oil pressure vs pressure level

oil pressure and pressure level both are nouns.

Word	Noun	Adjective	Verb	Adverb
oil pressure	Yes	No	No	No
pressure level	Yes	No	No	No

As nouns, pressure level is a hypernym of oil pressure; that is, pressure level is a word with a broader meaning than oil pressure:

oil pressure: pressure that keeps oil on the moving parts of an internal-combustion engine
pressure level: the force applied to a unit area of surface; measured in pascals (SI unit) or in dynes (cgs unit)

Other hypernyms of oil pressure include force per unit area, pressure.

oil pressure (noun)	pressure level (noun)
pressure that keeps oil on the moving parts of an internal-combustion engine	the force applied to a unit area of surface; measured in pascals (SI unit) or in dynes (cgs unit)