I'm sorry if I didn't post this in the correct place, I lurked around and tried to figure out where to post.
My 97 Accord only has 64,000 miles and was owned by a little old lady who only drove it to and from church. When I bought the car my mechanic said everything was fine and we replaced the thermostat and timing belt for good measure (the timining belt hadn't been replaced since the car was first bought.)
after driving all day yesterday, I stopped at the grocery store and noticed a strange humming that sounded like a fan coming from under the hood. The car was off and key out of the ignition.
I noted it and decided to see if the sound had stopped when I came back out. It had so I drove it home.
once I arrived I noticed my temperature gauge was all the way at hot and some steam/smoke? was coming from the hood. I turned the car off. The humming continued, then stopped, then kicked on again after 5 minutes, and turned off. I waited an hour, (for someone who knew better than I did, to come look) once we looked under the hood it literally looks like the antifreeze exploded from under the radiator cap. We put more antifreeze in (about half a gallon) and started the car and watched the temp gauge. I let it run for a solid half hour and the temp gauge remained fine, I even drove it around a bit to try and get the fans to kick on but they never did. I played with my heat, watched the antifreeze (it looked like it was swirling around, but other than that little movement, and looked for leaks but saw none.
Im at a loss because my knowledge only goes so far, and was hoping someone could give me ideas.

 

The buzzing noise was the radiator fan running due to the heat of the coolant.

When you idle the car and let it get to operating temperature while watching the gauge, you should also check both the top and bottom radiator hoses. If they both get hot, that verifies the thermostat you just put in is operating correctly.

If you don't see any cracks in the neck of the radiator, then your cap could have failed.

You can have the cap pressure tested, it is likely it can't hold the pressure.

The other concern is if you hit the red line on your temp gauge, that is typically when it warps the head. Hopefully you managed to catch it before that happened.

When you did the new timing belt, you should always replace the water pump with an OEM one (better fins and water circulation than most aftermarket pumps).

Idling the car with the cap off for 30 minutes is the basic premise of purging the air from the system. You need to do it with the heat selector to max hot. No need to turn the heater fan on, but you do need to set your heater to max hot.

Then you idle the car with the cap off (so you can top it up as you go) until the fan kicks on at least twice. Feel both hoses and they should be hot and your temp needle should never pass half way.

This is now a purged system and you can shut the car off, top up the radiator to the filler neck and put a new cap on. Then fill your reservoir to the max line while the engine is hot.

Then drive the car normally and keep your eye on the gauge for a couple of days to verify stability.

The only portion I don't know is if your accord has a bleeder screw. Some of the older honda's have it and some don't. It doesn't change too much if you do and if you can park the car with the noise raised a little higher than the rest of the car, the method I explained will still purge the air regardless if you have the bleeder screw or not.

Hope you find this information helpful.