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4 Core Radiator Help!!!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Waxer, Jun 22, 2000.

  1. Waxer

    Waxer 1/2 ton status Author

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    I am going to install the 4 core radiator in my K5. I read previous posts that one from an 86 1 Ton 4X4 with 454 is what I should ask for. I called Autozone and they are $175. I also read that I need to upgrade my upper radiator support, but nobody posted the part # or which vehicle it has to come from so I can ask the dealer for the right part. Could someone please tell me which year, model, chevy to ask the dealer for the upper rad support for? thanks. Possibly a GM part # for it? thanks again
     
  2. J.R.

    J.R. Guest

    i put a 454 in my 85,and i also added the 4core radiator,i did not have to do any mods to the supports.she fit perfect.one thing i did notice is to flush out your new radiator.they will have dust and resadue in them from the factory.i also got rid of the old factory clutch fan,i put on a flex fan and put spacers in to get the new fan about 2 inches from the radiator.on the hotest day my 454 never runs more than 155 deg.but i also have a weiand hi-flow waterpump and a 170 hiflow thermastat...

    BIGBLOCK MAN
     
  3. DMK

    DMK 1/2 ton status

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    Put 4 core radiator in 78 k-10 no mods. Bought mine from radiator shop for 168.00. Just told them I wanted the heayduty radiator.
     
  4. Shawn

    Shawn 1/2 ton status Premium Member Author

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    In my 87, the radiator was lower than the radiator support. I had major overheating problems so I found the largest radiator offered in the 81-87 trucks. This radiator was much taller than the stock 87 Blazer radiator not to mention it was a 4 core. I DID have to replace my upper radiator mounts with a 1 piece top mount and shroud from a 3/4 / 1 ton truck. I think the rubber mounts were seperate too. I believe the older Blazers have taller radiators but I'm not too sure on that. Sorry, I don't know the GM part #'s. I attached a few pictures. Hope this helps.

    Shawn
    87 K5
    454
     
  5. Shawn

    Shawn 1/2 ton status Premium Member Author

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    Another pic.
     
  6. Espen88k5

    Espen88k5 1/2 ton status

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    When I did my radiator the new radiator sat 1 inch lower. I cut some gardenhose and made a tight fit that way..
    Dont leave it ratling or else the shroud-clips will work loose and then the [censored] will hit the fan!!

    [​IMG]


    <font color=blue>Espen88k5 at: </font color=blue>http://espen.coloradok5.com
     
  7. Impex

    Impex 1/2 ton status

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    I installed a 4core in my 78 truck and all i did was get a 4core from the same year as my truck( '78) and then went to Chevy and asked for a upper radiator support bracket for a '78 400(4core) engine and it bolts right up and like shawn said earlier you should buy the (4) rubber bushings from chevy also there only like 2.50 each
     
  8. K5 NUTT

    K5 NUTT 1/2 ton status

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    Waxer...i am assuming your K5 had the small rad the had a upper mount that bolted to the core support about 2-3 inches below the top of the core support. If you are upgrading from that particular style to the big 4 core then you will need the upper plate that bolts to the top of the core support. Also you will need to install 4 nut-zerts to bolt it down...you can get the factory origianls but they can not be installed unless you have a pneumatic gun such as we use to install HUCK bolts into the frames of semi's. Then you will need 4 new rubber bushings for the rad to sit into to keep her from moving around!

    My 79 allready had the full size 4 core in it when purchased but due to the az summers the metal was severely heat soaked so basically she was dead. A good working radiator should net a 10 to 12 degree drop across the radiator if working properly. Anyways i talked to a friend who gives me cost on parts so i installed a GM replacement radiator. They are no longer selling the copper style and now sell a replacemet that has the aluminum core and plastic side tanks. Well it wasn't a direct bolt in but by using the tallest rubber mounts that GM used in the early 90's and modifying them slightly and tweaking the trans lines she fits great! The upside to this is sitting at a traffic light here in Phoenix she never gets above the 1/4 mark on the gauge.

    Hope this helps.

    AZBLAZER

    1979 K5
    1976 K5 Chalet
    1972 K10 Suburban
     
  9. BigBadBowTie

    BigBadBowTie 1/2 ton status

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    <font color=purple> I installed one out of a full size motorhome. I went to a rad shop he took the measurements of my stock three core. Then looked through his books (not computer) & found one that had the exact same height & length, it was just approx 1 1/2" thicker. I then went to GM & ordered rubber bushings that fit that radiator" I then cut my upper mounts in half then welded a 1 1/2" piece in the middle. Works great. If you want the part number of my radiator, I can get it to you this evening.</font color=purple>
    [​IMG]



    Rick
    86 K-5
    http://www.BigBadBowTie.ColoradoK5.com
     
  10. Zack

    Zack 1/2 ton status

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  11. Hey Zack, any ideas on whether it'll fit directly in or the hole will need alterations?
     

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