I checked just now with Amayama. It might be old stock, but anyway: Old ring set: New ring set plus pistons: They just happened to be lowest price for one option through UAE, and the other through Japan, so that works out nicely, to see the difference. Geez, i could revive my block, albeit with just the old rings, for under a hundred CDN. And just swapping rings is easier I think. You'd want to clean up the pistons, but still a lot less involved?
I wasn't commenting on dealer behavior, just on the part I quoted, about being "aware that a dirty EGR valve is causing the failure." If that turns out to be true, then we can be "aware" of it. Until then, it's just something that gets said here a bunch.
Agree there were significant changes throughout the engine including the egr. The egr's primary purpose is to lower emissions and improve mpg. Obviously if its a flawed design it does not reliably achieve those goals. Plus it throws codes that cost about $1,000 to fix by the book. There are aftermarket replacement rings available for the 2010-14 engines. If the originals are replaced and the oil is changed at 5k intervals, another 100k-150k miles should be possible without significant oil burning and related issues like clogged cats, increased egr issues and intake manifold fouling. My bottom line is the gen3 system has flaws that were resolved in the gen4. A partial overview here. A gen3 engine rebuild with rings would be my choice over a simple head gasket replacement. In today's world with inflated car prices, $3,500 for an independent rebuild would be my goal.
I don't believe Toyota will be buying from ebay, or anyone else. They might have had some in stock, or maybe Toyota still has them available.... Bottom line is: Is the customer happy with the work performed and with the price? If the customer is, the rest is a mute point.
Thanks for finding that link. I was sure I had seen a photo somewhere of that updated "tournament" routing of the manifold EGR passages, but couldn't lay my hands on it. I've been getting lazy with my collection of the New Car Features manual. I have them complete on paper for Gen 1 and Gen 2, and have portions of Gen 3's downloaded but not the whole thing, and haven't gotten around to signing in to look seriously at Gen 4's yet. As far as third-party sources go, that one from marklines looks pretty good. The best part? They're a non-US firm, so it explains the Japan/Europe version of the cooling system, with that electric "flow shutting valve" that you can't find in the US parts catalog because we don't get it here. I'm not sure what they say about it is quite right—it doesn't square with their own diagram, and it looks to me like the diagram is right—but it's the closest thing to an explanation yet, short of signing in to TIS and reading the NCF. (Certainly "previous Prius models coolant did not flow to the heater during warming" is balderdash.) Reminds me of a whole thread over the summer that was filled with guesses about how that system worked because nobody had bothered to look it up, and it took two pages of the thread just to agree on which direction the coolant goes! I see also they added a little stream of coolant that goes right through the EGR valve itself. Probably makes no difference for 99.9% of people, but might prevent the odd freak occurrence like when ozmatt drove hard up a long hill in 40℃ weather and melted a track right through the stop in the plastic rotor.
This is a very bad idea changing motor oil at 10,000 mile intervals. Oil is cheap, motors are expensive.
That interval is recommended for Prius when using full synthetic... And yes I do slightly agree that 10K is a bit high and change mine closer to 8K miles of mostly highway driving up and down the west coast. At first I changed every 5K miles but that had me changing oil after every road trip, which was resolved due to synthetic oil running cleaner way longer than regular oil. These engines run so clean in the first place that the 10K mile interval with full synthetic seems reasonable to me.
Black stone analysis of full synthetic oil in a Prius at 10k oil change interval shows it to be fine. But you're free to spend more money on oil as you see fit.