Cheapshot

I own a 98 civic ex D16Y8 that has over 233 thousand miles on it. The other day I had to replace the radiator and thermostat. After replacing them, I started the purge of the cooling system but the thermostat never seemed to open, the motor never overheated, radiator fan never turned on. I know I have the correct thermostat and gasket for it. The motor took forever to come up to temperature, heater blows good hot air though. Anyone else experience this? Seems weird to me but as long as it continues to run good I'm not going to mess with it.

ezone

Leave the heater fan off. If you left it running on full heat while trying to warm up the engine, that could nearly double the time it takes to get up to temperature.

Idling places no serious load on the engine. Therefore not much heat is produced.
Drive it to get it warmed up faster.
"You have to burn X amount of fuel to get 2 gallons of water hot. You can do that fast or slow. Your choice."

If it is cool where you are, and the wind is blowing a little, that might remove enough heat from the radiator that the fan is not needed.

Old but good

I agree. It always seems to take a lot longer than I expect for the thermostat to open and the fan to come on when purging the system, but it usually does come on eventually. Driving it will help heat it up faster.

Mishimoto

If you are not overheating and the vehicle did eventually read operating temperature I would say you are good to go. Having the heater on is necessary for purging the system. I would guess once you get the car on the road it will warm up at a more reasonable pace.

ezone

Heater: **** set to max heat so the valve is open and water can flow, but leave the fan turned off.