Resurface head and replace valve seals etc at time of headgasket replacement or not?

well, I finished the tear down.

Points to ponder:
-- there was some coolant in cyllinder 1 and 4, but not much. However, I had rotated the engine to TDC, which puts 1 and 4 at the top and thus any more coolant might have been forced out, at least of cylinder 1, which is compression cycle, right? The other is exhaust cycle, so a valve would have been open...... Coolant might have just drained into the cylinder from residual coolant in the head somewhere that leaked into the cylinder when I cracked the head loose.

-- My heads look a lot different than all the videos. All 4 piston tops are pretty clean, and the heads are nice looking too. Engine was not burning oil, had no issues. EGR cooler was not plugged.

-- I pulled one exhaust valve. It looked quite nice. I learned that I am not steady enough and my mits are too large to put valve keepers back together. To do 16 of them would drive me hysterical bonkers. I called the local head shop -- they are busy and would take 14 days to do my own heads. I am not interested in swapping to some other head, as my heads are near perfect. The owner of the shop was saying that in his experience, valve seals are not much of problem with Prius these days.

-- I did not see a clear point of leakage in my HG. But I did not run the engine much at all after the event.

I am contemplating just putting it back together with the Felpro HG and all the new seals from Toyota and see how it goes.....

 

My sentiments precisely. Honestly, the Prius timing chain looks like I could do it with one hand compared to a timing belt on a Subaru boxer. I used the "shop towel" trick that several of the videos demonstrate online to fasten the cam lobes in place. Worked nice AFAICT -- so getting the camshafts in should be easy enough. I used two egg cartons labeled for the lifters, rockers and caps, so they will go back to their respective original locations.

Now, I managed to damage one of the dowel pins that decided to stay with the head. Tried to remove it and just buggered it up. $1.71 from the local dealer, so no problem. And it made my wife happy that I cannot do anymore wrenching on the Prius until Easter is over. To the dealer Monday for that and the timing cover seal for the timing pully that is not included in the Toyota kit, per NutzandBolts video......

If it turns out that the exhaust heat recovery thing is the culprit, then so be it. How a leaking EGR cooler could trigger the exhaust heat recovery thing to fail is beyond my comprehension, but this whole sequence has an negative karma overtone to say the least, so anything is possible I guess.....

 

Well, decision to have heads checked by a good shop got made for me in a different way -- saw my eye doctor this AM and getting semi-urgent cataract surgery in AM. Soooo, I won't be able to wrench on the Prius for a week or so. Might as well take the heads to the shop. They say 4 days to surface and do leak down test. More if they have to do the valves.

But if I cannot work on the Prius, may as well spend the time and get it done right.

Shop owner noted that Prius valves do not "rotate" like some vehicles used to and still do in some instances. This means that in his opinion, you must do a complete regrind if you take the valves out to replace the seals, because they will have "seated" in to a particular position and in his opinion, even if they were not leaking, they will leak sooner or right away after just replacing the valve seals. He was of the opinion that if the leak test was OK, then leave the old valve stem seals alone.