Engine knocking/shaking at 236k. Worth trying to fix?

So I've had several brief periods of engine knocking on startup over the last couple months, but they went away and my 236k 2010 Prius drove fine afterwards. But a couple days ago, I was idling a lot waiting for my girlfriend to finish errands, and after another 30 minute idling session, my engine started knocking and shaking hard. I shut it down, and then made it home OK. But the next day it was knocking a lot while driving, so I cancelled my drive and lurched home. I noticed that the coolant was a little low (not super low), so I refilled it. And I added oil. The next day I tried starting it and it knocked uncontrollably.

I've read all the threads I could find and it seems like there are several possibilities for what's causing it. Clogged EGR valve/cooler, clogged intake manifold, bad spark plugs, blown head gasket, crappy gas, etc. I ordered an oil catch can, but it will take a few days to get here. I did add some cheap gas before the recent knocking episode.

I'm not sure whether it's worth it to try to do all the repair options, since my car has so many miles, and because of my previous stupidity. My engine has been burning through oil pretty quickly, probably around 1 quart/2000 miles. And I've been topping it up fairly regularly, but only after I realized it was happening. This is my first car, and I didn't even know cars ate oil until I got the Low Oil Pressure warning a couple years ago, then checked my oil and it was super low. This was at 183k miles, 7500-8000 miles since the previous oil change. I started a thread about it here, and people basically said I probably ruined my engine, so it would eventually fail, just take care of it from now on and ride it out till it dies, etc.

I assume that since I was such an idiot, and then somehow managed to eek out another 53k miles after running my engine dry, it's probably not worth the effort to try to fix it this time. What do you guys think? I need a car ASAP for work, so I don't have the luxury of spending weeks troubleshooting. Should I at least try siphoning out the cheap gas and adding top tier gas? Or should I bite the bullet and do the whole cleaning of the EGR system and IM, replace the spark plugs, etc? Is there an easy way to check if the head gasket is blown?

(I should also mention that if I do manage to fix the engine, I still have to replace the brakes and rotors, headlight assemblies, left rear hub and bearing, and fix the horn. All parts I've long since bought but have been procrastinating installing, partially because I didn't want to put it all that effort just for my engine to die shortly after LOL).

Thanks,
Grady

 

Thanks for the replies. I drove my mom's new Outback today, and it was so nice and smooth that I decided it wouldn't be worth it to try to repair my old rickety Prius. Her low beams are literally brighter and farther reaching than my high beams lol. Even if I do manage to save the engine, which seems unlikely based on your responses, it probably wouldn't last much longer, and other parts would likely start failing soon too. Plus all the other repairs I've been putting off for so long would be a hassle to complete. Now I just have to try to sell my new/unused brakes and rotors, rear hub and bearing assemblies, headlight assemblies, and unpainted front bumper cover...oof.

It was a good run, I think, for my first car. I didn't treat her well enough, taking her reliability for granted. I should have done more research on preventative maintenance, used better gas, checked my oil more often and changed it myself. Lesson learned. I also drove her through many harsh Boston winters, specifically during every snow storm while there was a ton of salt on the roads, without one of my front fender liners for the last couple years too. I'm honestly kind of shocked she lasted this long.

I'll probably buy a new car since right now used cars are basically just as expensive as new ones. I won't be getting another Prius (which feels weird because it's all I've known, since driving my mom's Gen 2 for a few years before buying my Gen 3), because I personally hate the way the newer ones look. I was planning on getting a Corolla hybrid, but now I'm leaning toward the new Honda Insight. I can't imagine the Insight community being anywhere near as big or helpful as PriusChat, though. Thanks again for all the advice over the years.

 

Oh man, that would be a deal breaker. The HV battery is warrantied for 150k miles/10 years, but I'd be extremely pissed if it died at like 155k. I want my car to last at least 250k miles. And I drive 25k+ miles/year, so 150k is only 6 years. That would be atrocious.

Where did you read about the failing HV batteries? I haven't seen many people talking about it, or the Insight in general, because barely anyone owns them. Despite looking pretty great on paper, it's largely a failed car model. Honda might even discontinue it soon, when they bring back the Civic hybrid.