OVERKILL
$100 Site Donor 2021
We've seen mixed results on that front. The HEMI is probably more the exception, these are filthy running engines and I expect the material is from the ring land area, you most likely won't see anything this severe with other, cleaner running, engines.An important question though is:
If we all are using full synthetic oil, how are the engines getting so dirty with varnish and sludge in the first place?
I would expect that if you buy a new car, and only use a full synthetic oil, say for a reasonable oil change interval like 5k miles, that the engine's internals should be clean (no sludge or varnish) after 100k miles. Is something happening to the full synthetic oil to turn it into sludge/varnish that we are not aware of?
That said, the ring land area is probably the hardest to keep clean, and I suspect that despite the engines being clean elsewhere, this is the area where you'll see material get cleaned from.