IPA: /ˈkræŋkkeɪs/
KK: /ˈkræŋkˌkeɪs/
A metal container that holds the crankshaft and related components in an engine.
The mechanic opened the crankcase to inspect the engine's internal parts.
Crankcase → The word is formed from "crank" (from Middle English *cranke*, meaning a bent or crooked part) and "case" (from Old French *casse*, meaning a container or box). The term "crankcase" refers to the container that houses the crank mechanism in an engine.
Think of a 'bent part' ('crank') being housed in a 'container' ('case') — that's what a crankcase is.
No commonly confused words.