Question: electric radiator fan

[Antz81]

Hi guys. Was out driving the vette after 9 months off the road. I was doing mainly highway driving and the engine temp was getting up to about 260f, the coolant temp was staying at about 200f. When I got to where I was going I popped the hood expecting the electric fan to be running but it wasn't. From what I gather it should come on at 230f, but is that the engine oil temp or coolant temp? I would have thought it's engine oil temp. Am I right? If so I need a new thermostat. (Fan does run if thermostat is shorted)

 

[Midnight 99]

It sounds like a fan relay is out or the sensor is no good. You can remove the relay and jump the terminals to see if the fan operates. If it is the sensor you will have to replace it. I am not sure what the stock sensor range is for an 81 but I installed a 4 row aluminum radiator with dual fans in my 69 and used a sensor that turned them on at 200 and off at 190. Never a problem with overheating even in traffic at 100 degrees and 90% humidity.

 

[spikebot 81]

Hi guys. Was out driving the vette after 9 months off the road. I was doing mainly highway driving and the engine temp was getting up to about 260f, the coolant temp was staying at about 200f. When I got to where I was going I popped the hood expecting the electric fan to be running but it wasn't. From what I gather it should come on at 230f, but is that the engine oil temp or coolant temp? I would have thought it's engine oil temp. Am I right? If so I need a new thermostat. (Fan does run if thermostat is shorted)

The sensor for the aux. cooling fan comes on at 238 deg f and turns off at 201 deg f. It is controlled by engine coolant temp and there are no relays in the circuit. The sensor is located in the engine block, passenger side between exhaust ports, cylinders 6 and 8. My 81 never exceeded 195 deg f with the stock fan clutch system working correctly. The aux fan never ran, even with the ac running. Check your fan clutch assembly, thermostate, water pump, ect. Something is a miss.

 

[Antz81]

The sensor for the aux. cooling fan comes on at 238 deg f and turns off at 201 deg f. It is controlled by engine coolant temp and there are no relays in the circuit. The sensor is located in the engine block, passenger side between exhaust ports, cylinders 6 and 8. My 81 never exceeded 195 deg f with the stock fan clutch system working correctly. The aux fan never ran, even with the ac running. Check your fan clutch assembly, thermostate, water pump, ect. Something is a miss.

My coolant temp never went higher than the first white mark. Looks to be about 200f but could be 195f. It was only the engine oil temp that went up to about 260f.(which from other threads i gather is normal) When I got slowed down after coming off the highway it seemed to take a long time to cool down which I don't remember it doing before. If what you say is true then it seems I don't have a problem.

 

[Hib Halverson]

Coolant at 195-200°F?

You don't have a problem.

 

[Antz81]

Great. I like not having to fix something even more than fixing something