2003 overheats at idle even with fans running, ok if AC ia on at idle

by Guest8840  |  12 years, 10 month(s) ago

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After experimenting n the driveway with my 2003 Corvette, I found what appears to be insufficient (if any) coolant flow out of the engine below 850rpm. The heater does not blow out hot air either. If I push the rpms above 850, the temp comes down. The fans do kick in about 232degrees but have no effect without the higher rpms. One odd item, if the AC is on and rpms are below 850, no problem. The fans kick in and the temp goes down.




  1. Guest6436
    I figured it out.  In the process of replacing the thermostat with a 160 degree unit, draining and refilling the cooling system, I discovered a large air bubble in the cooling system.  I put more coolant in than what drained out!  While I was cycling the engine to 230 degrees, then slowly opening the coolant fill cap, I noticed bubles working their way up to the overflow canister.  After the third cycle of heating up, then cooling down, a large woosh sound and the coolant level dropped.  Now the engine finds a happy medium around 198 degrees and varies only a couple of degrees, even in 90+ degree wheather!  Dennis

  2. Guest840
    This could be several things, it could mean that your Thermostat was installed upside down, or your radiator is plugged up. Also it could mean that your computer is just opening the thermostat late. The only way to really find out would be to have somebody hook it up to a scan tool. They need to watch the heat rate it should increase to 160 or 198 (depending on what degree thermostat you have in your vehicle) then you should see it decrease in heat then pick up again to around 221 where the fans will then kick on to then cool the engine down. If it passes the thermostat and doesnt decrease then that means a bad thermostat. If it keeps increasing at 221 then that means that you could have a bad fan relay or the computer is just not finding the right spot to turn them on.
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Latest activity: 14 years, 6 month(s) ago.
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