How to Replace the Thermostat — 2020-2025 Hyundai Sonata

Replacing the thermostat on a 2020-2025 Hyundai Sonata is crucial if you're experiencing engine overheating, poor heater performance, or erratic temperature gauge readings. This DIY repair can save you significant labor costs, with parts costing between $30-$60 compared to a shop bill of $150-$250. With the right tools and this guide, most DIYers can tackle this job confidently in a couple of hours. DIY Cost: $30-$60 | Shop Cost: $150-$250

You’re done. Clear any stored codes with your scanner and complete a normal drive cycle so the vehicle’s readiness monitors reset.

If the code returns, the root cause likely wasn’t the part you replaced — go back through the diagnostic steps before swapping anything else.