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rad size

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Paxx, Mar 14, 2004.

  1. Paxx

    Paxx 1/2 ton status

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    would a 350 bored .060 over need a larger rad than a stock 350?
     
  2. 1989k5

    1989k5 Registered Member

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    What is a rad?? If you mean rod, the answer is no. Your old rods will work, but I would have them checked. I always put in new wrist pins and even balance them by weighing all 8 and removing some material to match the lightest one. Also make sure you stamp your rods and caps so they are matched when you reassemble. I however would rather bore .030 or .040 over in case the block would ever need to be rebuilt later for a badly scorred wall or scratch. Good luck!!
     
  3. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Or do you mean radiator? Run a big four core /forums/images/graemlins/thumb.gif
     
  4. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    A good 3 core should be plenty for a mild 350.
     
  5. Paxx

    Paxx 1/2 ton status

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    I did mean radiator. My buddy is having some frusterating cooling issues and we are starting to wonder if the rad is just too small.
     
  6. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    How does the gauge read. Sometimes too hot or too cold would indicate bad thermostat. When they stick open a little it may run too cold. If it don't open at all you'll overheat. I assume you already checked the easy things like belts etc? Are you running water , or a coolant mix? Also check the fan clutch if mechanical fan. If that isn't clutching the engine won't pull enough air to cool it . Hope these thoughts help. /forums/images/graemlins/thumb.gif /forums/images/graemlins/k5.gif
     
  7. Paxx

    Paxx 1/2 ton status

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    hmm they do help. We have no thermostat in it right now just to simplify it a bit. The temp will stay fairly constant for short periods of time and then put of nowhere it will spike up to the danger levels. So then you stop and wait a while, drops down, cruise for a while, then it will spike again. Very frusterating. I'll get him to check the clutch. Is there an easy way to do this?
    thnx~Max
     
  8. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    There are two styles of clutch. One is thermstatically controlled, there is a spring like a choke spring in the center, it should kick on when warm. The other style is centrifigal clutch , it has fluid in it, it works at lower speeds and slows down on the highway. I may be backwards on it, been so long since mine was bad. Someone should correct me if I have it backwards. Hope it helps /forums/images/graemlins/thumb.gif

    BTW you should run a thermostat, it will hold back the water so it can absorb the heat, then open and send it to radiator to dissipate it. May make all the difference /forums/images/graemlins/waytogo.gif
     
  9. skratch

    skratch 1/2 ton status

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    The easist way to check the fan clutch from what I remember is to: try to turn it when the rig is cold and see how much resistance you have, there should only be a little resistance then. Then when the temp spikes like that and the truck is good and hot stop it and try to turn the fan right away again, it should be really stiff like your trying to turn over the engine. If it doesn't have any resistance then it's most likely bad.
    But you really need to stick a thermostat in there too, that will make a ton of difference too.

    If after all that you still have issues, get a large four core or a wide tube two or three core. I have a wide tube two core that supposedly cools as good as a normal 4 core. It does work a lot better than the original radiator, but I'd still like to run a large 4 core. /forums/images/graemlins/waytogo.gif
     
  10. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    BTW you should run a thermostat, it will hold back the water so it can absorb the heat, then open and send it to radiator to dissipate it. May make all the difference /forums/images/graemlins/waytogo.gif

    [/ QUOTE ]
    I agree, The water needs to be held back so that an actuall transfer of heat can take place between the cylinder walls and the water.
     
  11. Paxx

    Paxx 1/2 ton status

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    thanks for the replies guys, I'll give all that a shot.
     

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