What causes a Jetta to lack engine oil?

[ColeLynn]

Jetta lacks engine oil due to reasons such as aging valve stem seals, piston ring issues, excessive wear, and sticking problems. Aging valve stem seals: Rubber loses elasticity, causing poor sealing, allowing engine oil to seep into the combustion chamber and burn. Piston ring issues: Excessive clearance between piston rings and cylinder walls, improper piston ring installation, or degraded sealing performance, weakening the oil ring's oil scraping function. Excessive wear: Excessive wear gap between the guide and valve stem, causing oil droplets from the valve cover to enter the combustion chamber along the gap during driving. Sticking problems: The crankcase ventilation valve sticks and cannot move, losing its function of controlling ventilation volume. Excessive oil vapor in the crankcase then enters the intake pipe through the crankcase ventilation tube.