Anyone have any ideas as to why my 2013 Silverado 5.3 has started using oil? It has 104000 miles on it and has not used oil before. I was going to replace the PVC valve only to find out there is only a pipe in the valve cover. I did unhook it from the valve cover and it has oil around it. Still seems to run well. I have already disabled the AFM as I did not like it when I pulled my trailer with it. I use synthetic oil in it. Seems to use quite a bit, will have to monitor it closely to find out just how much. It doesn't smoke nor is there any oil on the pavement under the truck. Any thoughts would be appreciated. Thank you

 

How much oil is it using per week or weeks? At 104,000 miles its not that old or worn out. Piston rings and valve seals or guides may have gone south for some reason.

This is but one more reason I don't like AMF (cylinder deactivation) engines. Cadillac tried it years ago, and nothing seems to have changed much. Too many issues.

 

I thought the PVC might be the reason for oil usage, however as I have learned there is only the pipe that goes into the valve cover. So I disconnected the hose that connects to the pipe and sprayed some MAF sensor cleaner down it, "it's what I had available", and let it set for a couple of hours. Hooked it back up and everything ran better and I have not since noticed any oil consumption. It even gets a mile to two better gas mileage. It is actually running smoother than it has in quite a while. Could it be that something plugged the pipe and cleaning makes all the difference. Time will tell.....It idles like a new truck now, runs great. Thanks for responding Oilcan henry. Makes me wonder how big a hole is in the pipe that goes to the valve cover. Might have to take it off someday just to see for myself.

 

PCV valves go south, but at least they are cheap and easy to replace,,unlike other things. Cleaning the MAF sensor is always a good thing, as they don't often show a code when dirty or gone bad...

Back in the 1950's and earlier, the crankcase use to vent to atmosphere, though a vent tube on side of the engine block, like my father's old inline flathead 6 cylinder motor 1948 Studebaker did,.