what could be wrong with my golf gti 2002 model ?

To cut a long story short : bought this golf gti 2002 plate 3 days ago , on way home it told me to stop due to water leaking , ( took hours get home ) next day person i bought car off sent someone to look at it , possible crack in rad , next day bought some rad well he put in car stopped problem ,, but temp gauge did not go up although told to stop . and water kept emptying , later that night ( now have engine management light has came on ?? any one has any ideas plz