2005 Trailblazer fan running when first turned on
I've been reading up and watching videos on how to do a coolant change and in some of the videos, they talk about idling and waiting for the radiator fan(s) to cycle on. But I've noticed that my fan comes on right after starting the engine and stays on as long as I idle. I have no idea if/when it turns off when driving (is there a way to tell?). The engine is stone cold when this happens and the A/C is not on. The fan doesn't come on if I just turn the key forward without starting the engine. It comes on after starting the engine. The temp gauge is at the lowest point.
No codes. No overheating. Seems to drive fine. Temp gauge rises until it reaches just a hair passed half and stays there (which I read is normal and these gauges are not really showing actual temp all the time but should show overheating). Coolant looks fine in reservoir and radiator cap. But I'll see what comes out when I drain it.
Last year the water pump was replaced at the dealer after I noticed a noise and could see the fan moving off-balance.
Is the behavior I describe the normal operation of the fan? Or should the fan only be coming on when reaching certain temp?