How to Use the AUTOOL SDT205S Smoke Leak Detector

The AUTOOL SDT205S is an automotive smoke leak detector. This guide turns the current model-specific controls and official operating sequence into a practical start-to-finish workflow.

Before you start

Work in a clean, well-lit and ventilated area. Stabilize the vehicle, keep rotating or hot components out of the work zone, and open the exact vehicle procedure for the system and test point you will use. A tool connection is not automatically safe just because an adapter fits.

• confirm that the model label reads AUTOOL SDT205S and that the controls match this guide;
• inspect the housing, cables, clamps, hoses, fittings, seals and adapters for damage or contamination;
• confirm the required supplied accessories are present: Power cord ×1 Included, Smoke outlet hose ×1 Included, Cone adapter ×1 Included, Valve core wrench ×1 Included, EVAP connector ×1 Included;
• identify the permitted connection point, test range, vehicle state and acceptance criteria before connecting;
• keep eye protection and the task-appropriate gloves within reach; and
• plan how you will return the vehicle circuit or line to its original sealed condition after the test.

Use the AUTOOL manual download center to locate the current instructions when a manual is available. The delivered model label and current vehicle service information control if an older image or remembered setting differs.

SDT205S controls and specifications

The current product record highlights Air Mode and Smoke Mode, Built-In Air Pump, Pressure Gauge Monitoring, Flow Meter Window, Flow Adjustment Knob. Confirm each relevant control on the physical unit before use; related AUTOOL models can look similar while using different ranges, air sources or operating modes.

Specification or function	Current model
Input Power	DC 12V
Testing Oil Fill Volume	10–15 mL
Rated Output Pressure	＜15 psi
Rated Output Flow	＜6 L/min
High-Temperature Protection	Stops working above 75°C
How It Works	Low Oxygen Combustion
Rated Power	65W
Response Time	Produces smoke in 5 seconds
Flow Meter Window	Included
Pressure Gauge	Included

Stay inside both limits: the tool’s rated range and the vehicle or component’s permitted test range. When they differ, the lower applicable limit is the boundary. Do not infer a missing gauge, adjustment, mode or protection feature from a higher model in the same series.

How to use the SDT205S

Step 1: Add Testing Oil

Fill 10–15 mL baby oil or liquid paraffin into the detector before use. Do not overfill.

Before moving on, pause and check the connection against the physical labels. A secure-looking connection can still be the wrong port, polarity, range or adapter.

Step 2: Open the Regulator

Gently turn the knob to open the airflow regulator valve, then select Air Mode or Smoke Mode for the next step.

Step 3: Connect the Test Line

Access the system to be tested and position the detector near the test area. Disconnect the line you want to test, then connect that line to the detector.

Step 4: Connect 12V DC Power

Connect the detector to a 12V DC vehicle battery, then turn on the power switch to start the detector.

Step 5: Observe Pressure and Flow

Monitor the pressure gauge and flow meter window during the test. Adjust airflow carefully to suit the connected test line and test setup.

Step 6: Locate Leaks

After smoke enters the connected test line, inspect for escaping smoke to locate leaks. Use a headlamp if necessary for easier inspection.

Do not end the job at the first plausible indication. Repeat or confirm the observation under the same controlled condition, then restore the vehicle connection and check for leakage, warnings or an abnormal response.

Read and verify the result

Compare the observation with known conditions, not with a single memorized number. Check whether the reading, indication or visible result is stable, repeatable and produced with the correct setup. If possible, compare a known-good point or repeat after correcting one controlled variable.

• A repeatable result at the correct connection is stronger evidence than a momentary spike or one brief indication.
• An out-of-range result can identify a direction for diagnosis, but it does not name the failed component by itself.
• A normal result at one test point does not clear every part of the system; follow the vehicle diagnostic tree.
• After a repair, repeat the same controlled test and complete the vehicle-specific functional check.

Common mistakes and care

• Testing oil is not included.
• Use liquid paraffin or baby oil as testing oil.
• Only refill when smoke becomes thin.
• Drain old testing oil before adding fresh testing oil.
• Do not operate continuously for more than 8 minutes.
• Wait for the detector to cool down if overheat protection is triggered.
• Do not refill testing oil while SDT205S is running.
• Do not borrow a range, mode, connection order or interpretation rule from another model in the series.
• Do not disconnect a live electrical, pressure, vacuum or fluid connection; first return the tool and vehicle system to a safe state.
• After use, clean only as directed, keep ports capped, coil leads and hoses without sharp bends, and store the kit dry.

Frequently asked questions

What Testing Oil Should I Use for SDT205S?

If dedicated smoke-testing oil is unavailable, use liquid paraffin or baby oil. Testing oil is usually not included.

How Much Testing Oil Should I Add?

Add 10–15 mL testing oil before use. Do not add more than 15 mL each time. Refill only when smoke becomes thin, and drain remaining testing oil before adding fresh oil. If too much oil is added accidentally, drain some oil out before operation.

Can SDT205S Directly Test Automotive A/C System Leaks?

No. The automotive A/C system operates at about 1.7–3.0 MPa output pressure, while AUTOOL smoke leak detectors generate much lower pressure. SDT205S cannot directly pressure-test the automotive A/C system for leaks. Use smoke only to help inspect an A/C line section after isolating and pressurizing it according to the service procedure.

Final SDT205S checklist

• Exact model, permitted test point and test range confirmed
• Tool, leads, hoses, seals and adapters inspected
• Setup completed in the model-specific sequence
• Observation repeated or otherwise verified
• Vehicle connection restored with no leaks, loose terminals or open ports
• Tool shut down, cleaned and stored without trapped pressure or unsafe power

Used this way, the SDT205S supports a disciplined diagnostic decision: prepare the correct test, control the setup, verify the observation and leave the vehicle in a known safe state.