Rep Power: 0

I have a 2004 Honda Civic and it keeps overheating I have checked the fans and they come on and off when they should I have changed the thermostat and while driving it when the heat didn’t work it overheats but all of a sudden the heat will start working and the car will return to a normal temp dose anybody have any ideas?

 
Rep Power: 511

first, burp the crap out of your coolant system. Breaking apart the system, you're going to introduce air, which is not conducive to engine cooling. Park at an incline (or jack the front end up if that's not possible), pop your rad cap off, start the car with the heater full blast. Continuously top off coolant until you can't anymore, then let it run for another 5-10 minutes, topping off as necessary. While you're waiting, make sure your overflow is between the min and max lines.

Second, check for coolant residue (evidence of leaks) anywhere. If it looks like a splatter pattern from the overflow tank, prepare for bad news.

Lastly, could possibly be head gasket leakage. If you're burping your coolant system and bubbles never stop, that's no bueno (cylinder to coolant leak). If your oil looks like a latte, that's a pretty tell-tale sign, too (coolant to oil leak). Active steam from somewhere it's not supposed to be (with the car running at normal operating temp), also bad news (water jacket to ambient leak). These D17's are notorious head gasket eaters, only reason I'm bringing all this up. Start with the cheapest/free-est checks first (listed above) and work your way down.

Honestly, from what you said in your post, sounds like you have a fatty air bubble in the coolant system. Makes sense if you didn't burp it properly post-thermostat change.