Cadillac Repair Questions? Ask a Mechanic for Answers ASAP
Hello I will help you with your question,
You have the Northstar problem that almost everyone that owns one from these years runs into.
The head gaskets leak due to the head bolts pulling out from the block with the heat cycles of the engine causing the coolant loss and overheating.
The only remedy is to rebuild or replace the engine. Sorry but it is the truth, please let me know how I can help you with this