How widespread is the Castech head crack?

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by jutgin, Jan 1, 2012.

  1. jutgin

    jutgin New Member

    I just wonder how big of a problem this has been since there must be 10's of thousands of these motors out there.
    I guess I am just concerned since I just bought one with the 706 casting.
    Should I nip it in the bud and go ahead and replace the heads now?
    I do have another question that may be easier to answer/talk about.
    Are all the 706 heads made by Castech? Or is that why you have to look inside to see the Castech marking?
    I know I have the 706 cause I can see it clearly on the outside of the head passenger side.
  2. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    I found this about identifying the Castech heads. It does not indicate the 706 marking in the document. I have been searching for a few days and it seem as if no one has the answer to the question about only castech making the 706 head. I did locate some pictures that showed different font for the 706 number, but those posters never indicated if they found the castech logo inside.Sorry I can't help more.
    Last edited: Jan 3, 2012
  3. jutgin

    jutgin New Member

    Thank you for the reply, I think I found the same thing you did. Seems like you must look inside to properly identify.
    The good news for now I guess is that I'm not loosing coolant. So nothing urgent at this time.
  4. mad1500hd

    mad1500hd Rockstar 100 Posts

    i don't know if mine falls into this category...i have the 6.0 motor and just recently found a hairline crack on the passenger side head and was losing coolant...good thing it was under warranty...only cost me $ it could've been worse.

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