Steve,Popular 365 Question

Having overheating issues when stopped in traffic or drive-thru for 8 minutes or more in 85+ degree Texas weather. Once I start driving again or increase the RPM's to 1,000 or more the temp. goes down. During normal driving there are no issues with overheating even in 100 degree weather. I hear more fan...

9 months ago 3


  1. efflandt

    How hot is hot. A 2008 GMC 2500 work truck I used always ran at 210 degrees F from the time it was new. The boiling point of 50/50 coolant/water with 15 psi radiator cap is about 240 degrees F (or at least that is what I figured some years ago when the hot light came on in a car, I installed a temperature gauge and discovered it was running at 230 due to a plugged radiator from stop leak that I tried to use for a leaking heater core, had to get radiator recored).

  2. Benjamin

    Me and a friend have GM-3800 engines and have had this same issue lately. The engine gets hot and overheats a little in traffic until you turn the cabin heat all the way up. The fix for us turned out to be a new water pump. Stock GM water pumps use 3/4" turbine blades and lose their bearing clearances after billions of rotations. Quality aftermarket ones often come with 1.5" or larger turbine blades that move more coolant.
    It could also be a clogged radiator, bent radiator fins, gunked up thermostat housing.

  3. Penn Stater

    Check the thermostat. It is probably the culprit. When you are driving, your engine is cooled through convection from the moving air. With elevated engine rpm, your mechanical fan will spin faster, increasing your air flow. At idle, your cooling system has to displace more of the thermal energy. If the thermostat doesnt open correctly, it wont let the coolant to flow properly through the ports in the block and can lead to overheating.

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