Smoke Test (Leak Detection)

What it is

What is a smoke test (leak detection)?

A smoke test fills the sealed part of a system — intake, boost pipework, EVAP or exhaust — with a low-pressure, non-harmful vapour, so any leak shows itself as visible smoke escaping from the exact point of failure.

It is the fastest and most accurate way to find leaks that no scan tool can pinpoint: perished vacuum hoses, cracked intake boots, failed intercooler pipes, leaking inlet gaskets, a faulty purge valve or a split exhaust joint.

Why it matters

Why this service is required

• Unmetered air entering after the airflow sensor upsets the fuel trims, causing a rough idle, hesitation, poor economy and eventually a check-engine light.
• EVAP codes (P0442, P0455 and friends) are an automatic emissions concern and are almost impossible to chase without smoke.
• A boost leak on a turbo engine robs power and can push the turbo into overspeed trying to compensate.
• Guess-replacing hoses and gaskets is far more expensive than one accurate test.

Warning signs

When to book this service