2001 honda civic ex 206,000 miles. Overheating. Changed water pump, flushed radiator, changed thermostat, tested fan (good), pressure tested engine (good). Replaced fan sensor connection. Had sit for 30 minutes at a shop running but didnt overheat. Drive for about 20 minutes and stop at a light and it begins to overheat. Once moving the temp goes down. All repairs and tests were done at a Honda dealership . 1500 bucks later(got a new timimg belt since the pump was off) and still the same problem.

SOURCE: location of air filter honda civic 2000

http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c1528018f440

SOURCE: overheating from leak not visible

Hook up a cooling system pressure tester. If you have a pin point leak, the pressure from the tester will shoot coolant out of the leaking area.

SOURCE: Have a 2002 Honda Civic HX that when idling the heat stops

I would check o2 sensors but to tell you the truth my dad bought a new thermostat that was suppose to open at 160 degrees his temp. got to 220 degrees before but check o2 senors and thermostat

SOURCE: What could make my 03 civic ex overheat and cool

your heater has apparently restricted the coolant flow....hopefully a good system back flushing will cure the problem....use a flush obtained from a parts house....I would buy the hose kit for flushing as well...good luck to you

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SOURCE: 2003 Honda Civic LX 90k miles replaced

it is possible that when the water pressure rises in your radiator, and the radiator shoots the water into the reserve tank, that hose is not properly put on(happens alot when changing radiator) and the coolant leaks rapidly through there. another thing i suggest is observe your fan behavior. fans usually are only supposed to turn on for a couple of seconds, around 10 or 15. park your car, and let the car reach normal operating temperature. when the car starts to over heat, check to see if your fans turn off at all. if they do, then it is most likely the tw swith,or the water temperature switch. if you notice the fans stay running, then i suggest obesrving your hoses and replaing any that spill coolant because even a pressure test on your cooling system can miss a small pucture in a hose, which after a while will cause your coolant to leak, and your car to overheat. hope this helps. if still nothing, drop a comment and ill help you out somemore, but for now, this is the practical thing to do. hope this helps, goodluck.