3.8 V6 overheating
 

This questions is on my dad's 93 sable w/ 3.8 V6. This car has only approx 50k miles!!! He said the water temp gauge was reading higher than usual the past day. After letting the car idle from cold to hot, I noticed that the electric fan was not turning on, even though the t-stat opened up at the right time. The radiator and overflow tank are both not low on antifreeze. The temp gauge was getting pretty high towards the red so I shut the car off. When it cooled down I let it idle again. This time the electric fan did come on, but it seemed to come on a little late (higher temp) than usual and seemed to shut off a little earlier than usual (temp did not go down as much as it should). I am unfamiliar with this engine but is my problem a temp sender or the fan switch? Please be as descriptive as you can as I do not know the location of anything and this is my dad's daily driver, thanks.

I am not sure but I would say sounds like the Thermostat is going bad. I went through 4 of them on my 3.8L. It would stay at the same temp for about a year or two and then it wouold start getting hotter and hotter. I would replace it and then it would stay the same temp for another couple of years.

well, at the temp the t-stat should open it does. i say this b/c the upper radiator hose became pressurized and hot when the temp gauge is about 1/2 way up, which is when it normally opens. like i said, the fan comes on late, or never does at all, u still think the t-stat is suspect?

I am wondering if the sensor that controlls the fan is going bad. That is about all I can think of if it is not the alternator. I am not sure how those fans are controlled. What shape is the radiator in?