Gen #3 engine head gasket blew at 254,000 miles and engine hydro-locked

well done, you've taken care of the 2010 weak point, should be good for another 100k.

all the best!

 

I hope the EGR was cleaned out.

 

And the intake manifold.

 

And changed ATF

 

I drain my catch can at oil change interval. It only accumulates 5-6 ounces of gunk in 5k miles.

 

That gets repeated ad nauseam here and I don't believe I've ever seen anyone yet connect the dots to show it. It could be true? It has that truthiness quality, where it seems to make a pretty good story, as long as nobody asks the obvious questions, like (1) how much cylinder temperature difference does the EGR make, and (2) how much temperature difference can the gasket handle?

The answer to (1) is "well, clearly enough difference to affect NOx emissions, since that's what the EGR's there for", but whether that's anywhere near a temperature that would explain gasket failure, that's a question that's been ducked a lot of times in these forums.

Even if there is an established correlation between EGR clogging and gasket failure (and even there I've never seen anyone offer numbers and a p value yet), overall increased temperature is only one of the possible mechanisms that could link one to the other. Until somebody does the work to find out (which might very well have happened already and be in a library somewhere no PriusChatter has looked yet), we're just kind of spitballing.

If you've actually got new information to contribute to showing that, it would be great to have that brought to the forum. But sometimes it's pretty easy to catch yourself repeating things you've seen repeated elsewhere, and they just stay in circulation without ever getting any better established.

 

If someone cares fervently enough about some truth, perhaps it's best they search it out.

 

Does searching w/Siri or Alexa count as a caring fervently also?

 

No doubt you made the right move to save your car. Somehow I doubt a headgasket would have worked with two holes in the side of the engine.

As far as the egr goes, I think frequent oil changes while the engine is clean will keep it that way longer, even with known piston ring issues. Reduced oil consumption will keep the oil out of the exhaust, which in turn will reduce the gunk in the egr.

I know my egr cooler first clogged up at seven years 200,000 miles. Recently it was inspected and it is 90% clogged again. This time in two years 44,000 miles. Of course there is more oil burning now.

I find myself agreeing with Chapman on the science behind clogged egrs causing head gasket fails. We do know the gunk flows freely through the egr into the heads. Clearly before the egr is clogged. Once the cylinders are gunked up I am sure there are consequences like knocking and preignition which absolutely causes stresses. It takes an event for the knock sensor to react. I also know that a low hv battery on a high mile engine can sometimes cause a knock on low speed acceleration, probably because the cylinders are caked up. And it is definite that small coolant leaks into the cylinder can go on for months with little impact but its certainly a game of engine russian roulette that sometimes blows a hole through the block(head).

Then there is the fact that Toyota rerouted the egr intake to downstream of the catalytic converter by the fourth generation. Let the cat clean up unburned oil and fuel before dumping it back into the cylinders via the egr. Of course the rings and pistons were upgraded late in the gen3 run. Reduce oil burning and fuel blow-by. Makes sense. Almost like science at work.

I wonder why some clever machinist has not come up with an egr retrofit kit that pipes the system from behind the cat? Sell it with a protection cage and a cheap aftermarket cat that fits in the space.

 

Wait a minute, Mendel was accused of being insane for saying the same thing yesterday. Or was it insanity for him to conclude with that. Either way, you catch my drift.

 

Usual way this works is a person claiming to know something is responsible for supporting the claim.

If your Uncle Fred tells you the world is being run by satanic cannibals and you're unconvinced, he will probably also say it's your job to go down the whole rabbit hole and tell him what you find. And sure, if your time is limitless and free, and you can't think of anything else to do with it....

 

Cmon, Toyota calls that normal.

Seriously though, with 440k miles on the odo, not bad.