All you're going to do if you break up the sludge is block an oil galley, your pickup, or block some tiny oil passage for something important like a turbo.
It's pretty simple, an oil that resists friction as much as possible will always run cooler but when you remove it, it's like running coolant as oil instead of just using oil. The thicker oil sticks around a lot longer because it's fucking awesome, but the other shit, if there's enough of it, will always let the engine be more efficient. Simple physics up in here.
When guys with older semi trucks change their oil, they’ll dump the old oil in the fuel tank. My old boss would do this with his CAT powered 359 peterbuilt. Truck was a beast.