2007 chevy malibu overheating problem?

[keith b]

my chevy malibu tends to go past the half way mark on the gauge on the inside of the car. i have to add coolant every couple weeks but there seems to be no leaking in my garage or where i park my car at work. Also i noticed after driving for a long period the fans kick in after i turn the car off.

 

[k0urnel]

Same problem only mine did overheat and the temp. gauge goes all the way up. Once in awhile the light will just come on. I had the water pump replaced a couple months ago and it was fine til just recently. Same problem, have to add coolant. No visible signs of leaking either and I have been under the car as well, nothing. Coolant pressure test is my next thought. If I turn the heat on it seems to cool it down a little bit. I have a 2007 btw as well.