69FJ40 dipstick tube leak (1 Viewer)

[Do Over]

The PCV is really just a one way check valve. If the valve cover is positive most likely because the valve stems are leaking or PCV is plugged causing a positive pressure in the crankcase and fumes coming up around the push rods. Today this is part of the emissions. Prior to emissions it prevented a gas/air mixture from exploding in the crankcase. Bad enough blow by as the fuel/air in the cylinder ignite and leak by the rings and explode in the crankcase. The draft tube on the oil fill was designed to remove the fumes. The PCV was just more efficient using the vacuum in the intake to draw it out.

Removed filter at oil fill, added PCV and connected to the carb. All in = $26. Low idle has cleaned up.