2010 Prius, Head gasket replacement. Re-ring pistons/ hone cylinders without pulling engine?

I am in the same situation on my 2010 Prius. Did you have any issues with the new rings seating? Did you just use a flexible ball hone on the walls to add some cross-hatch again? Did this correct your oil consumption or improve it significantly?
Thanks,
Chris

 

Virtually impossible. I am currently working on my 2010 Gen3 with HG, pistons, rings etc replacement. The problem is that the upper oil pan needs to be removed to get access to the rods of cyl4, but it is also the lower part that attaches to the transmission. You definitely need to remove the engine from the bay to get to the pistons.

Also it does not make sense to do it inside the bay -- there are tons of cleaning work you need to do that require flipping the block up/down and sideways. Doing it in the bay will result in a lousy job. Also you want to get the rear main seal replaced while doing the work.

 

^^^This.

 

I'm not sure what your current stage is, but I'm in the same process. Here are some tips about the work.

1. Get the head resurfaced and possibly the block redecked. At least take a measure of warpage. The warpage limit of the 2ZR is 0.05mm/0.00197in for both the head and block. The resurface/redeck can be done at home with sandpaper and glass.(a lot of youtube videos show how to)
2. You will need to get some tools including a ring plier, a ring compressor, and some 12pt sockets. The connecting rod bolts need 10mm 12pt socket and the flywheel bolts need 14mm 12pt sockets. Also I'm not sure if you are doing a more extensive head service, but at least I'm going to replace the valve stem seals and take a look at the valve seats. (the gasket set that I bought came with the valve stem seals). To do this you need a valve spring compressor and a stem seal installer. All those tools are not expensive though. The TSB also calls for a ridge reamer to remove the carbon from the top of the cylinders, but I feel it's optional.
3. You don't need to remove the lower oil pan from the upper. If you do then you probably want to replace the lower pan as it's only a $25 parts. I opted to replace the lower oil pan because cleaning the mating surface is really a PITA and when I removed it from the upper pan, I had to pry really hard that warped the mating surface.
4. I would recommend getting a new timing chain set if your engine mileage is high. I bought a Mitsumo set from amazon for about $80 and I compared the new chain to the old and found the old chain was stretched about 0.5mm or so, with about 237k on the clock.

 

Upper oil pan can be removed in vivo. Rods released and pistons through top. Soak in Berrymans gallon paint can. No need for heat … deep well socket and rubber mallet. Reuse rings and bearings (bearings usually look brand new). Replace parts exactly where they were removed from including direction for best results. Enjoy next 250k.

 

I think if it consume oil and the cylinder wall is toated, then get complet short block is the best solution.

 

So how do you get to the bolts behind the damper that also hold the
upper oil pan to the block?

 

Apology for delay. I’m not understanding the question. Upper damper?

All bolts are accessible without any specialty tool or socket needed.

 

Not "upper" damper, behind the damper.
From my understanding from reading what those that have replaced the oil pan, there
are bolt behind the damner you need to remove to get the main oil pan off.
And you can't do that unless you pull the engine.

I have not seen any photo's of the metal AND aluminum oil pans off while the engine
is still bolted to he CVTransaxel....

 

See here.

 

That's the first time I've see that. Maybe it's just easier and mor cost effective
to replace the whole short block.
Hopefully, the rear mail seal won't leak!