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  1. #1
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    Default Can't get my 305 over 150 degrees Any help would be apprecieated!!!!

    I already tried------ 3new t-stats--changing hoses--bypassing the heater---running with out the fan --closing off the rad. and changing the heater hose from the rad. conection to the old style water pump connection. NOTHING HELPS !!!!!

  2. #2

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    Are you sure your gauge is reading right?
    It's very rare for an internal combustion engine to run to cool.

  3. #3

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    I think you changed everything but the gauge, try a water temp meter and see if the gauge is correct.
    Ray

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

  4. #4
    Legend

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    Default

    could be the thermostat is the wrong one allowing coolant to bypass it. I would hook up all the coolant system as built OEM and when removal of the thermostat make sure that it is properly seated into the bore so that no coolant can go around it. should be a 195 deg f thermostat on temp. all thermostats should be tested before installing I found many NEW defective ones. could be on this 305 you need a rubber gasket on the outer circumference of the thermostat.

  5. #5
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    Quote Originally Posted by tbplus10 View Post
    Are you sure your gauge is reading right?
    It's very rare for an internal combustion engine to run to cool.
    Yes The dash gauge is correct I also used a rad. thermometer
    and they both match.
    All the thermostats came with a rubber gasket and I tested all of them in a pan of water on the stove with my rad thermometer
    in the water.

  6. #6

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    Quote Originally Posted by Erby View Post
    I already tried------ 3new t-stats--changing hoses--bypassing the heater---running with out the fan --closing off the rad. and changing the heater hose from the rad. conection to the old style water pump connection. NOTHING HELPS !!!!!
    Are you using "failsafe" thermostats? Everytime I have used one of them I have had the same issues

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors, http://www.gmtruckclub.com/forum/sho...5-GMC-Yukon-XL
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  7. #7

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    Quote Originally Posted by Pikey View Post
    Are you using "failsafe" thermostats? Everytime I have used one of them I have had the same issues
    I agree with Pikey. I didn't realize until I was on my 2nd thermostat. To the tell the difference, you will NOT see any part on the spring. To check for sure...and to check the one you have in the truck, use this test. Get a small cooking soup pot and add 3 cups of water and boil to 190* while the thermostat is in the water. Remember to keep the automotive thermometer in the water and check the temp. as it temp rises and the water boils, watch to see when it opens. It should open at 190*. if it opens sooner, go replace it. As soon as you take it out, it should close.

    A failsafe will open at or around 150*. With winter coming, you not be able to defrost the windshield.

  8. #8
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    Default

    I put Gates T-stats in, none of them were marked "failsafe" , do I have to request standard ? Keep the suggestions comming everyone.

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