-David-

I am a prospect buyer and am also very interested in this subject. I like to keep vehicles for a really long time. As of now I have not see anyone show borescope photos or any other evidence of how well these engines mitigate the buildup over time or miles or if they suffer from fuel dilution in the engine oil. A recent thread showed a catch can installed that was collecting oil/water mixture in the 6.6 which shows that the OEM separator is not 100%. Fuel type (top tier), oil type, oil change intervals, type of usage, etc. are all contributors. In general I do not like the idea of adding catch can in that the water/moisture caught can freeze and *might* inhibit gas flow of which can cause other issues. It surprises me that GM will not run a port and GDI system like Toyota and Ford are now using in lieu of straight GDI.

Also on the WT, an upgrade to 18" wheels and all-terrain tires will raise your GVWR by a couple hundred pounds.

I wish someone with a higher mileage L8T would borescope the intake and show what their intake valves look like.

I am looking at buying a 6.6 gas and plan on keeping the truck long for a long time. My concern is the GDI intake valve carbon issue and how well GM has mitigated it with their built in oil/air separator in the CCV system. Will the intake valves need periodic cleaning such as walnut blast or CRC chemical cleaning? Does it need a catch can? Has anyone pulled a CCV hose and seen oil passing through or has anyone borescope'd the intake after a good amount of miles? I know the earlier German GDI engines have had the worst issues, and that other manufacturers are using a dual injection (port and direct) system. I just wish GM would do the dual injection so I wouldn't have to worry about it.

Bump. I am also interested in this as well. Jay, were you able to find more information that you can post? As I understand, GM has patented a 2-stage oil/air separator system. I have found no positive indication that this new system is used on the L8T 6.6 gas engine. Does anyone know if the GM L8T 6.6 gas engine incorporates the new patented 2 stage oil separating system? A Chevrolet engineer being interviewed by Mr. Truck at 17:30 minutes briefly discussed an oil/air separator being built into the L8T 6.6 gas engine PCV system and he says that it will "completely" remove the oil from air entering the induction system and that only exhaust by-products are returned to be burned. This raises questions: Does "completely" mean 100% oil removal (no can required)? Has anyone installed a catch can on a L8T 6.6 and is catching oil in it? Has anyone pulled the PCV hoses off of the new 6.6 and has found oil passing into the air intake? Thanks David