hey people i need some help. i have a question i tried to change my thermostat and after removing the old 1 and putting the new 1 filled the radiator the RPM start to go up and down up and down the bottom radiator hose seems cold no pressure not sure i left the car on and radiator cap off for 10 to 15 mins water start to come out steaming plz help me i dunt know what i did wrong soo plz help

thanks in advance

 

Sounds like air is still in the system, and needs to be bled out. Thermostat also sounds like it hasn't opened yet.

Here is a link to bleeding instructions:

https://honda-tech.com/zerothread?id=1169497