EGsex

my heater recently doesnt work not sure why, put it on all the way on the red and i cranked it up and blows cold air ...and then few mins later i got in the highway and my temp went over the normal temp so i pulled over to check if im short in antifreeze or if i had a leak, that wasnt it...so i drove again and it did it again and i tried the heater thing again and it still blows cold air and checked if im leakn anti freeze or my radiotor is busted but none of them....i dont even see any smoke comin out of anywhere in the engine bay.....what could it be??...really pisses me off......

Hondaaccordvtec

After the car has run for a while, put your hand on the top coolant hose - Is it warm? if not, most likely what you suspected - a bad thermostat.