I am talking about the method of leaving a car in a low gear, running the engine up near redline, and then letting off, letting it engine brake and slow down. This seems to have relatively good success of freeing stuck piston rings that allow for oil burning. I have done this on several engines with about 50% success rates. Some are too far gone while it works wonders on others. The two most recent I can think of where it worked was a Cadillac Northstar 4.6 that had been run WAY beyond when it should have been changed on cheap oil and putted around town. I understand these engines are known for and almost designed to burn some oil so the rate went down by about 75%. It didn’t stop using oil but was at least tolerable.
The second one I recently did was another 1.0L 3 cylinder Geo Metro. It had been sitting for 6 or more months and it was obvious that the previous owners have not given the engine the TLC I would have. The oil I drained out was filthy and I basically replaced every seal and gasket in the engine with the exception of the head gasket. I could see sludge in the recesses of the engine and under the valve cover although the engine ran fine. I changed the oil after like 500 miles and this change looked dirtier than a lot of oil left in for 3000-4000 miles.
The main problem was oil consumption. There were no external leaks since all of that was taken care of and I double checked. No oil is leaking. There is also no smoke that I can see but about 1 quart of oil was disappearing every 1000 miles. I did about 6 cycles of “Italian tuneup” after making sure the oil was full. The car has been driven over 500 miles since with much of that being high speed interstate driving since then and the drop in oil level has been imperceptible.
So, how does this work exactly? I have heard that the engine vacuum under heavy closed throttle deceleration loads the piston rings differently and unsticks them if they aren’t too stuck. Also, if the engines treated this way are maintained better in the future with good oil and frequent changes, how much of a chance do the sticky rings have of returning?