Ever notice that nice layer of oil caked inside your intake tubing and intake manifold? Yeah, that’s thanks to your car’s stock PCV system constantly routing a nice fine mist of oil right into your intake tract every time you drive. Over time, that mist will grow into a nice buildup and could start to hurt your car’s performance. Now, don’t run straight out to your car and yank off the PVC tube, because the system does serve a pretty important purpose. Using the intake system to keep a slight vacuum on the crankcase at all times helps keep a better seal on the piston rings, and helps to vent the crankcase pressure.
In this video from Moroso you can see firsthand just how much oil can be pushed through the PCV system even under normal driving conditions. For the video the guys at Moroso built a clear-bodied Air/Oil Separator and hooked it up to a 24,000 mile, bone stock, LS6 equipped Cadillac CTS-V and took it for a spin. The video’s caption tells us, “You can see a puff every time I lift, and oil running down the sides under hard acceleration and heavy downshifting as well as at the end when I am just driving back to the plant. [At] 1:24 I am downshifting and it pulls a lot. [At] 3:14 is a long acceleration and lift and it pulls a lot. Under normal driving conditions, (driving like my Mom) I get about 3/4 of an inch of oil in a week. I think you get the idea.”