Why is a smoke test valuable when diagnosing vacuum leaks, and what are typical leak points?

Why is a smoke test valuable when diagnosing vacuum leaks, and what are typical leak points?

• A. Smoke makes leaks visible; typical leak points include intake manifold gaskets, vacuum hoses, PCV lines, brake booster hose, intake seals, and throttle body.
• B. It measures vacuum with a pressure gauge at idle only.
• C. It seals vacuum leaks using smoke to prevent loss of vacuum.
• D. It determines engine timing by observing smoke color.

Answer: (A)