So I found this horrible link regarding coolant loss without a leak...

Discussion in 'General Chevy & GM Tech Questions' started by T-bone, Nov 6, 2012.

  1. T-bone

    T-bone Rockstar

    I cannot find anymore on this other than the linky right here

    Anyone have this happen to them? is this common knowledge here (but not to me?)

    thanks for the input.

  2. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    I have read about it. I was in the foundry business for a while so I did some research. The bad heads were made by a company called Castech. They have a 706 stamped on the ear of the the head. If you look at the passengerside head, just below the bottom right corner of the valve cover (towards the radiator) will have the number stamped. BUT, not all 706 heads where produced by castech. You would have to pull the valve cover and see if the castech logo is there (the battery looking thing) is this the horrible link? I can hardly see it. I looked at my truck and it has "864" heads on it. Don't know if it came from the factory like that or they were changed by the PO
  3. T-bone

    T-bone Rockstar

    Thanks for that link on the TSB

    horrible in the sense that potential for defective heads and no recall or recourse outside of waranty. Coming off a coolant leak from my water pump I was wrapping up my research and then said Oh crap!
  4. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    I know exactly what you mean. I went through the exact same thing with my 03 yukon xl. I had a really slow water pump leak, from the gasket. It took a while to find it and I had come across the head info at that time. I had just bought the truck and was freaking out thinking I head crappy heads.

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