Hello everyone. I just purchased a 2004 wrx wagon with 133k on the odometer. I took it to a subaru specialist, who did a once over, and he said the timing belt and water pump looked like it had been done at the suggested mileage. I was driving it yesterday for the first long haul drive (approximately 75 miles each way). After reaching our destination the car behaved normally, but on our way back it had started to warm up outside so we kicked on the A/C. When I have tested out the A/C in the past it got freezing cold right away but this time it didn't and I noticed the temp gauge rising. Pulled over, put the heat on full blast and let it cool down to normal temperature, which we drove with it on until we reached our next location. We went in for lunch and let it cool down, I went out and check the coolant level and noticed it was low and there was a strong odor of coolant coming from the engine bay but could only see a small puddle (maybe a couple ounces) below the coolant reservoir. I checked the dipstick, radiator and exhaust smell to see of any signs of a blown head gasket and there aren't any. I went and topped up the reservoir and let it idle with the A/C on and it started to rise once again. I let it sit for about another 30 minutes until it was time to leave. Once we left all seemed well with no A/C on then once I started driving up a hill the temp gauge was bouncing between the two mid way lines. After about 10 minutes of driving it started to rise above that so I pulled over and let it cool down. I proceeded to drive with the heat on for about 10-15 minutes and then switched it off and it was fine until I started to climb the street to my house. Started to rise again but once I parked it in my drive way and turned off the car to let my passengers into my house. I went and restarted it and let it run with and without the A/C on to check for coolant leaks and over heating not once did it do it for the 30 minutes I ran the car for. Also no noticeable leaks under the car and the coolant level seemed to remain the same from when I filled it up. I am about to go pop the radiator cap off to see if there any bubbles but I am not thinking it is the head gasket. All of the fans are running normal and I am going to check the lower radiator hose to see if it could be the thermostat, but i am thinking it might have something to do with the a/c as the fans appear to be operating normally. Any suggestions would be much appreciated to this Subaru newbie.