Bought a 2005 Beetle w/ 100k miles for a first car about a year ago and lately I've been having a few problems with it here and there. My main problem is that once I get on the highway and start going 60+ and have the A/C on, the overheating warning light comes on and beeps, even if I have full coolant. Even if I don't have the A/C on, just driving it for about 30 minutes makes the light come on. When it gets like this and I keep driving it, it eats up a lot of coolant. Any reason it could be doing this? IIRC the dealership said it had a new hoses and a new water pump. Just needed an oil change and for the radiator to be flushed.