i recently got a '94 STS a week or so ago, and the guy i got it from, told me the next morning, that he had driven it the night before, for about 20 minutes. he said that the car started running hot and all the coolant/water was coming back out of the cap. i assumed the cap was loose, so i bought a replacement one. unfortunately, the car still kept running hot. i replaced the thermostat, and it doesn't run hot as fast, but when it does everything comes out of the reservoir. not from the cap this time. i ran a system check (holding the off and warm buttons) and this is what came up.
No SIR Codes
No TCS Codes
i don't know what any of that means, so hopefully someone can help me, or can tell me what the problem could be. other than running really hot (goes up to about 250) the car runs good. needs an oil change and other minor things.