Hi. I have noticecd in the past week or so that after my honda 96 civic gets to running temperature, the overflow reservoir bottle starts boiling and bubbling. this then drains the bottle completely. i need to know asap as to how this can be sorted as i need the car for daily use. thanks.

Change thermostat first! Then change temperature sender!

Its normal for the car to have antifreeze going to the overflow tank if thats what your asking.

If the thermostat is not opening, the engine will keep getting hotter as you drive. You could be low on coolant and have air pockets in the system which would cause the temp gauge to not be accurate. Is the radiator fan coming on when the tank is boiling ?

Water expands with heat if you completely topped up the reservoir cold it should overflow. Actually the biggest problem is when breathers block on reservoir caps and the water vapour pressure cracks the bottle. The reservoir allows you cooling system to run full and take in account the volume (expansion ) increase when engine gets to running temperature.

I just today actually fixed a similar problem in my honda my problem turned out to be the Timing belt was loose and not gripping to turn the water pump causing all sorts of problems with the cars temp. and water temp. including the fan not coming on, it sounds dumb but it worked for me just push on the belt and if it moves its loose. quick turn of a wrench and fixed.. Good Luck

Not sure what the problem is, there is no question here only a statement. Are the fans running?

I'm NOT a mechanic.. But.. Check this by starting engine with radiator cap removed, and look for flow.
Do you see a lot of bubbles? Esp when engine is still cool.. And bubbles are full of vapor? My guess is head gasket leak.. Blowing exhaust into the coolant. Gas in coolant preventing proper flow, and overheating the coolant, and simultaneously over pressurizing cooling system, causing blow out.

Are you seeing any steamy exhaust. ? Try pulling plugs and looking for extra clean one.
Good luck..

You have a faulty Temperature sensor and need to replace the Thermostat.

You would need to check out the different cooling components. The radiator cap, thermostat, fan for radiator (car should run at 195 degrees), is anything blocking the face of the radiator, are any of the cooling hoses kinked or collapsed, is the water pump circulating the coolant, is thw belt still on the water pump?

It could be, take the thermostat and boil it in a pot of water, if it don't open, it's a bad thermostat.