If the engine rattles violently for 10 seconds when first started, the head gasket is likely failing. Pro Tip: Budget for "Day One" Maintenance

Even if the car looks perfect, set aside in your head. This covers a potential battery cell replacement, a fresh set of low-rolling-resistance tires, and a thorough cleaning of the hybrid cooling system.

The "tank." Incredibly reliable but prone to dashboard display failures and catalytic converter theft.

At 100k miles, a Prius needs more than just oil changes. Verify if the following have been done:

Generation 3 models (2010–2015) are known for burning oil once they cross 100k miles. Check the dipstick; if it’s bone dry, the previous owner may have caused engine damage. 2. Service History Milestones

On 2010–2015 models, the Exhaust Gas Recirculation (EGR) valve and cooler clog with soot, which can eventually lead to a blown head gasket.