Are these cylinders too clean (head gasket failure)?

Hi all,

A few weeks ago, I turned on my 2012 Prius with 196k miles and got a dreaded death shake. It lasted a few seconds then quit, and I had no further problems for the duration of my ~20 minute drive.

I scanned for codes and it reported misfires in cylinders 3 and 4. Per the Car Care Nut's video on diagnosing head gasket issues, I decided to take a look with a borescope. I took everything apart, and in the process the boot for ignition coil 4 ripped due to being super stuck.

Here is what I found in the cylinders:


(are these scratches on the side concerning?)



While in there, I replace the PCV valve, installed 4 new spark plugs (NGK), and a new Denso ignition coil on cylinder 4. The first start after all that was a little rough (though much less severe than the first time) and I got a misfire on 2. I have used the car for two medium size trips since then and it has started up and ran very smoothly.

Some history/other details:

• The rattle I first noticed was in the evening, and that morning I had done two very short trips. It was also below zero outside.
• The only other time I have heard the death rattle was years ago (approx 2019?), also when it was very cold. It happened maybe once or twice.
• At 148k miles (2021) I noticed I had low coolant and refilled it. I have not lost any coolant since then.
• I changed the engine coolant at 190k (unfortunately I don't know if it had been done before when I bought it at ~140k)
• I cleaned the EGR system/intake manifold/throttle body at 185k (again, first and only time, didn't know to do it until then)
• Oil changes done around every 7k, but for the last few years every 5k

So, do these pictures look questionable? Is it possible that this was just condensation from short trips in cold temperatures? I'm committed to getting the HG replaced if needed so I can hopefully get many more miles in. If that is where I am headed, does anyone have a recommendation for a mechanic in the SE Michigan area? Thanks in advance!

 

One more thing - I have not noticed that the car burns any oil.