Quote Originally Posted by pitbullz
sorry if i didnt make it obvious :-) this is an alternative to using flushing oil for engines with really dirty oil. flushing oil as was said by numerous mechanics is ill adviced since it replaces the oil inside the bearings with the flushing oil itself and sometimes stays there. and many other stuff amongst that. but if the engine REALLY is dirty,like that for public use then flushing oil maybe needed.

also...prevention is ALWAYS better than a pound of cure...
Okay.

I was just wondering why it would be necessary to save the "fresh" oil which was used to "flush" the remaining gunk from inside the engine.

A friend of mine (he worked as a mechanic in his dad's shop while finishing an engineering degree, so he did know a lot about cars) once told me it wasn't always a good idea to use flushing oil (especially on an older engine) because it would remove old gunk from around the oil seals, causing them to leak later.