blowby

/ˈbloʊˌbaɪ/
noun
  1. Gas or fluid that leaks past a piston or seal in an engine, often reducing efficiency.
    • Excessive blowby can cause oil to enter the air intake system.
    • The mechanic said the engine had too much blowby and needed new piston rings.
    • We measured the blowby to check the health of the old diesel engine.
Synonyms
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