In '08 models of the GM vehicles sharing the "Lambda" platform including Enclave, Traverse and Acadia, GM built the V-6 using a defective timing chain.
These chains are prone to stretching which throws a trouble code 1st or causes major engine damage. GM/Buick's solution is to re-program the on-board oil life monitor to advise owners to change oil more frequently which will not fix anything. If the vehicle is still under warranty when the chains stretch, they will be replaced with completely different part numbers.
If not under warranty you are screwed for about a $4-$5K repair.
GM refuses to do a recall and there should be a class action pn this issue. Cargo door latch, steering squeaks