Help Identifying a Leak (Engine Block Coolant Drain Plug?)

Leaks are......'interesting' .... at least to me.

Submariner's rule:
If you find it?
It's a leak.

If it finds you?
It's flooding.

So.....
What's 'leaking?"
Oil?
Coolant?
Rain water?
Transaxle Fluid?

How much are we talking about??
It is a weep? seep? drip? dribble?

They each have individual meanings.

Where is the car parked?
In a garage?
Driveway?
An 8oz cup of fluid is....a LOT.
Spill a full cup of coffee onto your kitchen floor and you will know what you know....

What's in YOUR gargae?
Driveway?

Deets!!!!
Are you the original owner?
Does the phrase "EGR cooler" mean anything to you?
What's the coolant level? Oil? Coffee carafe?
Has the bottom end of the engine been replaced (yet?)
Maintenance history?

If you're the 2nd (or 3rd....4th...etc...) owner then you must presume that 'your car' has a 'history.'
This is nothing to be ashamed of.
We all have 'histories.'

PRESUME that YOUR car has its original head gasket, plugs and coil packs, oil filter, and that the EGR circuit hasn't been cleaned.
PRESUME that this is a factory-maintained vehicle, and that you're 80,000 miles past the extended factory warranty period - which means (according to Toyota's philosophy) that they've met their obligation to produce a 'good' car.

Me?
I'd start looking at fluid levels more often and I'd replace the plugs IMMEDIATELY - not because the plugs are wrecked but rather to give you the opportunity to look at the plugs and maybe invest $50 in a borescope, and maybe look into the holes.

Also...
If you start to get the "Prius Death Rattle" ......STOP DRIVING IMMEDIATELY.
You will not have to wonder if this is occurring.

Good Luck!!!

 

OK.
So....

1. I fix telephones for a living. NOT cars.

2. If your car was 'dealer maintained' by a scrupulously honest and thorough dealer, then it was only marginally maintained - AT BEST.
I do not say this because I think that dealerships are less than honest (although they 'sometimes' are!)
I say this because dealerships hue to a 10,000 mile OCI - or oil change interval which is insufficient to the task.
If you want to keep 'stuff' out of your intake and oil you need to change fluids and filters more often than every 10,000 miles
Your car has (according to your OP) more than 200,000 miles - which means than in 'human' years it is more than 90 years old.

You have to treat cars that are that old a little differently.
Toyota DID their part.
So may have their dealers.


TL ; DR
IF you are doing YOUR part (checking fluids) every 30 days or 1000 miles and the levels are not dropping significantly (measurably) then you're doing your bit.
@ 'Bottom end'
No. It would appear that your engine in OK for now.
MAYBE even REALLY OK. - like you will go 300,000 miles.
Unless there are puddles and you're losing fluids - the photos indicate 'weeps' or 'seepage' instead of leaks.
G3 Priuses are known for having a timing chain gasket leak - which is really just a seepage.
Even IF it's an 'oil leak' and if you're checking your oil every 1000 miles or 30 days per the maintenance manual AND you're keeping your oil level between the dots then you're golden!!

What ALL OF this means to you is that the stuff in your photos likely a 'seepage' - and NOT a real 'leak.'

Think of this like your own body.
You have about a gallon and a half of blood volume...or nearly 200 fluid ounces.
We are encouraged to donate a pint of blood every now and then (3 times a year more or less.)
It's not a perfect analogy because oil and blood are different and Priuses have an insufficient 'blood' volume (about a gallon, including the filter)
A fluid pint is two cups of blood - which YOU WOULD FIND - even in an unpaved driveway.

My point is....if you're 'bleeding' then it means you may not necessarily have to go to the hospital IF you KNOW where and why.
'Sometimes' - 90-year-old humans 'lose fluids' because they're.......90 years old.
We don't take then to a hospital for cuts and bruises.

Get that checked out!
Again - I'm just some internet rando - and I am an electronics technician - and NOT a doctor.
FIX YOU FIRST - then worry about the &%$#! car.
My own biases lean towards faith-based counseling - but that is MY bias.
Military and Law enforcement are over-represented in self harm as a result of clinical depression - so if you are perhaps a member of one of those communities then this warrants immediate and thorough attention if it is 'life style affecting' - most especially because those communities lean away from 'feeling sorry for themselves."
There is a cultural bias in this nation against mental illness which is unfortunate because we often laud cancer or traumatic injury victims as 'courageous.'
Depression that affects your day to day life IS a mental condition just as a common cold that affects your day to day life is a physical condition.

Six weeks of cold symptoms (more or less) warrants a visit to a medical professional.
-jest sayin....

Good Luck!!

 

If the leak is oily it’s not coming from engine block’s coolant drain. It’ll only be leaking coolant.

I’ve been to that; it’s a smallish bolt and IIRC a socket head cap screw, has an Allen-Key style pocket. It’s up high on the block, ‘round back, near passenger end of engine (aka front of engine). There’s a small spigot protruding, directly below it.

To “drain the block” you loosen that bolt and coolant flows from the spigot. That block draining yields less than 1/4 cup coolant, not really worth the effort.