Probably Head Gasket? What to Expect

While it’s not the EGR that’s causing the shake now, a carbon-clogged EGR, and clogged EGR passages in the intake manifold, is likely the cause of the head gasket failure.

if and when it’s resolved, do clean the aforementioned EGR components, to avoid a repeat. More info in my signature.

 

Get it fixed. Head gaskets are increasingly common on 2010-2014 Prii and are happening at lower miles as shown in your case. You want the head machined, new valve seals and a complete gasket set installed. It is very possible it could be burning oil because of a design flaw with the piston rings. The cars are good vehicles in most areas but you can expect a hybrid battery and brake booster by 150k miles on your ten year old car. Best thing is to fix the head gasket, hopefully for $2k, get a year of use until the market stabilizes and then trade for a newer vehicle.

 

You need at least a Head Gasket. Before you have your mechanic do the HG, ask what is your Oil Consumption? If you are consuming oil, you should consider the new engine route. With a new engine (or a used engine from a 2015 or later car), you will get the new oil control ring design, which will save headaches down the road.

And take @Mendel Leisk's advice. The EGR may be working fine, but you need to address the carbon clogged EGR Passages in the Intake Manifold. I am convinced these clogged passages caused your HG failure, and will lead to a second HG failure in 20k miles or less if not taken care of at the same time. It is not difficult to clean just the Intake Manifold passages, although a full cleanout of the EGR and EGR cooler would be worth adding to prevent more carbon buildup.

And change the oil with 0W-20 Synthetic every 5k or 6 months, not the 10k Toyota specifies. At 97k, The previous owner didn't drive it much. Chances are, it often went more than one year between oil changes. That is not good for any engine. All the more reason to consider a brand new engine.

 

For third gen, Toyota USA spec's 10K miles or 12 months, whichever comes first. OTOH, Toyota Canada spec's 8000 kilometers (roughly 5000 miles), or 6 months, whichever comes first.

This is a massive difference of opinion, kinda begs a few questions?

Further:

For second gen Toyota USA was 5K miles or 6 months. Canada the same.

For fourth gen, both Toyota USA and Canada are 10K miles (or 16K kms) or 12 months. With an engine essentially the same as 3rd gen.

All of this makes me very sceptical, as to how and why they set these intervals. I'll just keep plugging in fresh oil (and filter) every 6 months, per the Canadian 3rd gen schedule. And we're currently doing around 4K kms, yearly...

 

Even in the US its 5k mile oil changes IF you meet their "severe" standards which can be high speeds or excessive city stop and go. The official reason for 10k miles is reduced environmental impact through less use of oil.

The worst thing was giving new car buyers two free 10k mile changes until 25k miles. It set a pattern, a) go to the dealer for maintenance and b)10k miles with synthetic is fine. I remember most initially thought synthetic would stop normal engine wear. Maybe with 5k changes. Plus many drivers "forget" to change the oil once in awhile, especially since the maintenance minder is not set to 10k. So you may have a 15k-20k mile change occasionally. Add in the 2010-14 piston ring screw up and you have the recipe for disaster that we are seeing now.

It would not surprise me if Toyota saw the Priuschat gurus blaming head gaskets on egrs and decided to let that ride. Diversion from the "smoking gun" rings which should have been a worse class action than the brake booster. Of course safety issues are easier to win for the big legal firms.

 

Or you can do it yourself.......no head work just gaskets and new bolts....... $250.00
Did it to mine at 250.000 and it's still going @ 300,000......