Bad Head Gasket? any ideas

well i have had a on/ off problem with the TT running warm about 1 notch past half sometimes. i replaced the rad temp sender, the "Blue" sensor, and the fan control module, i noticed a few hundred miles ago the antifreeze was low so I added some, now I went to drive it today and it was low again, I have never seen any leaks in the garage. I dont drive it very often in the winter due to the bad roads around here. and I know from a previous civic and cadillac Northstar if a head gasket is letting go the antifreeze will be burned. I have never smelled any antifreeze in the engine bay. I also know they ran a little warm but not in the red hot when the head gasket is letting go . the car has right at 100,00 miles. what do you guys think? any diy for a head gasket install I guess i will do the timing belt again even though it was done at 75~80 k by the previous owner, but about 3 years ago. any test you guys would suggest?