iamdub
Full Access Member
View attachment 266810 View attachment 266811 View attachment 266808 View attachment 266809 You were 100% correct, the 2013 has the new style valve cover , but the drain hole in the PVC drain was patricianly clogged. I have a 2013 Tahoe with 130,000 miles and noticed having to add 1-3 qt oil between changes. Researched WWW and found one issue was the drivers side valve cover design and GM finally changed the design. I found out that about 2011-2012 the new design started being put on. All my process of elimination still pointed to the cover with PVC drain hole getting clogged. I ordered a new GM OEM part # 12642655 from RockAuto , all gaskets and bolts ( about $70.00). I enlarged the std 7/64 drain hole in the PVC baffle to a 5/32 hole, I also put additional drain below the baffle plate. I removed my original valve cover and found that the PVC drain hole was slightly clogged and most likely causing oil to be sucked back into the intake. I could have put in a catch can but wanted to try this first. The top end looks real clean, due to scheduled oil changes and all lifers are tight without any play. I have included some pictures of the old cover ( the clog is hard to see) and the new cover with the modified drain hole. I will monitor the oil consumption.
Don't trash your old cover. Someone here with an older, pre-2011 model could use it. They can easily be cleaned.
I'd strongly suggest you still get a catch can.