255003C150 Hyundai / KIA THERMOSTAT ASSY, Price: 28.67$, Weight: 0.154kg

Engine Cooling Thermostat Assembly for Hyundai and Kia

This precision thermostat assembly keeps your engine at the correct working temperature, balancing warm-up speed and cooling capacity. It shortens cold starts, improves fuel economy, protects the head gasket, and keeps cabin heat steady on winter mornings ❄️.

Why this part is needed

Engines are designed to run in a narrow temperature window. This unit controls coolant flow so the motor reaches operating temp fast, then holds it there under load, traffic, or highway cruising.

How it works

Inside is a wax-pellet valve. When coolant warms, the wax expands and pushes the plunger, opening the path to the radiator. When coolant cools, the valve closes and routes flow through the bypass for quick heat-up. Many versions include an O-ring seal and housing for leak-free fitment .

What happens if it fails

Stuck closed: rapid overheating, boiling coolant, hard hot starts, possible hose or gasket damage. Stuck open: slow warm-up, poor heater, rich running, higher fuel use, and often a P0128 code. Leaks cause coolant loss and hot spots .

Pro tips from a master tech

Replace the seal, use fresh manufacturer-approved coolant mix, and bleed air carefully. Inspect hoses and cap during service for a complete, lasting repair ✅.

Compatible models

• Genesis
• Santa Fe
• Grand Santa Fe
• Palisade
• Equus
• Centennial
• Aslan
• Grandeur
• Grandeur HG
• Azera
• Maxcruz