My 94 Cadillac Eldorado is overheating and I don't know why I did that thermosta water pump and everything don't know why it's over heating can anybody help

It's either a clogged radiator or unfortunately a broken head gasket. There are kits you can buy that tests your coolant for exhaust gases. Napa sells one called a Leak Detector Kit / Engine Block, Test Tools Inc. for $42.99.