80, and recently replaced the thermo, fan clutch, water pump, and rad. The rad was leaking on the top seam.

    Fast forward only one month, and I have my new rad leaking on the top seam again, in multiple spots.

    New fluid and cap also.

    So, barring the idea that I just happened to get a CSF radiator lemon (could be possible) what could be causing my coolant system to overpressurize and destroy these radiators?

    I did check the coolant for combustion gasses, none present.

    Also I should note that the last radiator was bulged, making me think that overpressurization is the culprit.

    Thanks yall
     
  2. CJF

    CJF

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    Did you replace the T-stat with new OEM after your last thread?

    And can you see coolant move into the overflow as the engine warms, and then return once it's cool?

    If so, face it: You got a crap radiator.
     
  3. Marco Lau

    Marco Lau

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    did you replace the radiator cap?
    Also, start the engine with the cap on for a minute or so, then open the cap and see if the system is pressurized? It should have a slight rise in coolant as it expands, but not bubbling with gas and high pressure, could be a sign of exhaust gas getting into the system.
     
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  4. Dave 2000

    Dave 2000 Not all Land Rovers are useless! SILVER Star

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    Radiator cap is responsible for pressure control, do you have the right one installed, does it work?

    I try not to lean on the header tank when working on vehicles (not just 80's), I think that may be the cause of many top tank failures?

    Regards

    Dave
     
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  5. jdayment

    jdayment SILVER Star

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    Radiator cap or thermostat I had a thermostat get stuck shut that caused my radiator to blow out I should have caught it earlier lead to many more problems.
     
  6. Dave 2000

    Dave 2000 Not all Land Rovers are useless! SILVER Star

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    A jammed thermostat will cause overheating and pressures to rise, but those pressures are released by the cap.

    If your rad, hose or whatever fails before a good working cap releases the pressure then they were already past their best.

    Regards

    Dave
     
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