Was the EGR system service done as regular maintenance at dealers?

no, they do not. it's not in the manual, most dealers don't even know what it is, and the ones that do only change out the cooler
al that being said, it is possible that a prior owner could have requested it, or done it themselves.

or they could be selling it because of early warning signs of head gasket failure, or massive oil burning

 

I don't think there is anything in the Warranty and Maintenance Guide entailing any EGR work at any mileage.

If you bring a scan tool, or a laptop with Techstream, to a test drive (and the seller doesn't object to you connecting it), you can both check for any existing trouble codes (an essential step, IMO), and also pull up the most recent EGR flow monitor test result, which will tell you something. (We've had enough data reported now to start recognizing numbers that look recently cleaned and numbers that don't.)

 

I'd just assume the EGR circuit (including intake manifold) is in need of cleaning, soon. More info in my signature.

 

you would follow mendel’s post #4 and do it carefully. In your shoes, I’d get a regular gasser and not have to clean anything, unless the Prius bug bit ya and there’s no cure.

 

Service on time at the dealer really means nothing when it come to theses cars.
Traction battery could go out at anytime................ and a possible head gasket failure.... I know I've replaced everything except the entire engine. If you think you really need one of these get a 2015 or newer.
Plus the inverter and brakes will go out. possible covered but can be a huge hassle if out of town or only have one car.

 

My 2013 failures
Head gasket
Inverter
Traction battery
Brake System
Water pump

 

shocked the 12v bat ain’t on the list

 

OK...... and the 12 volt batteryyyyyyyy

 

Don't buy the car if you plan on keeping it a long time...............................................

 

The 2015 gen3s had a new piston and piston ring design. That reduces or eliminates excessive oil consumption common in the 2010-2014 Prii. The 2012 intake solved little. The reality is many significant 1.8L engine design changes occurred in the 2016 gen4s. Most are clear responses to gen3 mistakes.

Toyota acknowledges the oil consumption, brake booster and inverter design flaws of the 2010-2015 gen3 Prii. Only the oil consumption low tension clogging piston rings were fixed in 2015 gen3s.

Other problems that are also wallet busters include a poor egr design (fixed in gen4), intake manifolds that accumulate large amounts of oil, and of course, the expected hv battery failures.

Most new gen3 buyers had a relatively good ride through 150k miles but the long haulers or subsequent used buyers suffer. Many say more frequent 5k mile oil changes and 75k-100k egr cooler cleanouts "may" help a good engine stay that way but used buyers will have preexisting conditions that only major surgery can restore.

Buying a used gen3 is not a good idea from a reliability or cost of ownership standpoint.

 

In a general sense, absolutely. But there's nothing unusual about this in the Prius context.

Virtually any car with an aluminum engine, upon suffering a significant failure of the water pump, will overheat and stress its head gasket(s).

 

And there are thousands of gen3's out there with 200k+ that never had any problem....everyone here assumes they you WILL have one of these problems.....and you may have one or more in time. But it's not as sure thing as posters here will have you believe.

 

I can't disagree with that.

What catches me is how much care and planning is (frequently) taken in selecting a 10+ year old cars. It's often on a level that would be appropriate for a 4-5 year old car that still has quite a ways to go.

...then I remind myself that the used car market is desperately overheated and people are paying bonkers money for old heaps.

 

Comes of the car becoming mainstream. Buyers of the first Prius generations were definite early-adopter personalities, and even more so the buyers of the first used Prii, and later most especially the first buyers of used beyond-warranty Prii, who very commonly joined communities like this one proactively in the hope of staying ahead of predicted nightmare expenses that turned out, overall, not to be so nightmarish.

But something changed by the late years of Gen 2 and then Gen 3: millions of people were just buying the things like they're cars. Of those millions, many who have not faced big expenses have never had any reason to discover or visit PriusChat. But people encountering expensive issues often do look us up and post here. So after a while, if you go by posts on PriusChat, you start to think that you're bound to have one of the reported big ticket issues, or even that you're bound to collect the whole set!

 

I've for many years thought of 10+ year old cars as having quite a ways to go. I'm not sure to what decade I would point as when 10+ became the new 4–5, but I sort of thought that already happened.