Hi I h s40 2.4i auto, radiator fan isn't working, I changed thermostat n replace with new 1 but still gauge raise over temp n still doesn't kick in, I ran the fan directly it runs perfectly, pls help

SOURCE: Radiator fan not working

Hi,

I am assuming that you are referring to the radiator fan. You need to verify that the fan motor is receiving 12V when it is supposed to be kicking in (engine hot) with a DVM (voltmeter) in its actual location. Having done this and likewise verifying that the ground is properly attached/connected, then your problem would be with the "clutch". Radiator fan clutch differs from aircon compressor clutch which is electrical and the transmission clutch which is mechanical. Most radiator auxiliary fans (not directly coupled) uses "silica oil". This oil has an inverse property, that is when hot it gets thicker and thus the rotation of the motor is transferred to the blades. There would be a filling hole adequately plug in or near the front of the fan assembly.

If your concern is not corrected by the addition of silica oil or if you can not measure 12V on the fan connector itself when it is supposed to kick in, then chances are your problem is electrically related. Some fan motor switching systems are coupled to the aircon switching.

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards.

Thank you for using FixYa.

SOURCE: Radiator fan not working

Hi. Check the bottom of the radiator or on the side, as you also have a temperature-sending switch. The switch must reach a certain temperature before sending a signal on to the fan relay.

The switch just screws into the radiator.

If you would like to contact me again about this or other problems, feel free to do so.
Bill
ASE Master Technician

SOURCE: running hot

Radiator Fan Control Relay Switch. I bet your electric fan doesn't run?

Steve Allison

• 5569 Answers
• Posted on May 26, 2009

SOURCE: radiator fan not working replaced relay,temp

You didn’t mention replacing the temperature sensor located on the block in the path of the ‘cooled’ coolant.
I can’t tell you any closer where to look for it since you didn’t specify which engine you have.
This device is a solid state item called a thermistor.
With the air temperature around 77 degrees F and a 'cold' engine, it should measure about 10,000 Ohms and hot, around 1,200 Ohms while disconnected from its mating connector.
With the ignition on, and the connector disconnected from the sensor, you should measure about 5 volts coming from the ECU.
If this has failed, the ECU is not getting the right info back from the sensor and doesn’t know if the fan is needed or not.
 

SOURCE: 1997 honda civic over temp. Have replaced

Generally if one hose is hot, and the other hose is cold it indicates that they water is not circulating. You could have a defective thermostat. Take the thermostat out and run the engine without it. With the radiator cap off you should see a lot of water moving through. It that is the case, replace the thermostat and you should be ok. If there is no rapid movement of water it may be the impeller on the water pump came loose. This is rare, but it can happen since the impeller is usually pressed on the shaft. You should also check and see if you get a lot of bubbles when the car is running and the cap off. This often indicates a blown head gasket. Hope this helps.