NEWBIE -- General ? -- Head Gasket -- Prius V -- Model Years?

I know way more about Gen2 than Gen3 but my understanding is that by 2014 they redid where the EGR system grabs the exhaust gasses and eliminated the high MPG piston rings that burn oil once they get old.

 

No. The EGR system had a revision to the valve, I believe newer one is slightly taller, but that's all. The EGR gasses for all years of 3rd gen Prius and Prius v are taken upstream of the catalytic converter.

Gen 4 Prius revised the EGR intake to the downstream side of the Cat, and also seems to have increased cross-sectional area of the components, roughly doubling? And that seems to have done the trick, which is good for Gen 4 owners, not so much for Gen 3.

The piston rings were revised, mid-year 2014 for Prius, and sometime similar for Prius v. A number of people (here and on YouTube, elsewhere) are saying the EGR carbon accumulations are at least in part due to oil burning. I don't think that's the case. I do know our 2010 (with the older style piston rings) is not burning any oil as yet, but the EGR system, when I cleaned it 5 years back around 70K kms, was getting carbon build-up. Not a lot, but seemed about on par with other (higher miles) reports here.

I should be revisiting ours soon, around 96K. Just waiting for a garage space heater to be delivered.

Bottom line, at least for me: if you've got a 3rd gen Prius (2010 through 2015), or any year of Prius v, and you want to avoid head gasket failure, keep on top of EGR (including intake manifold) cleaning. A easygoing schedule would be to do at the same time as engine coolant: 100k miles, and every 50k thereafter. My 2 cents: clean it every 50k, from the outset.

 

I can testify that after an initial complete cleaning of the EGR cooler, a single can of brake cleaner will rinse the cooler clean at 30k miles.