Burning 3.9qts every 1000 miles

i like your style

 

You should rig up a 10q auxiliary oil tank that keeps your oil level steady like the one on the radiator, then you just keep it filled at “ok” and don’t worry about it.

Maybe consider hotter plugs and I’m serious on MMO in fuel, it seals things up good

 

Definitely switch to heavier oil. Might be cheaper too.

 

Are you sure you don't have PCV missing a baffle or something? I've never had a Prius engine apart, but most PCV connections on a valve cover, etc, have some type of baffle to prevent the system from sucking gases with significant oil entrained in it. Perhaps your "baffle" has broken/failed and the oil is not being removed before going to the intake system. This 'could' consume similar amounts of oil. If in doubt, maybe try an oil catch can like guys have been putting in the Gen 3s. Just keep a really close eye on it. Wouldn't want it to fill up in one day and make a huge mess. If it ends up working, you can just empty the catch can back into the engine and save big $$ .

PCV Valve Baffle vs. Oil Consumption Test Study – M/E Wagner Performance Products

 

Second gen PCV valve screws in at the valve cover. Don't attempt to remove the valve with an open-ended box wrench: lots of owners have done this and crunched a hole in the valve cover, when the PCV valve breaks loose. Use a closed box wrench (uniform radius at the end), or even better, just avoid box wrench, use a deep socket. Of course the hose needs to come off first.

 

Here's another possibility....

In years gone by, back in high school, I had a friend with a '67 cougar and a 289. His grandfather passed it down to him. His grandfather dogged the s*** out of that car and fed it the cheapest nastiest oil available. It had so much gooey buildup under the valve covers, around the springs, etc, that oil couldn't flow back into the sump very well. He'd get the low oil pressure warning light if he went above 4k rpm because the engine would pump the oil into the head area and it couldn't get back down because the drain holes were so crapped up. .

We pulled the valve covers, cleaned it the best we could. Had to be very careful because you don't want chunks to drop into the drain holes and cause even worse problems by clogging the pump suction screen. We installed a hotter thermostat and better oil. We did oil changes every two weeks. Within 6 months, that engine looked brand new under the valve covers. Perhaps OP is having a similar issue, causing the PCV to suck oil out. Based on his description of the oil "brands" he uses to replace the high consumption, maybe he's caught in a downward spiral.

Synthetic oil is great at developing zero deposits, cheapo dino juice....not so much.

 

I sincerely love the optimism in your post! And I'm not here to tell you it won't work. All the normal reasons for a car dying have apparently not been enough to stop this one, so you might as well see how long you can keep it going.

Although, you are looking at buying ~210 gallons of oil to get to reach 300k at the current consumption rate. That's maybe $2,300 worth assuming you're buying the cheap stuff in quantity. Just something to think about.

Honestly at that burn rate I'd just start using other peoples' used oil. It doesn't stay in there long enough for quality to matter.

 

The PCV could possibly have helped, but the oil control valve never would have mattered for this situation.

Whatever you do, don't spend a minute or a penny on the P0420 problem until the oil burning has been totally cured, whether that's de-sludging or total engine replacement.

 

Well if you're reading from that chapter of the service guide you could also try playing early Black Sabbath albums backwards on the stereo. Worth a shot, right?

 

Given the situation you are in.......you should go for the thickest high mileage oil that you can find; something that ends in a 40 or 50.
But even that isn't likely to help much.
It will be a race now to see if the plugs all foul out or if the cat plugs up first.

 

No it doesn't.
It is an oil that is about as thin as water.......and is precisely the WRONG thing to do under the circumstances.

 

Straight 50 weight for the win!

 

Which is a little bit silly.......since YOU will already have "changed" the oil 3 times during that 3000 miles.

Oh........and thank you for spewing all of that oil out onto the roads.
Your car belongs in a junk yard; the sooner the better.

 

You apparently didn’t read what I wrote

IN FUEL

MMO should never go in the oil except as a soak

I put over 100,000 miles on a failed Buick 3.8 using mmo, if I missed a dose it would barely run and stalled out.

MMO in fuel is very very different than in the oil.