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HELP, 350 cooling problem

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 77k5, Oct 17, 2000.

  1. 77k5

    77k5 Registered Member

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    I have a 350 that has been bored to a 355, has flat top pistons, a GM high output cam, Holly street dominator intake and an eldebrok carb. The engine has about 2,000 miles on it, and it would start getting hot if I stoped at a red light or if it would just sit and Idle. I have put a new 3 core radiator, a new water pump, a new heater core and I'm running a 160 therm. I have gotten it where the temp will not just keep climbing. Now what it does if you drive up a hill it will go from 180 to 195 and when you go down the hill it will go to 180 or 170 sometimes, but the temp. will not regulate and stay at the same temp. I have tried a 16 inch electric fan and that hasn't helped either, I'm baffled. Thanks for reading
     
  2. Sparky

    Sparky 1/2 ton status

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    Not real sure what to say. I would have suggested changeing the fan clutch, but the electric fan should have taken care of that. Why not run the OEM thermostat? (190) It might be eaiser for it to keep at a constant temp. They are not expensive so why not try that? What about the thermostat you have now. Are you sure it is working properly? Good luck!

    Sparky

    78 K-5
     
  3. BigBurban

    BigBurban 1/2 ton status

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    Try the 195 stat. What happens with 160s in alot of cases is that once the thermostat opens it never closes again and in turn the radiator doesn't end up holding onto the coolant/water long enough to disperse the heat. Check your coolant/water mix... A change of just 10% can make a big difference. Are you running a regualr fan along with the electric 16 inch? If so, are you still using the shroud? If not, a single 16 inch fan probably won't cool the truck since it's only pulling/pushing air across a 16 inch diameter area of the radiator. Have you checked the fan clutch? Some people out here in AZ just toss it in favor of a spacer. Hope this gave you some ideas. Good luck. [​IMG]

    <font color=red>~BigBurban</font color=red>
    http://www.geocities.com/crash607
     
  4. BUDDY

    BUDDY 1/2 ton status

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    I was having the same problem with my blazer and I didn't have the money to go through all of that cooling stuff, so, Ireset the timing and retarded it slightly to compensate for the altitude that I live at,(about 3,500 ASL), and that totally fixed it. I actually have better throttle response and fuel mileage to go along with not freaking out any time I saw a hill on the horizon. I'm not sure if I did it right, because I just did it by ear. But man it made a HUGE difference. If you want to do it right go get a timing light, (40.00 at Wal-mart), and set it to the specs recommended by a reputable engine builder in your area.

    Maybe this will help,

    Buddy

    I've got my dream truck and it's a 72 K-5 that is getting there!!
     
  5. 77k5

    77k5 Registered Member

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    I've been working on my 77 chyenne for about a year now, I started out not knowing anything at all about it, I've learned alot and I still have alot to learn, Thanx for all your reply's you all have helped alot.
     
  6. DMK

    DMK 1/2 ton status

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    Sounds like it could be an air flow problem. Did you use the electric with the stock fan? I once had an 69 442 when I first bought the car it did the exact same thing as yours.
    Found that someone put on an flex fan but it was on backwards, not too smart.
     
  7. rich'90

    rich'90 1/2 ton status

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    Chris, is that you? I met you the other day. Did you find out about that front axle yet? Any luck on the cooling problem?
    Give me a call or e-mail if you find abything out.
    Thanks, Rich

    Go heavy or Go home[​IMG]
     
  8. sosamantx

    sosamantx 1/2 ton status

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    <font color=blue>Are you sure that you don't have air in the system? Try taking off the radiator cap (NOT WHEN IT"S HOT), and letting the vehicle run till the thermostat opens up, you should see the water circulating, and fill it with fluid. Also, what shape is your radiator cap in? And, what pressure cap is it? I think it should be like 15 or 16 lbs., or something like that, if the cap isn't sealing (holding the pressure), it will cause it to run hot, or wrong pressure also. What about checking your timing, too much advance can make it run hot as well. Just my 2 cents worth. - Steve :)</font color=blue>

    <font color=blue>Steve Sosa a.k.a. "sosaman"</font color=blue>
    http://sosaman.home.texas.net/carpics.html
     

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