2013 head gasket replacement

My wife’s gen 3 started misfiring a couple months ago, haven’t driven it much at all since to be safe. Was only a misfire on cylinder 1, based off a mechanics recommendations I replaced all coils and plugs (properly gapped) rather than just cylinder 1. Still a misfire with what is now noticeable coolant loss, but no smoke from tail pipe yet. No compression loss, so hopefully no issues with a warped head, pistons, cylinders or valves. The back side of the block is wet below the head (found when I removed the windshield cowl) and the combustion chamber for cylinder 1 was wet when I removed the old plug and shined a light down there to take a look.

197k miles.

I’ve got the process planned out to replace the head gasket, but am running into a few things where I am seeing varying recommendations, and want to be sure I get some advice before continuing and have seen a lot of knowledge in this forum.

1. Replace ALL gaskets/o-rings in the process. I get the concept of why not since I’m already breaking the engine down, but buying all the other gaskets and o-rings for another couple hundred seems like a lot (trying to do this on a pretty tight budget). We also plan on potentially getting rid of the car in the next year or two, maybe another 20-25k or so miles. I’m planning on using permatex black for timing cover and cam carrier, etc. but wondering if all the other seals are worth it. I’ve seen recommendations saying it’s not a big deal and some saying it’s important.

2. Lubing head bolts. I’ve seen recommendations to use anti seize, 0W-20 motor oil, or assembly grease. Anyone have any experience with which one works best to get proper torque and degree rotation specs?

3. Removing stuck head bolts - use a happier to strike the top of the 12point socket while it’s on the bolt to help break it loose a bit before removing them to help avoid snapping a bolt. Seems like this works?..

Honestly I’m relatively savvy around engines, but still new and having never done a head gasket before, snapping a head bolt scares the hell out of me. Definitely don’t want to have to try and extract a broken bolt. (I will be using new head bolts as well)

Side question, when is the average mileage some of you all have noticed the hybrid system battery to be replaced? We’re at 197k miles on it, and take really good care of the car. I also plan on replacing the coolant for the hybrid system.


Again, we are considering getting rid of it in a year or two. 20-25k miles.
We absolutely love this car, but we are expecting a child and this is the older of our two cars so we are wanting to upgrade to something a bit bigger and safer once we save the money for the down payment on a new car.

 

This is great, thank you!
The only one I’m struggling to find is the timing chain tensioner gasket. I’m guessing the permatex wouldn’t work here? I’ll check Toyotas website to see if I can get one there.

 

What a great resource, thank you!