Minor Issues:
* Rough idle: The PCV valve helps regulate crankcase pressure. A faulty valve can lead to excessive pressure or vacuum, causing an uneven idle.
* Reduced fuel economy: Improper crankcase ventilation can affect air/fuel mixture, leading to less efficient combustion and lower gas mileage.
* Oil leaks: Excessive crankcase pressure from a blocked PCV valve can force oil past seals and gaskets, resulting in leaks.
* Check Engine Light: The PCM (Powertrain Control Module) might detect issues related to crankcase pressure and illuminate the check engine light, storing a diagnostic trouble code (DTC).
Serious Issues (if left unaddressed):
* Oil sludge buildup: A clogged PCV valve prevents proper ventilation, allowing blow-by gases (containing combustion byproducts and moisture) to build up in the crankcase. This leads to sludge formation, which can clog oil passages, damage the engine bearings, and ultimately seize the engine. This is a major concern.
* Increased engine wear: The sludge and increased crankcase pressure contribute to increased friction and wear on internal engine components.
* Damaged piston rings: Excessive crankcase pressure can blow past the piston rings, leading to increased blow-by and further exacerbating the problems mentioned above.
In short, while a bad PCV valve might initially only cause a rough idle, ignoring the problem can lead to significant and costly engine damage in your 2001 Silverado. It's a relatively inexpensive and easy part to replace, so it's best to address any suspected issues promptly.
