New to me prius maintenance

Does this one have a new head gasket? How frequently oil was changed based on maintenance history (5K or 10K intervals)?

 

You know its service history? Private sale or?

keep an eye on the engine coolant level in the reservoir.

 

Make sure you are regularly checking the oil.

Replace transmission fluid.

Replace engine coolant and inverter coolant.

Entire EGR system cleaning service including the intake manifold.

Spark plugs? Take note that these are a VERY commonly counterfeit item, but the OEM's can easily go well over 200K.

Mentally prepare for the head gasket to blow within the next 50k miles.

Get yourself a OBD2 bluetooth dongle so you can monitor codes, temps, battery health, etc.

 

With 200k miles, and so far no mention of EGR cleaning, there's a decent chance it's got a stop-leak product in the coolant, to hold the head gasket together.

Again, private seller, dealership, or?

^ Always worthwhile, but considering you're at 200K, maybe just something to study up on, and concentrate on head gasket assesment:

 

I would do nothing for a while. Odds are good there’s a stop-leak product in the coolant. This will effectively arrest head gasket leaks, for a while, which will make diagnosis of head gasket leaks nigh impossible. For a few months.

it tends to wear off, and leaking head gasket symptoms return, typically coolant leaking into cylinders, usually starting with cylinder one (at passenger side of engine). Symptom is typically engine shaking on cold starts, after sitting overnight.

if and when that occurs, a boroscope inspection of the cylinders will show coolant pooling atop piston, and unusually clean piston top. First thing in morning would be best time to inspect.

head gasket replacement, followed by full EGR and intake manifold (it has EGR passages), and you may be good. There’s still a chance a piston arm has slightly bent, the damper between engine and transaxle and engine has incurred damage, and/or cylinder walls have scuffing.

truth be told, it’d be prudent to just drive it a few months, and if symptoms arise, consider just selling at a loss, with full disclosure.

there’s an outside chance you’ve got the miracle 3rd Gen, but I wouldn’t count on it.

did the dealership make any mention of head gasket?

one thing you could take a peek at, to determine EGR degree of carbon-clogging: the pipe between EGR valve and intake manifold. It’s covered in video #16 here:

Nutz About Bolts Prius Maintenance Videos | PriusChat

 

Another thing: 3rd gens till partway through 2014 have “low tension” piston rings, which have proven extra suceptible to oil consumption . Your 2014 may or may not have these; would be good to know, a factor when deciding on a course. There is VIN at which the change occurred. @rjparker has the latest info on the VIN change.

 

Each factory has its own sequence number when the revised pistons and rings were used.

 

If you could get it done well and for a good price I'd say yes, but it'd be expensive to the point where you should just wait and hope you get lucky, but prepare yourself. Maybe even look around if there are hybrid specialty places near you that do 3rd gen HG's because ultimately it's not that big of a job for someone who does it often, but they'd probably laugh if you said you wanted it done preemptively.

 

Does this mean a small used car dealer? Or a Craigslist/Facebook seller?

How much oil does the engine burn in 5,000 miles?

Has the engine ever made a loud rattle sound when starting?

 

The battery may be part of the problem, but have the mechanic go through all the ordinary bits of the car.
Engine, brakes, tyres, filters, and etc

 

All these comments sound very negative.

You may have got one that was not driven hard and taken care of.

I would put a bottle of Cataclean in.
Then try the BG hybrid kit.

Have your egr system and intake manifold cleaned out completely.

Make sure to see it all clean and done.

Clean or get new MAF & MAP sensors.

Get new upstream A/F & downstream o2 sensors.

New spark plugs/ignition coils, maybe fuel injector cleaning.

Then disconnect the 12v battery for 10 minutes, after everything I said is done, you should see a minimum of 47mpg

Toss in a new air filter for good measure.

 

Yes a worn out hv battery will cause poor mileage.

A mechanic has to be experienced in Toyota hybrids or will often misdiagnose. It does not matter if they are great in conventional cars.

 

I have a 2012 Prius with a similar mileage to the OP with an unknown history, and am planning an EGR clean, but not planning a head gasket replacement. Should the head gasket be replaced even if there are no symptoms of trouble?

 

I would first check just the pipe between EGR valve and intake manifold, first, to get some idea of the rest of the EGR system. See video #16 here:

Nutz About Bolts Prius Maintenance Videos | PriusChat

I wouldn’t replace head gasket until you’ve got symptoms, typically harsh shake at cold-starts after sitting overnight (coolant leaks into cylinder overnight).

FWIW, if you’ve just acquired it, with 200k there’s a good chance a recently bought 3rd Gen has HG failure, possibly masked by stop leak.

 

"IF" you wanted to do the head gasket BEFORE it fails, that's okay.
That was my plan. I had planned on doing it the next weekend. But it had that
knock twice, then the coolant level went down slightly.... But it's done...