2011 Prius One needs engine (180k;160k mine) - Should I save her?

Apologies that no one has responded to you yet... The best long term solution is to find a used Gen4 engine to put in it. Toyota failed horribly on Gen3 engines by boosting MPG at the cost of longevity. There's a mobile mechanic on here who's based in Oklahoma and once you find a decent Gen4 engine he can show up and do the engine swap in your driveway in one day for a labor charge of $1500. So for a few thousand dollars or perhaps more you can be back on the road for many more hundreds of thousands of miles.

 

If you want a nightmare install a gen 4 seems to be the way to go. Especially since OP clearly cannot diy. Best solution is to get a low mileage gen 3 engine from the jdm resellers. 60k mile motors just barely broken in.
Now to the old engine:
So you can verify the engine has engine physical damage? Scored cylinder wall? Piston damage? He gave you photos? Judging by his quote of 10k he sounds like he's a scammer like some mechanics are and may be lying since the clogged cylinder rings are a good enough issue to make you believe it. How many miles is it taking for you to add a quart? Did you have a compression test done and obtain numbers for each cylinder? What are the cel codes for the check engine light? Have you changed the spark plugs recently? Burning oil will coke them up well and make them not fire well enough to cause a misfire on oil burners. How many miles do you go between oil changes?
I think gen 3 priuses are fine. We've slowly bought a fleet of them in real life and they are easy cars to maintain with small fixes & mods. I supposedly have the worst prius ever built reliability wise and I've gotten it to be the most reliable car I've ever owned and helped lots of friends and family with them in the process.

 

Specifically, they used piston rings with less spring, to reduce friction. Also more prone to runaway oil consumption, around 150k.

Sometime in model year 2014 they switched to more springy rings, and pistons to suit. If you compare Fuelly mpg ratings of 3rd gen Prius model years, the 2015’s give up about 0.1 mpg.

either a salvage engine, a rebuilt engine, or refurbish the head and replace the short block* with new, are viable options. More info in attached. In particular, the part numbers for the gasket kit (includes new head gasket), revised piston rings and pistons, new head bolts (just to play it safe).

I would also replace water pump (the engine coolant pump) and it's thermostat.

The mechanics who “won’t touch it because it’s a hybrid” aren’t worth talking to; hopefully you can find some with more smarts.

* Short block is the portion of engine below head gasket and upper oil pan. It’s the cylinders, pistons crankshaft, the heart of the engine. Available new from Toyota for less than $2K. It will have the revised rings and pistons.

 

Why in the world would you install the same engine that will fail again in multiple ways when the next iteration of the engine fixed all those problems? It's not a nightmare to install, it can be done in one day.

As for doubting the mechanics diagnosis, maybe re-read OP's first post about how its burning oil, which is a know problem with the bad design elements for Gen3.

 

I follow him on Instagram: https://www.instagram.com/skimmilkhybrid Also his website: https://www.skimmilkhybrid.com/

He's also here on Prius chat and can't find that info at the moment.

 

He lives in OKC and could travel to you. LOL I actually had someone from TN call and ask about y Gen 2 for sale. It would be a Days drive for me...but I've had a lot of out of state interest. Engine replacement is a good choice if the rest of the car is in great shape you you love it.

 

I posted this yesterday for another recent gen3 victim. Yes your engine is toast, excessive oil burning is so common Toyota was fixing it free in the early years. There are fanboys here who either don't believe it or want you to spend $800 on egr work first. Changing the engine is the same as in a Corolla, the local mechanics may not know it.
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There are several new to you engine options. Plenty of cars have replacement engines.

1. Straight junkyard used engine. No rebuild of anything, no new gaskets, no real guarantee. Generally the lowest cost. $1500-$2500 installed. Could break two weeks later, could be a severe oil burner, could be a disaster. But often tried, high risk, low cost.

2. A JDM used in Japan engine. Usually some guarantee, higher installed cost, maybe $2500-$3500.

3. A used engine with a partial teardown and inspection, reassembled with a machined head and new gaskets. Typically solves head gasket issues and oil leaks on the used engine if existing. Some guarantee. Maybe $3000-$3500.

4. A used engine with a complete rebuild including teardown, inspection, new rings, bearings, machined head but with existing accessories like water pumps. Often a decent warranty and best bet for 150,000 miles. Usually the dealer option. Sometimes a dealer will include a complete new short block (bottom end with pistons and rings) $3500-$7000.

5. Similar to #4, a complete rebuild by a professional engine shop shipped to your local mechanic for installation. Often better quality than a local shop attempting a rebuild. $3500-$5000.

Typically auxiliary parts are replaced as needed or if requested on top of any of these options. Water pumps, thermostats, intake manifolds, plugs etc if yours are carboned up or bad. Extra cost but usually definable upfront.

Pricing varies but a knowledgeable owner can shop and get real value. Dealers are often half again to twice the cost of better independents.

Number five from HybridPit in socal:

 

He hit it on the head on pricing. JDM engine installed for $3500 would make the car worth while. $10,000 engine in a $5000 car? No.
See if the mechanic can get you compression numbers, and if you can make a good guess at how many miles it takes for you to add a quart. A lot of the times the sludgy ring issue can be reversed or at least improved to acceptable.
I did a piston soak on my gen 3 that was burning oil and it completely reversed my oil consumption. It was consuming 1.9qt/10k miles at 95k with me. Now at ~220k its consuming less than half a quart every 5k miles. I did egr, pcv valve , trying thicker oil etc... Nothing changed oil consumption. At my worst around 190k I would burn around a quart every 1500 miles on average and on the interstate it would increase consumption even more. Figured I would try a piston soak on the car and it improved dramatically to where i am now. Now the car really has no issues.
I just change the oil every 5k and make sure to get the EGR system in check.

 

Hi Jonda, I’m Skimmilkhybrid. You can call or text me for that 4th Gen. Swap. No problem.

405-696-9828, I’d be happy to help.