Welcome to 2CarPros. If you mean it is blowing white smoke out of the exhaust the most likely issue is a bad head gasket or failed intake gasket that is letting coolant into the engine. GM had issues with intake gaskets on some V6 engines over the years. Testing for a failed head gasket isn't hard and the tools are usually available as loaners from the parts store.
https://www.2carpros.com/articles/head-gasket-blown-test
Try those and see if it shows as a bad head gasket. For the intake gasket it depends on which engine it is.
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Saturday, July 6th, 2019 AT 12:15 PM