Oil Burning Engine with Marvel Mystery Oil

You are going about this all wrong......probably.

MMO will only help if there is a stuck ring.
It is likely that is NOT your problem........or anything else that "cleaning" will help solve.

The problem likely IS wear on the piston rings or the valve guide seals.
If that is the case, a thicker oil with "seal additives" is your only hope.
That is sold as "high mileage" oil.

If that doesn't help......AND THERE ARE NO ACTUAL LEAKS.......living with it or trading are about your only two choices.

If that much oil really IS making it's way out the tailpipe, it won't be long before the catalytic converter fails.......probably.

 

But the question IS.....

Why are you wasting your time with doing things that are guaranteed to NOT work ??

If you screw around long enough that the CAT burns up or plugs up, your "experiments" will come to an abrupt halt.

And have you given it a REALLY good physical inspection for actual leaks ??
Spots where it is usually parked ??

 

I thank god the 3rd gen has hydraulic valve cam adjustment. I don't mind doing screw adjusters, though I have to say with the last vehicle I did it on, it was *getting at* the valves that was the royal hassle.

But shim adjustment is something I've never done, nor relish. Any idea what the dealership would charge?

 

Whether it SHOULD be or not, it IS.
You are not being realistic in your expectations OR in your trial solutions.

I'm done.

 

I don't think PP oil will do much cleaning. 15W40 HDEO or any of the high mileage oils would be a better bet. Piston soak and/or oil flush is the best bet.
Despite what Easy Rider clams, some additives actually work. MMO is probably the weakest (but least expensive). Kreen is the most effective, but expensive and not available in CA (toxic).

Another thing you may want to look into is EGR cleaning. Not sure about gen 2, but it's a problem in gen 3 and one person said it helped with oil consumption: Prius III engine knocking at high torque low RPM (solved) | PriusChat

 

Shrug. Little smoke if you take care to evacuate fluid from cylinders before starting.

 

Back in the day- ( summer 1980 best I can recall) I had a temp use Chevy Vega while my Jeep was getting bodywork/paint done.
That car smoked and burned a quart a week... I ended up putting straight 50 weight racing oil in it, Castrol IIRC. Oil use went down considerably after that.

 

I know exactly how you feel- at one point- as a college student I had a old VW Bug, you could literally see the road passing by under your feet in some areas of the floor. Passengers thought I was kidding when I used to tell them to lift up their feet when going through big puddles- until the first time they got wet sneakers! But, I squeezed into every front row parking spot- next to every station wagon I could find, and in spaces sane people with nice cars wouldn't dare shoe-horn into. Heck... I never even locked the doors; I figured if anyone ever ventured inside they'd feel sorry for me and maybe leave me a few sympathy $$

It's absolutely liberating driving a car that the next repair is as simple as removing the plates and thumbing a ride home....

 

So, what did you fix in it?
How come do you collect so many prius cars?