Gen 3 Valve Seals - The Definitive Source of Oil Burning?

There has been non update, yet, of the few that have replaced there head gaskets and
valve guide seal at the same time.
I guess they have not put enough mileage on it yet.
I personally believe the seals are the biggest cause from experience with other engines.

I think we are all waiting to hear an update...

 

Oil get sucked into the cylinder then burned.
The seals get hard and brittle. Once they get hard, you can't soften them up.
You just have to replace them.

 

I have water front property in south Florida really cheap if you're interested.....

You are free to try whatever you want.

 

The valves and the heads are machined to perfect tolerance to seal. It’s not about being soft or hard; it’s not some kind of gasket or soft material.

MAYBE you can have some cooked-on deposits which prevent perfect seal. But considering the temperatures and pressure that cooks that stuff on, no magic oil is going to get rid of it.

 

Have you tried the BP treatment of 44K, EPR, and and MOA? They helped alleviate some of my 2010's oil burning after the first run, and I use the EPR/MOA with every oil change now, the 44K once a year.

 

Good to hear it is still working .

How many miles you up to now?

 

I'm in the market for a Gen 3 Prius. It appears the Gen 3 years 2010-2011 are the worst impacted years for poor seals/blown head gasket issue.

Although it sounds like Gen 3 years 2012-2015 have less of this issue occurring, can anyone confirm if this issue was completely resolved for Gen 3 years 2012-2015 or just occurs less frequently?

 

I doubt there's much difference. Sometime thru model year 2014 the pistons and rings were revised; that's all I've heard/gleaned. Oh, and EGR valve, and intake manifold had revs, at some point, but don't see that changing oil consumption.

 

I haven't driven much at all this year b/c of Covid, but I'm around 162k miles. I might switch over to 5W-30 oil at my next change though, as last time I checked it seemed like the burning was picking up again.

 

Toyota thinks it’s pistons and rings, if you look up TSB168 and 169.

 

Valve stem seals are a soft material, and replaceable.

 

If you watched the whole video, he also talked about the oil.
He does make a good point for the OIL ring loosing tension. They are weaker so
there is less pressure on the cylinder walls, which reduces friction and theorotically, improves
fuel economy. This does make sense....except, today's cars use synthetic oil.
It doesn't break down like conventional oil to cause the clogging. Yes, if you leave it in
long enough, it will. But it's also designed to go 10,000 miles. The question is, is the filter?

I do know for a fact, and experience, that valve guide seals fail and do allow oil to be sucked through
the intake side.
With weaker piston rings, and the egr cooler clogging up, and oil getting sucked in from the intake,
which will produce a more "oily" exhaust to go through the cooler, it will cause more back pressure than normal and cause the head gasket to fail sooner.

Will 5000 mile oil/filter changes stop, or slow this? Possibly. It certainly won't hurt, except in your wallet.
Maybe split the difference at 7500....

I also watched another video of the different viscousity of oil and what your "should" use, and why.


Here are the videos:

 

If you look at Fuelly mpg for various 3rd gen model year, there’s a slight but definite dip in mpg for 2015; I’d guess due to the higher tension piston rings.

Toyota Prius MPG - Actual MPG from 8,314 Toyota Prius owners

(^ Actually 2010 is a close second.)
(And 2016 onward make a BIG improvement.)

Toyota wanted to eke out a slight mpg improvement, for various reasons, presumably monetary. Similar story with the 10K oil change intervals.

And their customers have to deal with the oil consumption.

 

It is an interesting video and makes me wonder where my engine is at. The first time I did the BG treatment with 44K, MOA, and EPR my oil consumption dropped dramatically. I've done it with every 5K oil change since. But now, a few years later, it seems to be back to burning around 1qt every 3000 miles. If I've driving through hills a lot it burns like there's no tomorrow. So if it was indeed the rings previously, it might be something else now like the valve seals or worn chamber walls. I just changed the oil last week so I'll see if it's changed or if it's just how my car is now.