Which models and model years are you asking about?  That engine was used in the  2008-2011 Cadillac sedans (both CTS and STS) and was also used in the 2010-2011 Chevrolet Camaro, 2010-2011 Buick LaCrosse, 2009-2017 Chevrolet Traverse, 2009-2016 GMC Acadia, and 2009-2017 Buick Enclave.  I cannot recommend any of those vehicles especially beyond 100,000 miles.

Anyways, the LLT 3.6L V6 (primarily from 2008 to 2012) still had timing chain issues;  after 2012, the issue was less pronounced but not completely eliminated.  While GM design is to blame, but also lack of frequent engine oil changes (i.e. lack of diligent owner maintenance history) also did not help the situation.  If one buys a used vehicle with this engine it’s important that it had an impeccable service history.  But, I would avoid the engine and those vehicles if you can especially if the service history is spotty.

They were solid, later ones were better (like the LFX). What model & year car are you thinking of?

It looks like after the year 2012 they fixed some timing chain issues.

why do you ask?