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Running Hot???

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 1990SilveradoK5, Jun 18, 2001.

  1. 1990SilveradoK5

    1990SilveradoK5 1/2 ton status

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    OK took the Blazer on its first road trip since I purchased it in January. 4 people gear and two canoes on top and it was running hot, w/ no air. It was warm 75-85 and the Blazer got up to 255-260 while driving 70-75 MPH.

    I changed the thermostat prior to heading back south yesterday morning however the trip back saw the same result.

    What would be my next step?
    I was thinking I would want to flush the system prior to doing anything but do our Blazers have a common cooling challenge/problem?

    Gone Large and Loving It.
    Keith
     
  2. fr8train

    fr8train 1/2 ton status

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    Flush your radiator out and replace the cap. BTW what temp. thermo. are you running? Mine never had a heating problem that saw that kind of temps. On the off chance it could be anything else. Are the fins on the radiator damaged? Or clogged up or were they being blocked by anything? Have you checked your fan clutch? Has the transmission been looked at? What about your engine, low pressure on the oil or anyhting of that nature?
     
  3. WakeBoard&4X4er

    WakeBoard&4X4er 1/2 ton status

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    I had (and still might) the same prob. When i was running my truck in the hotter summer time my 1991 K5 would get real hot also. Since then i have flushed the block, new radiator, new cap, new thermostat, cut off cat, new O2 sensor. I have run it on the hi-way since and it never got that hot (in the 180 to 195 range), but it was not that hot. On thing you might what to look at is do you have a auto? If you do and you have 33 and 3.08 gears you are most likly killing your tranny. if you on the hi-way and you are running with a load like that my guess is that your tranny is sliding like a puck on ice.
    What I would do (and plainning on doing), put new gears in your diffs ( w/ auto i would do 4.11 or 4.56) that would give your tranny some help with the weight. Flush your block and put a new cap on the radiator (cost you about 20 bucks). GET A TRANY COOLER!!!!!!!! the the only other thing that you might want to do is get a temp gauge for the tranny so you can see if it is getting hot also.
    hope it helps
    brett
     
  4. 1990SilveradoK5

    1990SilveradoK5 1/2 ton status

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    Yes, I did just put the bigger tires on and it was the first long trip at any speed since.

    I will be flushing my block and cleaning up the radiator. It does have a tranny cooler below the radiator, however I might remount it as it is now laying down. I will remount it infront of the radiator so it catches more air.

    What gear swap would make my trany run like when I had my stock tires?

    Gone Large and Loving It.
    Keith
     
  5. GRINCH

    GRINCH 1/2 ton status

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    Are you sure it's the tranny cooler under the radiator on the frame. I have a factory towing package and it's a cooler for the power steering. I have a factory ext. oil cooler on the right side. I put mine on the left.

    The Few, The Proud, The K5 Blazer
     
  6. Triaged

    Triaged 1/2 ton status

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    My friend had the same problem (running hot on freeway but not around town) with his 90 Izuzu Pooper. He tried alot of different things (oil cooler, lower temp thermistat, water wetter, flushing) and none of it worked. Than he had a larger core put into the radiator (being a Forin' 4banger no larger one could be found) and it cured the problem. Now he can drive 80 with the a/c on in 90+ deg weather.

    '71 Blazer CST with alot of rust
     
  7. 1990SilveradoK5

    1990SilveradoK5 1/2 ton status

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    Well if I trace the lines that they spliced into it goes from the transmission to the radiator where the standard cooler line goes.
    I had originally thought it was an oil cooler also, but traced the lines and trany cooler it was. Also it does not have any cooler lines comeing from the oil filter area.

    Gone Large and Loving It.
    Keith
     
  8. Blazer1970

    Blazer1970 1/2 ton status

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    Take your radiator to a radiator shop and have them flow check it. It only costs a few bucks, and will save you from draining the system again. If it is partially plugged, you can't tell yourself. They will either be able to clean it out (they pull the tanks off and rod it out), or they will re-core it if it is plugged. The radiator is most likely your problem.

    Tim

    70 Blazer CST 4X4 350 SM465 NP205
    87 Burb 4X4 350
    01 GMC 2500HD 4X4 Duramax/Allison
     
  9. WakeBoard&4X4er

    WakeBoard&4X4er 1/2 ton status

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    i have the same set-up that you have and i think that i am going to fun some 4.56 or 4.10s when i get the money. Mostly is beacuse i might go to 35 or 36 some day
     
  10. 1990SilveradoK5

    1990SilveradoK5 1/2 ton status

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    I called the shop down the road and they will sell me a recored radiator for $188 with exchange.

    Is this the going rate?

    Gone Large and Loving It.
    Keith<P ID="edit"><FONT SIZE=-1>Edited by 1990SilveradoK5 on 06/19/01 02:44 PM (server time).</FONT></P>
     
  11. WakeBoard&4X4er

    WakeBoard&4X4er 1/2 ton status

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    well i pulled mine and bought a new on for $140 if you have about 3 tools and about 1 hr you can do ityour self.
     
  12. Cavalry

    Cavalry 1/2 ton status

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    I purchaced a brand new rad with lifetime warranty for $190 at a local shop

    "There is a fine line between hobby and mental illness"
    Luke
    84 K5
     
  13. realsquash

    realsquash 1/2 ton status

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    MAke sure you've got a complete fan shroud and at least a 180 degree thermostat (195 is optimal).

    Squash
    <A target="_blank" HREF=http://www.trailrunners4x4.org/users/realsquash>http://www.trailrunners4x4.org/users/realsquash</A>
     
  14. 1990SilveradoK5

    1990SilveradoK5 1/2 ton status

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    Just put in a new 195 degree thermostate and the fan shroud is all present.

    I think the radiator is the first thing I will be changing. As when I tried to drain off some fluid the petcock was open and nothing came out. That leads me to believe that it has quite a bit of sludge in it.

    Gone Large and Loving It.
    Keith
     

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