So I replaced my brother's Camaro's radiator fan motor today since it died at some point and I was wondering if the fan is supposed to turn on immediately when you turn the key to the on position before starting the car? It's always done that and I have no idea if that's normal.

Also, it ran a little hot (to like 260 I'm told) from idling with the fan not working and I was wondering if that could have caused any damage to the thermostat? The guy at the auto parts store said it could have been damaged and if there's a chance that happened, I would want to replace it.

Thanks in advance!

 

Not sure about third gens but typically electric rad fans don't come on until they're needed. A couple of things will control them such as temp sensors or AC request. A dual fan system or a single fan with an auxiliary fan will have 2 different turn on temperatures.

Thermostats are in an engine to keep the coolant temp at a minimum temperature. They stay closed until the engine warms up then open at the rated temperature. If coolant temp gets too hot, the thermostat does nothing to keep it cool since it's already open. If the engine runs too cool from cold weather driving or a rad/fan system that's too efficient, then the thermostat will close to keep heat in the engine.

There's always a possibility the the thermostat has failed. They can get stuck open or stuck closed. If the fan is now working and coolant temperature is maintained at the proper operating temp then the thermostat is probably fine. Thermostats are cheap. If in doubt, replace it.

 

Fans should not turn on as soon as the engine is on unless the engine coolant is relay's energizing wire is grounded by whatever be it coolant temp or A/C. Wait until the engine is ambient temperature and the A/C is off. If the engine is off and the key is on and the fan comes on then pull the fan's relay that is turning on and check if there is a (-) signal at the energizing wire. If there is then you probably have a wire that is grounding out on something or possibly a bad temp sensor (if the fans runs off a temp sensor).

 

If the engine was already heated up then the fan could come on with key on, but shouldn't if still cold. Either someone wired the fan to always be on from a fan switch failure or you have a relay wire grounded somewhere or relay failure
Or as Tibo mentioned the AC or defrost lever is on

 

It's just one big fan behind the radiator and it comes on before you start the engine so something must be up.

I may replace the thermostat when it gets a little warmer just to be safe then. Thanks!

I'm not so experienced with troubleshooting electrical issues but when it gets a bit warmer around here I'll have to poke around and see if I can find out what's causing the issue. I guess it working too much is better than not at all for now. Thanks for the tips!

It comes on when it's cold so it seems something is awry. I wouldn't be surprised if the previous owner messed it up somehow as it used to have and amp in the back at one point.