bad thermostat symptoms?

[silver8thcivicr18]

could a faulty thermostat cause both radiator fans not to engage?

[The Power of Dreams]

One is a condenser fan. One is a radiator fan.

With the AC on, do any of the fans operate? Both should.

[silver8thcivicr18]

yes both of them come on

[habitat]

In my experience, the thermostat is purely mechanical. It functions to restrain the liquid coolant to your engine when the coolant is cold (like in the mornings) to heat up the coolant to operating temperature quicker. After a certain temperature it automatically opens to allow full circulation though your heater core. That is why it takes a few minutes for your heat to come on during cold mornings. Your fan should come on when the coolant is too hot. If your thermostat is stuck in the blocked position, it could overheat quicker, it will also completely disable your heater from working. So, start up your car and when it warms up, check if the heater works, if the answer is no, you may well have a broken thermostat.

[The Power of Dreams]

Originally Posted by habitat

In my experience, the thermostat is purely mechanical. It functions to restrain the liquid coolant to your engine when the coolant is cold (like in the mornings) to heat up the coolant to operating temperature quicker. After a certain temperature it automatically opens to allow full circulation though your heater core. That is why it takes a few minutes for your heat to come on during cold mornings. Your fan should come on when the coolant is too hot. If your thermostat is stuck in the blocked position, it could overheat quicker, it will also completely disable your heater from working. So, start up your car and when it warms up, check if the heater works, if the answer is no, you may well have a broken thermostat.

When the thermostat opens, it allows full circulation to the radiator, not the heater core. It takes a while for heat to be produced by the heater core because the coolant is still relatively cold and has not been heated sufficiently by the engine.

Restriction of coolant through the heater core is a function of the heater valve. Some Hondas have one; others do not. With those that do not, the air mix control door is used to allow heated air into the cabin, or to preclude its entrance, depending on the driver's desire.

[habitat]

Originally Posted by The Power of Dreams

When the thermostat opens, it allows full circulation to the radiator, not the heater core. It takes a while for heat to be produced by the heater core because the coolant is still relatively cold and has not been heated sufficiently by the engine.

Restriction of coolant through the heater core is a function of the heater valve. Some Hondas have one; others do not. With those that do not, the air mix control door is used to allow heated air into the cabin, or to preclude its entrance, depending on the driver's desire.

Ah yes that also makes sense, well same concept i suppose. If the thermostat is in an always on position, it would always pass through the radiator causing your morning startup(and heater) to take longer than normal, correct?

[The Power of Dreams]

Originally Posted by habitat

Ah yes that also makes sense, well same concept i suppose. If the thermostat is in an always on [open] position, it would always pass through the radiator causing your morning startup(and heater) to take longer than normal, correct?

Yup, yup.