Originally Posted By: SonofJoe
If you are a normal person...
Well, that just ruled out most anyone on BITOG...
Originally Posted By: SonofJoe
You correctly answered your own question.
If you start the engine and run it continuously, non-stop for a month, with a miraculous self-refilling petrol tank, you will strip off the light front end of the oil, the viscosity of the oil will go up, the concentration of DI & VII in the oil will go up and, should you sample the oil and test it, the Noack of the oil in the sump will go down.
On the other hand, if you continually short-trip through the arctic wastes of Southern England, never getting the engine warmed up, and continually condense the unburnt heavy-end of the gasoline into your engine oil, it will thin, additive concentrations will drop and the measured Noack of the oil in the sump will go up.
If you are a normal person, with a normal car, living in a normal temperate country and drive a normal mixed driving cycle, then the Noack of the oil in your sump might bounce around a tiny bit but to all intents and purposes will have the same Noack value as the fresh oil you added at the start of the OCI.
Works for me. That says my wife's car might see high Noack issues, as many of her trips are about 9 miles long. Coolant gets up to temp, but not so sure on oil temp. Probably fine in summer but winter might suffer. Me, most of my trips are 50 miles, so Noack would likely go down with time. So her car might like a low Noack oil, at least in winter, while mine probably wouldn't care--assuming we had cars that Noack was something to worry about (GDI fears). [Thankfully, no worries here.]