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hosed

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by ed rex, Oct 22, 2001.

  1. ed rex

    ed rex Registered Member

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    Good day! Been dealing with overheating issues ever since dropping the 454 in. Due to the size, the fan shroud had to be whittled down to no more than a glorified bug shield. Some of the gory details I posted in the 'putting 396 in jimmy' thread.

    Anyway, after receiveing several suggestions I decided to get on this issue with the hopes of putting it to bed once and for all. Yesterday, at the suggestion of the local radiator shop, I plugged the bypass. Then, using a pair of 1/2" thick rubber mudflaps, I 'custom fit' a shroud by cutting up the flaps and attaching the pieces to the existing piece of fan shroud. This worked fairly well and the truck now idles forever at around 200 degrees, cooler than it's been for about 6 years. Regrettably, the mudflap assembly did not have the rigidity to withstand rapid acceleration and started flapping around. The flex fan caught it, knocked a chunk off which rocketed into the radiator at what I can only estimate to be about 900 feet per second. Now I have a radiator with a hole in it and a bent fan. But I'm on the right track!

    My question is how should the heater core hoses be routed? Current setup is that one hose goes to the water pump and the other goes to the intake manifold. Partner of mine was over yesterday. He's got a Mustard '71 Jimmy and we got to looking at his hoses. One of his heater core hoses goes to the water pump but the other goes to a nipple directly below the upper big hose input to his radiator. I too have this nipple but it is plugged. Should I move the hose to my input manifold and plug that in favor of the radiator hookup?

    Next question: I have a tranny cooler bolted in front of my radiator. The lines go directly to and from the tranny to this cooler. Again, we got to looking at my buddy's Jimmy. His tranny lines go into and out of the radiator via the traditional radiator input and output fittings. Should I reroute my tranny cooler lines to go through the radiator as well as through the tranny cooler? If so, does it matter which one I go through first?

    Thanks!

    Ed
     
  2. Steve_Chin

    Steve_Chin 1/2 ton status

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    Ahhh.. I thought that putting a functional shroud on it would help an idle overheating problem. Maybe you can piece something together that will work out of a 2WD fan shroud and some plastic to lower it so it fits around your fan. Remember that the blades should be no more than about 3/4 into the shroud and no less than about 1/8 into the shroud (depending on the shape of the blades and their fit to the shroud). Bummer that your experiment holed your radiator. I did the same thing to my 4-row radiator when I was drilling the radiator support so that I could fit my A/C condenser to it (which is why I now have the Rodney Red aluminum radiator).

    My heater core (non-air) is plumbed just like yours: Hose from the intake manifold coolant crossover goes into the heater core inlet, hose from the heater core outlet goes into a nipple on the side of the water pump. My buddy's '72 with A/C is plumbed more or less the same way with the addition of a vacuum-operated water cut-off valve inline between the intake manifold and the heater core. In any event, changing the source of hot water to the core (intake manifold vs. radiator inlet tank) won't make a hill of beans difference in how your engine cools. It might slightly decrease the heat output of your heater core because the water loses just a little heat as it travels through the thermostat, upper hose, then into the inlet tank of the radiator.

    WRT the tranny cooler, most of the cooler manufacturers recommend that the fluid from the transmission flows into the in-radiator cooler first, then into the auxiliary cooler, then back to the transmission. I know several guys who have completely bypassed the in-radiator cooler and have been running just fine like that for years, but personally, I'd run it the way the manufacturers recommend.
     
  3. bouncytruck

    bouncytruck 1/2 ton status

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    Have you considered and electric fan(s).

    '69 K-5/350/TH350/35's & 6" Lift
     
  4. frito

    frito Registered Member

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    i would also try going to the local junk yard theres alota fan shrouds there and theres more than likely gonna be one that fits pretty decent in your truck, on the hole in your raidiator part can you see the hole ? because if you can see the hole you can fix it your self easily i put a hole in my radiator in my K5 (with a damn wrench i droped in the shourd DOH! ) and it was pretty big and at the edge of the row closest to the motor and i just got out some electronics soilder and a high power heat gun ( for like shrink wrapping its like a realy hot hair dryer) i cleaned the area that was broke down to the metal heated it up with the gun and fed the solder in and filled the hole but dont put in so much that you clog the row with solder and it has worked great for over a month also i have friends that have gone from a cluch fan to a flex fan and started overheating cuz they dont cool as good as a cluch fan ..... i have one of the solid high perf fans on my truck it looks like a flex but dont flex ... seems to work good for me

    frito
     
  5. ed rex

    ed rex Registered Member

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    Yup....tried the electric fan route. Didn't work. It was a big one too. Still have it in the garage. As far as the hole, it's really a smallish pinhead sized thing on the side, not in the core area. Already took it to the radiator shop. $20 was the estimate. Think I'll just continue on the 'custom fitted' shroud idea. Looked like it would have worked if I had secured it better. I layed down a swath to cover that area between the radiator ledge and the front of the engine. Upon rapid acceleration, this swath caught the wind and blew back into the fan. Woops. I'll get it right one of these times.
     
  6. LKJR

    LKJR 1/2 ton status

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    try getting some thin sheetmetal and screw it on there, you can bend it to stay and it will flex pretty easy

    Like em big and topless
    Excuse me...Would you mind removing your import from under my chevy?
     

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