Toyota Echo

Hello!
Few questions:
before the "flushing" it was Knocking?
What weight oil are you using?

Usually the "clicking or tapping" its lack of lubrication on the upper side of the engine.

Knocking could be something else like a low octane gasoline a Knock sensor EGR etc.

Deep Knocking Engine Sound

Usually bad news. A deep rapping noise from the engine is usually "rod knock, " a condition brought on by extreme bearing wear or damage. If the rod bearings are worn or loose enough to make a dull, hammering noise, Sooner or later one of the bearings will fail, and when it does one of two things will happen: the bearing will seize and lock up the engine, or it will attempt to seize and break a rod. Either way your engine will suffer major damage and have to be rebuilt or replaced.

It`s a knocking or clicking (taping)