Don't know if this has been posted before, but I may have inadvertantly discovered a simple way to "see" the cleaning effect of Rx. Like many others have reported, I too cut open the oil filter to see if I could find any dirt after my 1st Rx application. But I saw no obvious dirt, sludge, varnish, etc., in the filter. Didn't really care at the time as I was really trying to stop a seal leak, not clean the engine.
Well, I just finished my 2nd leak application and this time saved a sample of the used oil in a clear glass jar. About 6 oz. It sat on the work bench for a week. When I disposed of the oil tonight, there was a clear layer of fine dirt left on the bottom of the jar after I poured out the oil. It was thick but eventually started to pour after the jar was tipped on its side for a half hour. It was also jet black in color with an extremely fine silt-like feel. Almost had no feel to it. I presume it's the "liquified" cleaning I've read about.
For what its worth...my experience.
Well, I just finished my 2nd leak application and this time saved a sample of the used oil in a clear glass jar. About 6 oz. It sat on the work bench for a week. When I disposed of the oil tonight, there was a clear layer of fine dirt left on the bottom of the jar after I poured out the oil. It was thick but eventually started to pour after the jar was tipped on its side for a half hour. It was also jet black in color with an extremely fine silt-like feel. Almost had no feel to it. I presume it's the "liquified" cleaning I've read about.
For what its worth...my experience.