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

Cracked head?

Discussion in 'Discovery' started by MatttheHatt, Apr 1, 2020.

  1. mark D

    mark D Full Access Member

    Posts:
    56
    Likes Received:
    0
    Joined:
    Jul 19, 2013
    Most likely the head gasket. At least you can start there.

    Pull a spark plug and blow air in look for bubbles in the coolant. If it is pushing coolant out the tail pipe like you say, it should push bubbles back into the coolant. May have to find top dead for each cylinder so valves are closed.

    Use a rubber tube inside the spark plug hole to feel when the piston is at on top so the valves are close. Than blow air into the cylinder for each. When you find the cylinder you now figured out part of the problem at least you don't have to do both sides.
     
  2. MatttheHatt

    MatttheHatt Member

    Age:
    36
    Posts:
    8
    Likes Received:
    0
    Joined:
    Apr 1, 2020
    Location:
    US
    It is the #6 cylinder that is steam cleaned so I HG failure shouldn't introduce water into the cylinder.

    I am hoping in the next month I can find time to pull the head and at least pressure test it. (Not exactly sure the shop that decked the heads did that...)

    Sent from my SM-G965U1 using Tapatalk
     
  3. mark D

    mark D Full Access Member

    Posts:
    56
    Likes Received:
    0
    Joined:
    Jul 19, 2013
    (Cheap fix): Go to Harbor Freight if you have one near by and get a cylinder pressure gauge. Its a good idea to know your cylinder PSI anyway and the gauge is about $20 bucks. That way you can know what the other side is doing before you crack the top end open. Yes I have done only one side in a money pinch, but I knew the other side had good compression.

    (Suggest if you have the time and money); Don't just pull the head and slam a new gasket back on. Pay the money to take "both heads" down to a machine shop and resurface and grind the valves. Check the top of the block with a straight edge, and get a new radiator. Most likely the reason you have a blown head gasket.

    One of the biggest issues the Discoveries have with blown head gaskets are heat failure due to clogged radiators or failed fans. Do yourself a favor and at least check your radiator.
     

Share This Page