2013 Prius C Engine vs Head Gasket Replacement

Car Information:
- 2013 Prius C One
- Original Owner = Me
- Mileage= ~ 203K

Current State:

• A few weeks ago had a really violent start-up. (white smoke coming out of the exhaust and sounded like the engine was choking out).
• The next day, noticed a few drops under the car = Loose clamp(fixed it) and the overflow reservoir was at “low”(filled it)
• Last week check the overflow reservoir and it was half full(filled it)
  
• Currently, losing about 1/8th of the reservoir a day with zero leaks.

Conclusion: Head Gasket has a small leak path...

Question:
1. Engine vs head gasket replacement(Labor Cost is the same)?
2. Where can I get a reliable used engine?



Background:

• Overheat Light Came On While Driving(Drove another 10 Miles home after light Came on)
• Checked after stopping (Zero Coolant in Overflow Reservoir and leak in Hose found)
• Replaced Fluid, changed hose, and replaced the thermostat(shotgun replacement)
• Two weeks went by overheat light came on again = Temp sensor (error Code) and overflow reservoir was full.
• Replaced Temp Sensor water pump(Shotgun Replacement)
• One week passed by and the overheat light came on again. = Fan Not running and noticed coolant on the ICE located at a seam)
• Replaced Fan and cleaned seam to see if fluid would return. (it has not)

 

Yeah, rookie mistake for sure

 

Ordered and on the way to the dealership.

$3K USD Labor
$809 USD Engine

 

In my opinion, after 170,000 Replacing the temp sensor, thermostat, and water pump for no other reason than "planned obsolescence". Curious as to why Toyota doesn't have this as part of their maintenance timeline rather than allowing these parts to run to failure before replacement?

 

Replaced thermostat, water pump, temp sensor and fan. It was strange that they all failed.