My wife drives an 09 Enclave that we bought new. I just replaced an ignition coil last night (120K). It was the first engine related issue we've had. The car was rock solid until about 85K and we've spent about $5000 in repairs since then. In order to inspect the valves you have to take off the intake manifold to get the bore scope down the throat, but it is easier than you might think. I was dreading changing a spark plug (which we replaced at the 100K mile maintenance appointment) or having a burnt valve because of the issue you read about, but it was just an ignition coil going bad. So an easy fix for us, and I am just one data point, but so far so good at 120K. We are going to ride the vehicle until it cries uncle.

 

we've spent about $5000 in repairs since then..

Is that a misprint ???? I don't think I have spent that much money on both of our daily drivers and they have over 220K each on them, What in the world has happened to it that cost that much ????

 

Fair question.
Although I don't have a GM direct injection V6, I do have a direct injection VW 2 litre gas turbo 4. Experience with mine shows that indeed they do carbon up the valves, and I don't drive like a granny.
I'd like to see how people's experience is with the GM V6.

 

My experience with the 5.3 direct injection is yes they can carbon up the valves the engine venting /pcv orfice is to blame pumps a lot of oil/ condensation directly into intake DI makes it worse especially cold climates where water vapor mixes with oil residue and really gums up the valves ....... aftermarket oil separator catch can helps a lot even the pre direct injection LS motors with the pvc orfice venting benefit from an oil separator catch can you would not believe the oil / water vapor you drain out of can at oil change time looks like caramel pudding

 

the v6 3.0 l and 3.6l is one of the best engines made by gm.trouble free for the most part.been in the equinox since 2010 and cadillacs.impala 2012 and ahead.All i can remember doing is a high pressure pump on one and a cam accuator,thats in 6 years.