1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Coolant on intake manifold

Discussion in '6.9L IH & 7.3L IDI Diesels' started by dgr, Aug 22, 2019.

  1. dgr

    dgr Full Access Member

    Posts:
    662
    Likes Received:
    58
    Joined:
    Aug 5, 2012
    Location:
    sac town
    Went out yesterday and noticed a small puddle under the passenger side of the engine. I drove the truck and this morning, I noticed a much larger puddle. I was short on time and only took a quick glance. I noticed coolant still dripping around the starter and I noticed coolant puddled on top of the rear glow plug on the passenger side.

    Before I start digging into it this evening, is there a common area for our 6.9s to leak coolant here?

    Thank you
     
  2. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

    Posts:
    7,581
    Likes Received:
    5,736
    Joined:
    Jul 27, 2015
    Location:
    Bulverde, Texas
    Check your glow plug controller at the back of the head. It’s probably coming apart
     
    Alwaysreadyrob and dgr like this.
  3. dgr

    dgr Full Access Member

    Posts:
    662
    Likes Received:
    58
    Joined:
    Aug 5, 2012
    Location:
    sac town
    @Thewespaul thank you for the reply. I dig deeper and here's what I've got

    The controller is on the driver's side. My leak is at the rear glow plug on the passenger side. The leak is directly behind (towards the center of the truck) the glow plug. It's leaking between the head and the intake manifold.

    From what I can tell these engines have a dry intake with no coolant flowing through them. However, looking at pics of the heads, it appears there is a water passage in that area that is plugged with an (aluminum?) cup and it is blocked off by the valley pan. Can someone confirm there is a water passage there? I can't imagine how else water is coming out of that area.

    Hope I can post a pic in the thread. Of it works, it's coming out the seam between the silver intake and the head in the pic. Image4929901507168433947.jpg Image4929901507168433947.jpg
     
  4. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

    Posts:
    7,581
    Likes Received:
    5,736
    Joined:
    Jul 27, 2015
    Location:
    Bulverde, Texas
    The 6.9 heads do have a coolant passage behind the intake manifold that is sealed by the valley pan, sounds like you need to replace the valley pan.
     
    dgr likes this.
  5. dgr

    dgr Full Access Member

    Posts:
    662
    Likes Received:
    58
    Joined:
    Aug 5, 2012
    Location:
    sac town
    Sounds like fun!

    Do you know if there is a cup plug in that hole that should also be replaced or is it just the valley pan sealing it off?
     
  6. dgr

    dgr Full Access Member

    Posts:
    662
    Likes Received:
    58
    Joined:
    Aug 5, 2012
    Location:
    sac town
  7. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

    Posts:
    7,581
    Likes Received:
    5,736
    Joined:
    Jul 27, 2015
    Location:
    Bulverde, Texas
    Yep, later models got freeze plugs and then stainless balls pressed in.
     
    dgr likes this.
  8. TahoeTom

    TahoeTom Supporting Member Supporting Member

    Posts:
    660
    Likes Received:
    28
    Joined:
    May 19, 2010
    Location:
    S. Lake Tahoe, CA
    My machine shop was able to thread pipe plugs into those ports. Sealing the ports with the valley pan was not ideal so the change was made to plugs for the 7.3

    DSC00109.JPG
     
    dgr likes this.
  9. dgr

    dgr Full Access Member

    Posts:
    662
    Likes Received:
    58
    Joined:
    Aug 5, 2012
    Location:
    sac town
    Interesting. My 6.9 has oval holes. If I ever pull the heads, I will see about making them more roundy for pipe plugs.

    Replacement wasn't too bad. Of course the weather had to nudge back up to 100. I got it all torqued to 28 ft lbs and let it sit for the night. I'll torque to 35 and start putting everything back on. Sure is shiny. I should probably spill some oil on it to keep it from rusting. Maybe throw some old o rings , toothpicks and gasket pieces under there.....

    IMG_20190823_202844403~2.jpg
     
    stealth13777 likes this.
  10. Macrobb

    Macrobb Full Access Member

    Posts:
    2,228
    Likes Received:
    1,126
    Joined:
    Jun 12, 2016
    Location:
    North Idaho
    So... I once did modify a set of heads for some plugs. I think they were 1/2" or 5/8"?
    Anyway, I used an endmill to bore out the oval hole and make it fit the plugs. Then, I installed the plugs with a little RTV, just in case.

    The plugs worked fine. However... despite trying to be careful, and vacuuming everything, I must have ended up with a few chips still in the intake runners when I reinstalled it.

    I found out later when I removed the heads on that motor, because I had a couple of nice score marks up and down each cylinder from the chips...
     
    dgr likes this.

Share This Page