Is it okay for my radiator fan to run full time.?

Question

Hi,
I recently replaced the radiator on my 1993 Toyota Celica. The new radiator didn't fit the Coolant Temp. Sensor which is used to start and stop fan. I left it out for now. Without this sensor the radiator fan always runs. Apart from taking a little longer to warm up and maybe decreased millage is there any downside to this?
The car has had overheating problems in past (Hence radiator replacement) so keeping fan on wouldn't be a bad thing.

Thanks.

Answer 1

The engine will still come up to temp as that's controlled by the thermostat on the front of the motor. When the engine is cold very little coolant flows through the radiator anyway.

As the engine warms up the thermostat opens and lets coolant though the radiator.

Now if you are driving along there is enough air though the radiator so the fan isn't needed.

But if you are driving slow in traffic, or stopped, there isn't enough air flow to cool the radiator, so the fan turns on.



So, 99% of the time the fan may not even be needed. Now having it running all the time isn't a disaster, older cars have a fan belt and the fan just spins all the time. This wastes a bit of power, so newer vehicles have gone to a thermostatic fan, that only starts up when the water coming out of the radiator is warmer than it should be.



Main risk? The fan motor will burn out sooner because it's running more than it should.



I would suggest you try and rig up some way of getting the sensor connected back into the system.



Car is still OK to drive in the mean time though.

Answer 2

Your thermostat should keep your engine hot, allowing water to pass only when temp is right, but the electric fan will run always. This will cost a little in electricity, making the alternator run more, but I don't think it will affect mileage that much. Fans on older cars ran all the time, with belts. Later they had fan clutches that allowed the fans to slow down, when engine is cool. The cost was belt run fans, so it did take a little power to run, and gas mileage, but again, very insignificant.



As someone said, engines are designed to run at a set temp, but with the thermostat controlling water into the radiator, the engine should remain hot anyway. While the hot water flow is cut off to the radiator, the fan is not cooling anything down, so it is wasted energy, basically.



You might look on Auto parts stores online, and see if there is any type of heat sensor you can add to start and stop the fan. I think after market electric fan kits, have some sort of attachment.

Answer 3

Your engine needs to reach the proper operating temperature as quickly as possible so the computer can enter closed loop which means that it will then be monitoring and responding to all sensors for optimum fuel mileage and performance. Colder running engines are also prone to allowing oil sludge to build up and your heater and defroster will not work as efficiently along with a bigger drain on your charging system. So although not a bad thing it's not such a good thing either. If you plan on keeping the car get the correct radiator.

Answer 4

buy a used sensor a wrecking yard - why burn out the motor on the fan, & the other components need this working so they can function as well.

Answer 5

No. It's not ok.

You need the sensor to be installed and operating properly.

Answer 6

Worst cases it will shorten the life of the fan motor might burn up the relay.

Answer 7

faster wear of the fan but no problem. Maybe you can rig up an adapter to make it work when you have time.