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2009 Chevy Silverado 1500 overheating issues–Please help!

Home Forums Stay Dirty Lounge Service and Repair Questions Answered Here 2009 Chevy Silverado 1500 overheating issues–Please help!

This topic contains 3 replies, has 2 voices, and was last updated by Nightflyr * Richard Kirshy 4 months ago.

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  • #963645

    So I have the 2009 Chevy Silverado 1500 5.3L. Its at 178,000 miles. I started having some coolant leaks, ended up getting all new hoses, new radiator, thermostat, water pump. Ran okay for a little bit, then started overheating again. Kept getting air in the system (mechanic said he saw no signs of a blown head gaske), I used the Blue Devil engine block sealer (was getting some white smoke at cold startup too, maybe unrelated). Air stopped getting in the system and the truck ran great for a couple weeks. The over heating came back, but no air in the system. It just runs really hot (normal is 210, its running about 230-240 with heat on full blast).

    The overheating comes with higher speeds, 30 mph and above, then when idling it goes back down. Sounded like a clogged radiator to me (from the blue devil) I flushed it and put a new thermostat in, but still same problems. Also there seems to be a lot of pressure in the hoses. I can actually hear a very small hiss coming from the coolant reservoir cap. I am just stumped, any advise would be greatly appreciated!

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  • #963650
    Nightflyr *
    Richard Kirshy

    To start with, using any type of “repair in a can” in most cases only cases more greif later on.
    No doubt the sealer has caused issue(s).
    From what your describing, I would venture a guess that you may have a blockage with in the engine itself.
    Hind sight is always 20/20.
    After you replaced most of the cooling components ,you should have done a chemical coolant system flush.
    My suggestion would be to remove the thermostat, then first flush the system with a good detergent to remove as much of the sealant as possible.
    You may need to perform this type of flush several times.
    Then use a proper cooling system chemical flush according to the instructions.


    Thanks Richard, to do a proper flush, would you just put the lower hose back on without the thermostat, then run water thru the top hose? I was also wondering how much water should “flow” through the radiator with the hose. The hose I’ve been using has great water pressure, but it doesnt flow through the radiator fast enough, it seems somewhat weak coming through the lower hose. Either way, I guess it just needs to be flushed out like crazy

    Nightflyr *
    Richard Kirshy

    Ummm no …
    Pull the stat, all hoses connect as usual.
    Fill the system with soap and water, run till to operating temp is reached, let run for several minutes.
    Let it cool down, rinse and repeat as necessary.
    Then flush using a chemical flushing agent as directed
    Might invest in a PRESTONE flush kit:
    Install the flushing TEE as directed makes life so much easier.
    Remember to use distilled water.

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