Any suggestions why my 2016 Prius c with 96,000 miles has a hole in the 4th piston and they’re recommending a new engine? I just had the spark plugs changed out and they were the incorrect size but once even after putting the originals back in the car wouldn’t start. The electrical turned on not the engine.
Well, a hole in a piston is a good reason to replace an engine, no argument there. I mean in theory you could pay to disassemble that engine and have the one piston replaced, but it's a very labor intensive job and there is substantial risk that the broken piston pieces have been scattered throughout the rest of the engine which puts all the other parts at risk of premature failure. So I would agree that engine replacement is the most cost-effective cure for this problem. As far as the cause? On the "incorrect size" plug: A spark plug that is too long could certainly have caused this, but in theory all four plugs were the same, so all four pistons should have similar damage. Perhaps one broke catastrophically while the other 3 are merely dented? Another possibility is that the size wasn't the problem. There are many counterfeit spark plugs on the market these days, and they have been found to be of poor quality. There have been cases reported where pieces of a new plug broke off inside the combustion chamber where they would have caused damage to the piston crown, cylinder head and cylinder bores. Whomever replaced your plugs has some things to answer for. Good luck!
+1! If I woke up in your shoes? I'd give you your shoes back. Then? I'd replace the engine with a used one - preferably from a reliable independent mechanic and DEFINATELY not the one who is ....um....wholly responsible for cylinder #4.
2 questions: 1) were you having symptoms 2) who took the pics? (not that i'm cynical about dealerships or anything)
Thank you so much for the informative reply. Very helpful information. It’s still in the shop, hopefully she’ll be back to good as new ;-)
