Full context:
I bought my car a couple days ago with a strange noise from the engine.
That was the noise when I bought it. I test drove it and took it to 60 mph a few times and did not hear it. it was only audible when the car was stationary and would get louder with RPM. The engine bay was completely dry, coolant had been done 6 months ago (originally green but changed to Euro blue after a few days, topped off fresh oil. The only other notable issues were presumably a bad AC compressor and a bad bearing.
I had about a two hour drive home. I only noticed the noice when I dropped into a lower gear while going ~60 mph. When I was an hour out I felt loss of power. The car wouldn’t go above 60 even if I downshifted. Subsequently, I felt the car hesitating (missing I think) and the rattle noise was louder. Then, I couldn’t hold 60 and the check engine light started flashing, so I pulled over. When I stopped the engine died. The engine had smoke coming from it as I popped the hood. I found oil all over the PCV and the bottom of the oil cooler. The engine did not over heat. I towed it back to my place and it would start back up but idle very loudly. It was 1/4 up the dipstick and the oil looked normal (although it looked very thin when the car stopped on the highway. The coolant was over full and dark green (pic attached).
The findings:
I pulled off the manifold and plugs to scope the cylinders. The one normal looking piston and cylinder is what the first four looked like. The fifth cylinder is what all those other pics are from (the cylinder closest to the driver side). I also pulled the codes which are attached.
To my knowledge the plugs haven’t been done in a while and the noise only started within the year. My friend who had an S40 suggested the combustion escaped through the damage piston and over pressurized the block, damaging all the seals. And whatever was in there seemed to have damaged my head gasket too.
If anyone could help shed some light on what could have caused this and what they’d recommend doing to fix it, I would greatly appreciate it. I understand a new piston, cylinder re-sleeve, and head gasket is probably in order, but is there more to the story that I am missing or is the engine not salvageable?