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I want to go from a 3core to a 4 core rad>>>

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by Burt4x4, Aug 6, 2001.

  1. Burt4x4

    Burt4x4 3/4 ton status

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    Hey gang my 3core radiator just isn't giving me the cooling I need. I am gonna swap in a 4core.
    Please tell me what is needed to do the swap? Do I have to change the top mounting brakets? What is a good donor Chevy for a 4core? I would think I need a 4core from another 72 mabie a 1ton or Sub???
    Any info would be GREAT!!!!

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
    <a target="_blank" href=http://www.geocities.com/baja/5099>www.geocities.com/baja/5099</a>
     
  2. Triaged

    Triaged 1/2 ton status

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    I don't know what it is from but I have a 4 row in mine (it was in there when I got it). It has the same top brackets in factory holes (there are 2 sets on each side mine are on the outside). You can also have yours recored to 4 row it is cheeper than a whole new rad.

    Also when is it heating up? On the hwy. or going slow wheelen and around town?

    '71 Blazer CST w/ a 400sbc, 4" lift, 36" Supper Swampers, and alot of rust
     
  3. Burt4x4

    Burt4x4 3/4 ton status

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    Yes it is getting hot when wheelin and the RPMs are at 3000 for log periods, like long hill climbs on the trail. Also on the Hwy when going up long hills and you have to push harder on the gas to keep the speed up. I have allready gon thru my cooling system so I know it is working at it's full potential. I'll look into getting my 3row re-cored to 4!! Thanks

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
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  4. arq

    arq 1/2 ton status

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    burt,
    i did the swap about a yr ago. i went from a 2 to a 4 row. the 2 row tanks were the larger ones so when i put in the 4 row i had no problems.
    i know you said you went through your system, anyhow.
    do you have a good thermostat. usually when not there the water goes through the system too fast that is does not stay in the rad long enough to cool down. this also happens when a lower temp thermos is put in like swaping in a 160 deg for a 180. also putting in a higher temp thermo(190) helps.

    my 2 centavos.

    ARQ.

    PS: you're gonna love that 4row

    1-72 4x4 CST Blazer
    2-71 4x4 CST Blazer
     
  5. ImpalaSS

    ImpalaSS 1/2 ton status

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    you can get a brand new modine 4 core for about 200 bucks.... and if your brackets dont work www.gmcpauls.com sells new 4 core ones
    i have one of the modines in one of my trucks and it works great.... also you can use the raditor from a 73+ chevy if you use a 73+ bottom raditor hose!

    68 SWB 4x4 1 of 1,449 made 327, 465 4 speed, rockwell tcase, edelbrock performer intake+carb, MSD pro billet http://communities.msn.com/68K10
     
  6. smp

    smp 1/2 ton status

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    I think you can find the 4 core from a big block equiped truck i have also heard that the disiel rad. is larger than the big block ones but i'm sure it would take some work to mount.

    [​IMG] [​IMG] [​IMG]
     
  7. ImpalaSS

    ImpalaSS 1/2 ton status

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    4 cores were supposed to come in big block trucks and ones with factory a/c (but dosnt mean that 100% of them have 4 cores...)

    68 SWB 4x4 1 of 1,449 made 327, 465 4 speed, rockwell tcase, edelbrock performer intake+carb, MSD pro billet http://communities.msn.com/68K10
     
  8. k5blazerus

    k5blazerus 1/2 ton status

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    look in a deisel pickup that is a for shure 4 core in them

    IF its not broke , break it and upgrade it.
     
  9. 71RestoRod

    71RestoRod 1/2 ton status

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    If you're going from a stock 2 or 3-core to a stock 4-core you will need both the upper and lower mounts for the 4-core w/ the rubber pads. If you pull the radiator from a doner, grab the mounts! Otherwise, LMC and most all of the other 67-72 Chevy truck parts houses carry them.
     
  10. Burt4x4

    Burt4x4 3/4 ton status

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    Hey thanks guys!! I have some ideas now. Time to go hunting....

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
    <a target="_blank" href=http://www.geocities.com/baja/5099>www.geocities.com/baja/5099</a>
     
  11. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    "...Time to go hunting?...."

    I think not! It's time to get your new 35" SSRs installed and take a bunch of "Before" and "After" photos. Then it will be time to update your website with these new pics!!!!!!

    There are some "future" SSR's owners who have been waiting to see how things turn out on YOUR rig!

    [​IMG]

    -Greg72
     
  12. Burt4x4

    Burt4x4 3/4 ton status

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    hahaha, don't worrie the SSR fund is not being affected by this. Very soon I will have them.....and yes I will share the pics!


    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
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  13. Klef72K5

    Klef72K5 1/2 ton status

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    Did you put on a flex fan? I did on my Jeep and I ran hot all weekend long in the dunes. The problem was I was turning too many RPM's allowing the fan to straighten out and not going fast enough to let the air go through the radiator climing the sand dunes. My Blazer has a flex fan too with no shroud. It will never be cool when I get it rewired! I'm going to put on a stock fan and shroud for that problem

    <a target="_blank" href=http://wsphotofews.excite.com/031/rw/Jo/og/t488200.jpg>http://wsphotofews.excite.com/031/rw/Jo/og/t488200.jpg</a>
     
  14. ryanNC

    ryanNC 1/2 ton status

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    I was just reading in the new Peterson's that an aluminum 2core radiator would cool better than a regular 4 core and is lighter to boot!! But that whole mount problem arises...... screw it, make new (and better) mounts, add a double electric fan and your set for life!

    "need more <font color=green>cash</font color=green>"
     
  15. arq

    arq 1/2 ton status

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    Burt,

    remember Steve Chin's alum radiator. you may want to go for that. I think his rad was in the 200 range.

    ARQ.

    1-72 4x4 CST Blazer
    2-71 4x4 CST Blazer
     
  16. Steve_Chin

    Steve_Chin 1/2 ton status

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    Steve, screw the 4-row radiator. When I holed my 4-row, I looked into what it'd cost to re-core or replace it. Too freakin' much. I got a Rodney Red custom aluminum radiator for cheaper than a stock 4-row replacement and I couldn't be happier with it.

    FWIW, all of the thermal transfer equations I have seen don't care about coolant flow rate through the radiator (FWIW, I am running a Robertshaw high-flow thermostat). They do care about getting enough cool air through the radiator to keep the core cool. What kind of water pump is in your Blazer? If it's a stock replacement, it likely has a stamped steel impeller. Those cavitate at higher RPM and reduce flow. You can reduce the cavitation effect by riveting a steel disc to the back side of the impeller (that's what the Flow-Kooler water pumps have in them). Another thing to look at is the thermostat. The cheapo replacement thermostats get forced closed as coolant flow rate goes up due to the valve design. Those are really bad for high-performance work, which is why I only use the Robertshaw design with the reverse valve and bigger opening. Also, look into your radiator to ensure that all of the tubes are flowing optimally and are transferring heat appropriately. Ensure that there are no air flow blockages...
     
  17. Burt4x4

    Burt4x4 3/4 ton status

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    I have heard that a aluminum 2row will cool better than a stock 4row.
    My 3row was rodded out last summer and I replace my water pump with Summit highflow. I do run Robertshaw stats, the one I have in there now is stockstyle @ 185. I do have a Highflow stat too just haven't put it in yet.
    For the most part my cooling system works great it's just when my rig is workin hard in the summer heat (like at Hollister climbing thoes long up hill trails in granny low spinning 3000rpm +-) my motor shot up to 220. On the Hwy it never goes above 195 in the summer except when I'm trukin up to the serrias on a Mtn Hwy like 108 the temp will rise to 205 or so.
    I was thinking if I had a bigger rad that holds more coolent it would do a better job keep in my rig cool.??
    So should I look into an aluminum type?
    Some info on who sales them would be cool and what mods I would need to do to get it installed. ANy part #'s and such would also be great!!
    Thanks

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
    <a target="_blank" href=http://www.geocities.com/baja/5099>www.geocities.com/baja/5099</a>
     
  18. Steve_Chin

    Steve_Chin 1/2 ton status

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    Steve, I never see my coolant temperature go more than one needle-width above the top of the "cold" box at the left side of the stock gauge. I would say that the aluminum radiator does a good job of cooling the engine off. I got my radiator from Jerry Wirth at Rodney Red (<a target="_blank" href=http://www.rodneyred.com>http://www.rodneyred.com</a>). It was less than going with a cheap-o 4-row unit. Tell him you want the same radiator I eventually ended up with, but you want the upper hose bung to be 3/4" lower on the tank and the lower bung needs to be angled up 20 degrees.

    FWIW, your engine temperatures are not excessively high. I thought that you were seeing water temperatures above 220. A little more heat rejection capability is a good idea for those hot days when you're towing something, though.
     
  19. gokartergo

    gokartergo 3/4 ton status Staff Member Moderator

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    I just got back from going up 108. I went up to Long Barn. I was towing my tent trailer. I was hitting 210 going up. I have a brand new 4 row rad. I know 210 isn't that bad and as soon as I was going down hill it would cool down. But I don't like it. I'm thinking of going with a push fan. What do you guys think......Dan

    If it ain't broke.......Don't fix it....
     
  20. Burt4x4

    Burt4x4 3/4 ton status

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    Well I don't think more air will do the trick. I'm convinced that when our motors start working hard, towing or trail crawlin up hill, all the torque and just plain work is gonna heat up things. So I'm thinking if I had a rad. that was made for a BBC or heavy heavy duty towing then the 350 would remain in and around 200 when under very heavy loads for long periods of time.
    I whent wheelin this weekend up out of Kyburs off Hwy 50 and out there climbing long hill trails my stupid tem was hittin 230 so I shut down and let the fan run then start it up watch the temp drop shut it off wait some more start it up watch it drop some more etc.........
    I'm tired of messin around so I'm gonna buy the biggest damn radiator I can fit under my hood!!
    Steve I will call your buddy and find out if he has what i'm looking for!

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
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