I have a 2001 mustang with 80k miles on it. Everything was running fine with it last year then i got into a wreck and it sat for a year until i could get it back on the road. Well after a few days of driving it i noticed that my air conditioner would stop working after i had been driving my car for 5 minutes or so so i got it vacumed and filled but it still kept getting warm after a few minutes of driving. I then noticed that there was a wet spot under my passenger dash that was kind slippery. Finally I noticed that after my car is running for awhile it was overheating going all the way to right before the red on the gauges. I decided to do an experiment and took it for a drive until it got heated up and then i turned the heater on full blast and sure enough the temp. started to go down and got almost all the way back to normal operating temp. before i made it home. At first i was worried i had a blown head gasket or warped heads and that was the cause for over heating because when i changed my oil it did look like there was a little bit of water in the oil. However the more i think about it the water might just have been because the car sat in the same spot for a year and there was condensation. I have a feeling that the air conditioner is turning off because my car is over heating and the car is over heating because of a dead heater core however i have no experience with any of this. So please let me know what you guys think.