Hi guys I got a 2011 cts 3.6. My ? Is if the timing chain is bad it will bend valves.... or I can get by by just replacing chain kit.... engine rattle bad and puffy smoke tru tail pipe

 

Interference Engines self-destruct if the chain goes. Absolutely Must replace Chains in a 3.6L if they're going out/loose. Engine Rattling is NOT a good sign. Quite common in the 3.6L engines. Good luck...

 

Unfortunately timing chains are common issue on the 3.6 motors. If they are noisy, they will need new chains and tensioners, plus any guide that is worn per inspection once opened up.

But.. worn chains should not make the exhaust smoke, just noise and check engine light. You may already have greater issues..