My honda is over heatin why

There are several reasons, and causes as to why this is happening. I'll start from the simple causes, then go to the more complicated ones.

1.Thermostat is bad.
Thermostat is stuck shut, or not opening enough.
Solution? Replace. Make sure you get the gasket, and O-ring if used.

2.Too much antifreeze to water ratio.
For best cooling of your engines cooling system, a ratio of 50 percent antifreeze, and 50 percent water should be used. This mixture is sold, but they also sell straight antifreeze. Some think, "Well, if 50 percent antifreeze is good, I'll just add more. This should be better!"

Wrong!

The properties of antifreeze break down. Recommendation is to at least flush, and replace the antifreeze mixture every 2 years. From my years of experience I recommend every year.

Antifreeze not only keeps the temperature down for your engine, it is also a lubricant for the water pump, and an anti-rust agent. If you want to see a radiator clog the cores up in a hurry, just neglect to change your antifreeze.

3.Radiator cores are clogged.
Fresh antifreeze hasn't been used each Year. Cooling system should be flushed yearly, and new antifreeze used.

4.Radiator cap is bad.
Radiator caps are made to hold a certain amount of pressure. (10 to 12 Lbs. is common) Once the mechanism inside the cap goes bad, the amount of pressure needed is not enough

5.Blown head gasket.
Combustion gases inside the engine are escaping into the coolant. Coolant becomes hotter, and cannot take away the heat from the engine. Engine becomes hotter, as does the coolant. Soon the engine overheats.

CHECK COOLANT.IF COOLANT TOO LOW IT WILL CAUSE OVERHEATING.IF COOLANT LEVEL IS GOOD.YOUR THERMOSTAT IS STICKING CLOSED.IF ALL IS WELL.YOUR RADIATOR IS CLOGGED UP NEED FLUSHING.ENGINE BLOCK WATER PASSAGES IS STOPPED UP.LEAKING HEAD GASKET WILL CAUSE OVERHEATING. USE A SCANNER TO CHECK TO MAKE SURE COOLANT FAN IS WORKING.AND COOLANT TEMPERATURE SENSOR IS WORKING.COOLANT TEMPERATURE SENSOR IS WHAT CAUSES THE COOLANT FAN TO TURN ON AT 190 TO 200 DEGREES.IF COOLANT FAN NOT WORKING.HOT WIRE IT USING JUMPER WIRE TO BATTERY. IF FAN RUNS YOU HAVE A BAD FUSE OR RELAY.IF NOT FAN MOTOR IS FAULTY.REPLACE IT.ALSO CHECK WATER PUMP IF YOU SEE SIGNS OF ANTIFREEZE LEAKING AROUND WATER PUMP.REPLACE IT.ALSO MAKE SURE YOU HAVE 50 % WATER AND 50 % ANTIFREEZE. IN COOLANT SYSTEM TOO MUCH WATER WILL CAUSE ENGINE TO OVER HEAT.ALL OF THOSE THINGS IS POSSIBLE CAUSES THAT WILL CAUSE YOUR CAR TO OVER HEAT.