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Cracked heads

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by schwinnd, Feb 18, 2002.

  1. schwinnd

    schwinnd 1/2 ton status

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    Just wondering what would cause the heads to crack. I thought I blew a head gasket but after I took the head off I found 3 cracks around the #5 exhaust valve, and when I took the other side off, the #4 exhaust valve had a nice crack in it also. I just bought some new heads for it which I'm about half done putting them on, but was just curious to know how that happens. Is it extreme heat? improper torque? what gives?

    Thanks

    Dave

    Just collecting rusty mid-70's chevy's
    1976 Blazer, 1975 Vega SW
     
  2. k5blazerus

    k5blazerus 1/2 ton status

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    DO you have a heavy right foot.
    colin

    Save the whales Harpoon a fat chick.
     
  3. schwinnd

    schwinnd 1/2 ton status

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    Oops, I forgot to list that as an option [​IMG]. I have only had the blazer about a year and its only been running about 5 months of that, but I've recently heard some history on it from a guy I work with who used to work for the guy I bought it from. Anyway, the son of the guy really abused it so I'm thinking that is where most of my problems are coming from.

    thanks

    Just collecting rusty mid-70's chevy's
    1976 Blazer, 1975 Vega SW
     
  4. newyorkin

    newyorkin 1 ton status

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    Overheating, I think. Make sure you flush your cooling system when you get the new heads on, but it may just be from running it hot and/or lean too many times. I don't remember the cylinder positions by number, but I know the rear two (closest to the firewall) are usually the hottest.

    Ratch
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