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What to do with/about a blown head gasket on 402 BB? ~UPDATE~

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Zeus33rd, Aug 31, 2002.

  1. Zeus33rd

    Zeus33rd Smarter than you GMOTM Winner

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    Just picked up an 82 short bed with a TBI 402 BB. For $300. /forums/images/icons/grin.gif Has a blown head gasket. I hoping thats all atleast. It ran enuff to drive it on and off the trailer. Doesn't make any knocking noises or anything, Just spews water and steam outta the left side exhaust. And the oil is milky...So whats the first step in figurin out what to do first? I'm crossin my fingers and hopin the head and block are ok. Just want to know what to look for and what to look at when I start tearin it apart. Should I just replace the head gaskets and see what happens?
     
  2. Mr.Chevy4x4

    Mr.Chevy4x4 1/2 ton status

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    Re: What to do with/about a blown head gasket on 402 BB?

    Tear it apart! It will be obvious which cylinder the coolant was getting in to. Look close and you should be able to tell where it was coming from. If it is spewing that much coolant then there should be a large gap in the head gasket or a crack in the head or block that is big enough to see. Have fun and good score!!!

    Mike
     
  3. Zeus33rd

    Zeus33rd Smarter than you GMOTM Winner

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    Re: What to do with/about a blown head gasket on 402 BB?

    Yeah, Should be tearin into it soon. I'm definatley crossin my fingers and hopin it's not the block. If it's the gaskets.No big deal. If it's the head, bigger deal, but just an excuse to grab some Edelbrock aluminum Performer heads. /forums/images/icons/smile.gif
     
  4. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Re: What to do with/about a blown head gasket on 402 BB?

    Not to put a damper in your "Edelbrock aluminum heads" plan, I would recommend you NOT to get these heads.

    Check out the World Products Merlin heads instead. They are cast iron but will be better suited for slower driving and daily drivers.

    The Merlins also flow better than the Edelbrocks. They can also be had for a little cheaper, too.
     
  5. zakk

    zakk 1/2 ton status

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    Re: What to do with/about a blown head gasket on 402 BB?

    tear the heads off, see what gives. replace all the old gaskets with new hi-po ones, pray it isn't a crack in the heads or block.

    nice catch!
     
  6. Gold Rush

    Gold Rush 1/2 ton status

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    Re: What to do with/about a blown head gasket on 402 BB?

    I think you should just sell me that truck for $300!!!!!
    First off take off the heads. Second take the heads down to a reputable shop to have them checked and surfaced. Third put em back on!! Don't forget to have the exhaust manifolds surfaced also. You are just asking for trouble if you don't. For around $180 we check for cracks, do 3 angle valve job and surface a pair of heads. So it should be a little cheaper up there to have it done. Not much $ for the insurance of knowing they are O.K.




    David
     
  7. Zeus33rd

    Zeus33rd Smarter than you GMOTM Winner

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    Pulled it apart today. Just a blown head gasket. The heads and block are ok...WOOOHOOO! Also got the numbers and found out what it is. Its one of these..
    3999290....396.......68-69...2 or 4 bolt, Truck
    3999290....402.......70-72...2 or 4 bolt, Truck
    3999290....402.......72......2 or 4 bolt, Passenger

    The heads are...
    3917215....67-68...oval..CLOSED..396, 427, 101cc chamber

    Plus they had full roller Crane rockers. Thinkin I'll just get it goin and slap into the Blazer. Nothin Hi-po really. Just a more or less stock BB. /forums/images/icons/grin.gif Thanks to 4x4High for all the info and help figurnin this out. Thanks Scott. /forums/images/icons/cool.gif
     
  8. Zeus33rd

    Zeus33rd Smarter than you GMOTM Winner

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    Re: What to do with/about a blown head gasket on 402 BB?

    Mr. Chevy4x4....Yeah, it was pretty obvious. There was no gasket at all between the #3 and #5 cylinders. Pretty wicked lookin. /forums/images/icons/grin.gif
     

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