i just bought a 98 civic dx the first day i went to drive it ran fine till i floored the car i got up to about 65 as i let off i noticed the temp rising so i shut the car off and looked under the hood i noticed the res. tank was fool and the anitfreeze had been pissing out of the cap. the radiator was empty. i left the car there over night when i came back i poored the antifreeze from the res. tank back into the radiator . and drove off i never had any overheating problem again. but i did notice that my reserve allways full past max and my radiator is allways empty . in the mornings after the cars been sitting i open radiator it has air presser in it . the car runs good i never tryed to gun it again thoe . i changed the radiator cap but that nothing changed..ac works fine a/t 112xxx miles. when i start the car sometimes rpms will b high for about ten seconds and then just drop and then slowly increase and so on . its not a big rmp change. does need a tune up thoe bad. please help email me dfernandez136@yahoo.com

 

Likely a slow leak in the head gasket. Get the cooling system completely full. Engine COLD, take the radiator cap off and start the engine with the cap off. Rev it up and see if there are any bubbles in the radiator.

 

try to change your thermostat and then check your hoses and make sure they are good and not leaking