I replaced a timing belt, water pump, and thermostat recently. I drove it for the first time since and I heard gurgling. It dawned on me that I forgot to burp the coolant system. I drove it a few more times with no overheating issues and finally got around to burping it. I rigged up a funnel in the radiator, started the car, and started adding coolant. It took a few cups of coolant, then looked as though it was full, so put a bit more coolant in the funnel and let the car idle for about 5 minutes. It burped once or twice, but that's it. I let it continue to idle. I was expecting the fan to come on at some point, but it never did. This perplexed me a bit because the fan worked prior to and after installing all the new parts. The upper and lower radiator hoses were warm/hot to the touch. No more air bubbles showed up even after 10 more minutes of idling. At this point the coolant started to boil. I put the radiator cap on and shut the engine off.
I wouldn't think it's a thermostat issue since both hoses were hot. I suppose it could be the water pump maybe, but it's a brand new Aisin pump. Still not sure why the fans didn't kick in. Any ideas would be appreciated.