It is important to rinse the cleaning agent out of the engine with clean water before the drying run.
If not, whatever dirt etc that was on the compressor blades is then in solution with the cleaning agent and will just re-deposite itself onto the blades when the agent dries/ evaporates....defeating the object of the whole exercise. The cleaning agent will also leave a film on the blades that will attract even more dirt.
The drying run is not only to dry the compressor blades but to also prevent the onset of internal corrosion due to pooling water, blow through all the Pc air bleeds and prevent water from finding its way through labyrinth seals and into the oil and bearings.
I've got to say that if you've got cleaning agent coming out of your heating vents, it doesn't sound as if the cleaning procedure is being carried out correctly.
Last edited by nodrama; 23rd Oct 2009 at 15:27.