how i came across this i don't know, but there is a thread on this site. this guy nailed what my car was doing to a T..but i don't know where it is now.....

i forget what mine said but the honda thermostate opens at a cooler degree than any autozone/parts america/napa..ect..ect......

mine started going bad 'oem themo' the car was running hot. but would cool down at idle....picked up a cheapy thermos ran fine for a morning then started running hot again. but not as bad. started thinking my fan was bad or what ever else. 'just had the water pump done thought my was bad. already flushed it and burped it....after 3 weeks of scratching my head...i REPLACE THE CHEAP THERMOS AND GET A HONDA OEM THERMOS......now honda did try telling my 44 bucks and i said no way and they gave it to me for 22bucks......but she runs good now....good luck