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

The labor required to pull the engine and re-ring it correctly is less then the labor you will waste trying to re-ring it from the bottom, only to have to pull the engine anyway. It is possible to have the engine out by itself from the top in just a few hours. Pull the engine and rebuild it now, before the head gasket fails and the engine hydro-locks or hand grenades.

 

The oil pan has two parts. And to remove the 2nd part to get to the connecting rods, you must
remove the engine.
The pistons are installed and removed from the top. The crankshaft is in the way that's
why you can't remove them from the bottom.
I am not sure if you can still get the rings because they updated the rings and pistons late 2014 it is believed.
I imagine you could remove the pistons with rods and soak them in solvent to remove the carbon build up,
thus freeing the rings. Will the rings be as "springy" as when new? Probably not. But you might be able to
go another 100,000 or 200,000 miles on it before they get gummed up again. Depending on how often you
change the oil and if you use any engine cleaner.
But it seem to me that if you are going to go that far, spend the little extra money and get the 2015 model
pistons and rings. I believe you have to heat up the piston/rod assembly to remove the wrist pin. Though I
seem to remember 1 or 2 people saying they didn't have to do that. So I do not know.

Toyota has an engine rebuilt gasket set. It's probably the best one out there. But there are others.

 

Pull the engine, rebuild including the head, clean everything and install the Toyota gasket set. The head and intake will be carboned up and you will want new valve seals as they can contribute to oil consumption. A 2012-15 intake would be an improvement as well as a catch can. Then change the oil at 1k miles and every 5k thereafter. Another 100k-150k miles should be the result. Excluding the brake booster and batteries at a minimum. Some would change the radiator fans while the access was good.

 

I’d second @ASRDogman : if you’re doing the rings, best to swap to the revised pistons and rings. They were introduced partway through model year 2014. The pistons have to change too because the revised rings are not compatible with the old pistons. The revision was apparently to reduce oil consumption problems that started cropping up with the older (lower friction?) rings.

attached TSB has lots of info on the rebuild, and all the part no’s.

 

The best advice is in a red box several times throughout the procedure. Plus it applies to major omissions like the head in an older engine.

 

Depends on if the owner is a DIY that can clean intake manifolds. The newer intake design may not be an improvement. The old design has straight passages (instead of the tournament design) and is easier to clean with pipe brushes.

I agree that an OCC is useful for improving performance and extending engine life.

 

Pull the engine

 

So the oil consumption is from carbon build up on the pistons and not blow by past the rings?

 

As I understand the problem, the rings freeze up and cause uneven wear on the cylinder walls. That causes oil to get into the cylinder and increased pressure pushes oil through the pcv system. One Toyota mechanic suggests overfilling oil aggravates the condition. Once wear is excessive, rehoning won't do it. So the mechanic or ideally the engine rebuilding machine shop has to carefully inspect the cylinder walls. If uneven wear is present, the block must be replaced. While Toyota initially did replace pistons and rings under warranty for 2010-14 excessive wear victims, their practice now is to find a better engine or use a new short block.

Remember Toyota was providing warranty piston and rings on engines with less than 60,000 miles, not engines with two or three times that number. In reality few engines start burning oil excessively until well past 100,000 miles. My 2012 started around 150,000. Given that most people don't repair it immediately, excessive blowby carbons up everything through the pcv and egr systems, followed by clogged egrs and or blown head gaskets. Around here the discussion is often "what came first, the chicken or the egg?" Doesn't matter if your chicken is gone.

In a similar manner, a dealer head gasket job for these engines is usually not recommended because the job could easily escalate to a new short block rebuild, depending on conditions found after the engine tear down. Many dealers would rather swap a "low" mile used engine before committing to a head gasket job on these engines. As a result most customers find independent shops for head gaskets or rebuilds. With good results if the mechanic verifies each step of the way.

 

Thank you for all your info!

I'll just assume with me and 280k with oil burning issues and a blown HG that my cylinder walls are unevenly warn and a simple de-carbon soak for my piston and rings aren't going to be a miracle cure

 

Assume???? A dangerous practice!

There is a special tool to measure the cylinder walls to determine if they are still round and not oval.
Not sure what it would cost, but a machine shop could do that.
And if needed they could bore it out and you'd have to use the next size pistons and rings,
if Toyota, or aftermarket, make them.

Unless you've over heated the engine, the cylinder walls are likely fine.

 

lol is that you Miss Goodknow my 3rd grade teacher?

I guess assume was a poor choice of words. For whatever reason around here I'm limited by mechanics that will even take on that kind of work. Plus most of them are backed up for months. I only saw the overheat light once a couple of weeks ago for a second. After that I added more fluid that was lost. I haven't really driven the car at all since for fear of bending a rod.

 

The pistons and ring are different for the 2015.
Someone ordered just the new rings. But they were to big to fit on the 2010-13 pistons.
I believe the grooves in the updated pistons are wider, and the top is designed differently.
Also, the oil holes are larger. At least that is what he was saying, and he ordered the new pistons...

Bummer about the bracket! I hate crap like that, so simple, but deadly!

I'm glad you were able to get it all back together and running. I hope it lasts hundreds of thousands of miles!

Why didn't you install and OCC when you had the engine out? That would have kept most of the
oil out of intake, and engine. Just wondering.

 

Nice work

 

That’s a saga!

Never done anything like this, but it occurs to me, if you’ve got the older pistons, just swapping in a new set of (old style) rings, you’d have an easier job, and still be good for at least 100k.

also, any thoughts on drilling out the oil passages on the pistons, slightly enlarge them?

 

If you drill the pistons, you'll to take them off, and balance them.
In theory, they should all be even if you use the same drill size for all.

 

One might think bigger holes equal less resistance for piston movement so..why Toyota made them too small? Just asking. They were not born yesterday