1999 Sierra 1500 Overheating

jaredrappjaredrapp Member Posts: 1
edited June 2017 in GMC
To my knowledge: approx 5 years ago the WP, Rad, and t stat was changed. Operated fine since then until about 6 months ago. Noticing the truck running hotter. Losing coolant. And what seemed like very small chunks of rubber in the coolant. Started over heating on me.... So, Just flushed and replaced the T stat the WP. Still overheating. My question is. How probable is it that the Rad has gotten clogged with what I'm guessing is the remnants of the old WP.. and how to i remedy it. engine gets hot. Top hose on rad gets hot. Bottom hose doesnt. Opening the drain on the Rad while engine is hot. Cold water drains out.


  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Well if you are losing coolant, that's your first step. Where is this coolant going? You might want to do a pressure test to find the leak.

    If the coolant lose is through the overflow tank (boiling off) then you have a quite serious overheat issue. Certainly if you have debris in the coolant, then it is clogging up the radiator.

    It's hard to know which is your cause and which is your symptom here but if you have no circulation through the radiator, after checking for a leak, then the radiator has to come out and be flow-tested.
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