2000 venture

I have a 2000 Venture. the service engine light blink off n on. the van sound very bad when this was going on. i let it cold off n I check the water in the rad. all the water came out of the overflow bottle. i start it up today n everything seam to be ok. no light blinking i let it run for n hour to see if it overheated or anything i took for a ride everything seam ok. Does anyone have a clue what it may be? I was thinking it need to be flush or temp think need to be change.