Has anybody on here been successful soaking the rings e.g. overnight with MMO through spark plug openings and drastically improving mysterious oil consumption? (no leaks, no smoke neither on start or on acceleration but using a qt every 500 miles at highway speeds...less in city driving)

 

A quart every 500 miles and you're not seeing any smoke?

I had an oil consumption problem, I tried every trick in the book... Piston soaks, different oils, Auto-RX, etc.
Nothing helped.

You need to pinpoint your issue. Have you done a compression/leakdown test?
Maybe your rings are toast, maybe your valve guides are?
You can try a piston soak... I know a few people who had a little luck with Seafoam.

 

The engine has only 80k miles of mostly city driving.
Compression test is not going to show a seized oil ring. BTW, it's good on mine.

 

What engine is it? What type of oil/filter have you been using? What are your OCI's?

I know a compression test won't show an oil ring issue, but it's good to do a compression/leakdown test to see if anything stands out.
If they come out fine, you can attribute your loss of oil to the oil rings.

I still cant belive you're not seeing any smoke at high RPMs....

 

D16y7 (it's a Civic and I know I am at the wrong forum but my q is about effectiveness of MMO on stuck oil rings) using QuakerState 5W30 and Fram filter on my Hondas for almost 3 decades. 85 Prelude was 21 years old and no oil consumption issues when I parted with it.

Seeing no smoke means the cat is doing its job. BTW, I just passed smog with flying colors.