Wait until the engine is cool, then carefully remove the expansion tank cap and fill the expansion tank with engine coolant to the top of the filler neck.

Attach the pressure tester (A) (commercially available) to the expansion tank. Use a small adapter KE-30-5 (B) (commercially available) to attach the pressure tester.

Apply a pressure of 112−146 kPa (1.14−1.49 kgf/cm ² , 16−21 psi).

Inspect for engine coolant leaks, and a drop in pressure.

Remove the tester, and reinstall the expansion tank cap.

Check for engine oil in the coolant and/or coolant in the engine oil.