Originally Posted by Imp4
This is an unanswerable question in this forum unless there is a standard to measure by across products.
Some will give you marketing info, others will post personal preferences.
No one will state the ASTM and/or ISO standard and associated data by which they are comparing products.
Best answer yet!
Every oil claims that it does a better job of cleaning your engine. Ever see an oil advertise that it will leave sludge & varnish?
Assuming that they all work.......then no oil will leave any sludge & varnish, and you would not need to find another oil to clean off what the last brand of oil left behind.
Only one way to find out. Get a poor condition motor from a junk yard. Find a way to measure how much sludge & varnish there is. Then run the oil in the motor for however many engine hours it takes to equal an oil change interval. Drain the oil. Measure the sludge & varnish again. See if that oil actually cleaned any of it out. You will need to repeat the experiment at least 100 times to see if you can replicate the results, or figure in the percentage. Then duplicate the experiment with different brands of oil. After which you will have enough statistical data to analyze.
I don't have the ability to perform this experiment, then repeat the experiment a few thousand times, to validate results. Any volunteers?