Powered by Team Mondor
Page 1 of 2 12 LastLast
Results 1 to 10 of 14

Thread: Losing coolant out of overflow tank

  1. #1
    Lurker

    Join Date
    Oct 2011
    Location
    minnesota
    Posts
    2

    Default Losing coolant out of overflow tank

    I recently rebuilt my 7mgte, but have been plagued with losing coolant from the overflow tank since day one. Runs fine until I really get on it. The car makes 402 whp, and compressioned tested at 180 multiple times.

    Using arp bolts and a mhg torqued to 95 foot-pounds, and it has been retorque since break in.
    It has always over pressurized the coolant system since day one.

    Block was magnafluxed when built, the head was not tested just shaved and made smooth. Was recently rebuilt and gotten grind jobs, so I assumed it was ok.

    I have changed the radiator caps a few times.

    Car doesn't smoke white or at all for that matter, oil is clean, and radiator fluid is clean

    I suspect I have a cracked head that only shows itself at high boost.

    Is there any other possibilities or suggestions before I rebuild a new head?
    Thanks for the help.

  2. #2
    Dang Dude! No Way Man.
    hvyman's Avatar
    Join Date
    Apr 2007
    Location
    Fullerton,CA
    Posts
    12,579

    Default Re: Losing coolant out of overflow tank

    perform a block test and a cylinder leak down test.

  3. #3
    Lurker

    Join Date
    Oct 2011
    Location
    minnesota
    Posts
    2

    Default Re: Losing coolant out of overflow tank

    Quote Originally Posted by hvyman View Post
    perform a block test and a cylinder leak down test.
    Ok I will try to take care of these test soon as I can. I will probably order my own tools, so once they arrive, I will do these tests and update, thanks for the advice.

  4. #4
    Lurker

    Join Date
    Jan 2012
    Location
    Ann Arbor, MI
    Posts
    18

    Default Re: Losing coolant out of overflow tank

    same exact symptoms, same situation. Did you do those tests? After reading this, i'm going to do the same tests on mine.

  5. #5
    Junior Member
    kdog1988's Avatar
    Join Date
    Mar 2007
    Location
    Florida
    Posts
    71

    Default Re: Losing coolant out of overflow tank

    What rad caps are you using? I was having same problem with cheap parts store caps changed to a Stant cap and no more problems. Also does it boil out or just over fills the tank?

    Sent from my LG-E739 using Tapatalk 2

  6. #6
    Let's go Pens!!
    grsupra87's Avatar
    Join Date
    Jul 2005
    Location
    Conneautville, Pennsylvania, United States
    Posts
    368

    Default Re: Losing coolant out of overflow tank

    I know this sounds pretty goofy, but I had the same problem, and found that the nozzle-holes on the bottom of the overflow cap were plugged with debri's and the coolant was pushing out.
    "89 Supra 5spd Hardtop White Package Turbo
    '87 Supra 5spd Hard Top N/A SOLD!!!
    '12 Jeep Wrangler Zombie Editon
    '10 Custom Fury Chopper

  7. #7
    Lurker

    Join Date
    Jan 2012
    Location
    Ann Arbor, MI
    Posts
    18

    Default Re: Losing coolant out of overflow tank

    I block tested mine: negative. I do have a cheap radiator cap. I will be testing the thermostat, upgrading the radiator cap to a better brand, checking the overflow lines for clogs. If I don't find anything I will do static and dynamic compression, and do more testing on the dash guages.

  8. #8
    Lurker

    Join Date
    May 2014
    Location
    Madison, Wisconsin, United States
    Posts
    21

    Default Re: Losing coolant out of overflow tank

    Kdog brings up a good point, is the coolant boiling out or spilling out? Also is your gauge reading normal or does it fluctuate?

  9. #9
    Supramania Regular

    Join Date
    Oct 2010
    Location
    rochester
    Posts
    1,153

    Default Re: Losing coolant out of overflow tank

    same problem here. fresh rebuild with about 8,000 miles on it. head and block decked, titan mhg, arp studs. recently lost some coolant out of the overflow, temp gauge goes to 3/4 after about ten min, then stays at half. I was thinking about doing a new thermostat and maybe a "good" rad cap.

  10. #10
    Lurker

    Join Date
    Apr 2013
    Location
    York
    Posts
    42

    Default Re: Losing coolant out of overflow tank

    im having the same issue lol

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •