Cadillac Repair Questions? Ask a Mechanic for Answers ASAP
Being Proactive twards an issue like this is really somthing that starts much earlier than at 98k miles, But still is just as necissary now as it was at the beginning of the cars life. #1, Keep the cooling system clean and maintained by changing the coolant regularly. My recomendation is every 2yrs or 30k miles. #2, Replace rubber hoses if they are older than 6 years so they will not fail and cause an overheat. #3, Never allow the engine to overheat. Wich means you are paying attention to the coolant level and the the temperature gauge to catch and issue before it becomes large.
I have never found that additives such as that, To be affective in correcting or preventing issues. At best I have seen a additive like that Stop a head gasket leak for a few days. My general opinion is that those additives are a waste of money.