Cracked open our 2015 today (lots of pics)

A little background: my wife just got a new Rav4 hybrid so I took her 2015 Prius Four with 173k miles. Up until now it has been dealer maintained, oil changes @ 10k, both coolant flushes done once, spark plugs @ 120k. Other than that nothing has been replaced or cleaned up until now. The car has never been out of eco mode and pretty much all highway miles.
I came to this forum because we had the engine misfire about 4-5 times intermittently in the morning over the last 6-8 months and I wanted to find out what was wrong.
After finding out about the head gasket issues the first thing I did was get the spark plugs out, pressurize the coolant and get a borescope down each cylinder. Luckily the head gasket is fine for now, no leaks and cylinders look great! That was a huge relief!
Next I took the intake off and the inside was coated with oil, with a small puddle under the throttle body. I didn't think it looked too bad compared to some of the pictures and descriptions I've seen online. The intake ports were also relatively clean. Egr tube had some deposits but wasn't close to blocked. The egr valve and cooler looked gross though. I didn't get the cooler out quite yet, hopefully tomorrow. I will also be swapping out the waterpump and t-stat and changing the coolant, cvt fluid and oil.
I feel like I got pretty lucky with none of this being done before and the head gasket being ok. Maybe a testament to the updated pistons and rings on the 2015? I attached pictures to see what everyone thinks.
I also wanted to say thank you to everyone on these forums! Without all this great info I probably would have just kept driving it until the head gasket or waterpump blew. I will post more once I get more done.

 

I did change the pcv valve and all the gaskets as well right away! That Easy Off Heavy Duty oven cleaner worked amazing, didn't even need to pressure wash it to get it squeaky clean.

Another thing that surprised me was the original waterpump looked flawless, still replaced it though since I took it out. I changed the cvt fluid as well and the old fluid was totally black, so that was well overdue for sure!

I will definitely be doing 5k oil changes from now on, as well as all the other maintenance recommended in this forum, I would love to see how many more miles and years we can get out of the old girl! I plan on adding an oil catch can soon as well, always had them on my forced induction vehicles but never knew they were relevant for the Prius.

 

@Mendel Leisk I haven't started to party but I am relieved that it didn't need to be replaced immediately. It is something I am planning for though and already got the double hex bit for it.

@ChapmanF I actually just replaced the egr valve with a new oem one so didn't bother inspecting the old one closely, but that is very good info for the future!

@ETC(SS) As of right now it actually looks really good underneath with minimal rust for wisconsin standards. This summer I think I'm going to apply something like that rust bonding paint to any steel underneath. Im hoping we can at least double the miles on it.

@Georgina Rudkus I replaced both the ICE coolant and the inverter coolant right away since I had it all apart and on the lift.

 

@ASRDogman @Mendel Leisk As always thank you for the tips! I've never heard of using linseed oil before so I will definitely be looking into that!