Crankcase

Fixing an Oil Leaking Crankshaft Seal

Watch Video  Source: Scotty Kilmer

How Engine Lubrication System Works

Watch Video  Source: Automotive Basics

Adding Sea Foam to Oil and Crankcase

Watch Video  Source: KRS

Cylinder Blocks and Crankcases

Watch Video  Source: Petes Garage

PCV Valve Related Symptoms and Problems

https://www.24hourmobilemechanics.com/pcv-valve-related-symptoms-problems/
The PCV valve is an inexpensive and the part most consumers overlook. It is also one of the causes of many engine problems.
Source: 24 Hour Mobile Mechanics