Rep Power: 0

I'm more of an auto body tech than a mechanic, so I'm not sure what's up with my Honda.

Sometimes when I drive, and am idling, say at a stoplight, I'll notice the temp gauge needle slowly rising up to the red area but not into the red area. When I start moving again, the needle goes back down to normal range. It's only happened about 3 times, but it worries me either way.

I checked the coolant level today and it's below the min. line in the plastic resovior (about 2 inches) and I can't see any coolant in the radiator. The oil level seemed normal when the car was running warm. So is it just reacting to low coolant or is there another problem like a blown head gasket?

 
Rep Power: 245

You should start with adding coolant. Top off the radiator when it's cold and add coolant to the res so it's between the min and max level. Then check it again after you drive it and it cools.

What year Civic? Some require bleeding.

A blown head gasket would be indicated by white smoke out the exhaust, grey coolant, or grey oil.

 
Rep Power: 244

I agree with sql on their advise above. If it's indeed a 6G, they don't need to be bled. Another thing. If after filling it properly it gets hotter and hotter at stoplights, the thermo switch may have been cooked. They are relatively cheap and an easy fix.

Otherwise if you gobble down tons of antifreeze soon after filling, the head gasket may be to blame (typically you'd see white smoke or very rough running at startup as stated above).

Let us know what you find. Good luck!