Is Head Gasket failure common in Gen 3?

depends on how you define common, i think not.

first your egr clogs, then your head gasket blows if you don't do something about keeping the egr clean
nothing else fails, but a head gasket is not simple like in some cars, most require a new/used engine

2014 and 15 have improved piston rings which (may) help

 

I stand in awe of that.

 

blown head gasket after ego clogging =

 

I'd second the need to get on EGR cleaning early on, ditto for intake manifold cleaning and an Oil Catch Can install on the PCV (Positive Crankcase Ventilation) circuit, to prevent the intake manifold promptly gooping up again.

When head gasket fails, depending how it fails, it might fill a cylinder with coolant, which can bend a piston rod.

Also, head gasket replacement can be an expensive gamble. It's a lot of labour, often simpler to drop in a low-mileage engine from a wreck. That can be a crap shoot too.

 

Definitely best to get on the egr circuit early.

I think we just saved a 2011 CT200h out here a couple of weekends ago by doing that at 159k miles.

I’d pair the job with either the spark plugs at 120k miles or the engine coolant at 100k miles.

I did round #1 of the egr circuit at around 120 k miles and again at 175 k miles and glad I did.

Good preventative maintenance item.

 

For the reasons described above, head gasket failure is more common in Gen3 Prius than it is in Gen2 Prius...

 

The rod is about to emerge from the block.

Find a new engine and replace it don’t try to do the head gasket in this one.

It’ll save you some grief if you are determined this is the cat for you.

 

BUT,, how can these 'reasons' and 'Good prevent. maintenance' claims be verified?

My '11 at 182k miles is going strong. My bank courier buddies' Gen3's are going strong at +400k and 600k miles.
All without dikin with the EGR circuit. Maybe mostly highway miles helps keep this circuit flowing? Who knows?

If it is life or death, why is it not officially mentioned within Toyota's long term maintenance schedule?

I'm just asking, Technically Speaking, how is a choked down EGR circuit going to lessen the life of a head gasket?

 

it's all in danlatu's thread.

 

He’s read it several times.

But maybe soon he’ll come around.

 

Does a cat have whiskers?

 

as for why toyota doesn't have it in their long term maintenance schedule, there's a lot of things like throttle body cleaning, tranny fluid, etc. it's called 'marketing'. as long as it doesn't blow up under warranty, everybody's happy.

 

Forums like this are where you find the shallow graves .

Once you find them, knowledge is power.

 

There is a Technical Service Bulletin for the Exhaust Gas Recirculation, but requires advanced symptoms and/or a code, and by that time...

 

I'm thinking, maybe the restricted EGR folks used low quality gas? I remember first reports of clogged EGR came from Europe. Not sure why.

I didn't crack the EGR cooler yet, will do it next spring or summer, But I did check the EGR pipe condition at 70,000 miles and there was only light coating. I use only quality brand gas.

 

As many of the earliest threads on PriusChat will vouch for, the Gen1 and Gen2 was designed to run on lowest grade gas. I assume that's the same for Gen3...

As for using higher quality gas, my understanding of what that means is they add extra additives to boost octane, as well as other stuff. But how that higher octane / additives would help prevent the oil in the crankcase from gumming up EGR system to the point your system is cleaner and you're at less of a risk for a blown head gasket is beyond my understanding. Maybe someone will add to this thread more detail about how that would work? Perhaps the detergents in higher grade gas keeps the intake manifold and ports cleaner?

 

Maybe nothing to see here?

 

I use top tier gas and the deposits form.

All the additives do is extend the time it takes for the deposits to occur. I also add BG Products 44k every year (which is essentially highly concentrated Techron) too.

So +1 to nothing to see here.