General method description: Check

If a leak is detected that is assumed to come from the valve system, first check that the piston in the relevant cylinder is at top dead center (TDC).

Then try to set the piston just prior to top dead center (TDC) and redo the test.

When repeating the leak test on the same engine, there are usually variations in the results of the measurements.

This is due to changes in the engine coolant temperature (ECT) and the piston not reaching the same position as in the previous test, and is affected by the amount of oil on the piston rings at the time.