256002B003 Hyundai / KIA CONTROL ASSY-COOLANT TEMPERATU, Price: 39.25$, Weight: 0.278kg

Engine Coolant Temperature Control Assembly ??️

This unit keeps your engine at the ideal working temperature every trip. It speeds warm‑up after a cold start, stabilizes heat in traffic, protects the head gasket, and helps the ECU keep fuel trim and emissions in check. Built to OEM geometry for a precise seal and correct flow paths, it’s a direct-fit solution for many Hyundai and Kia platforms.

How it works ?

Inside is a wax‑pellet thermostat that reacts to coolant heat. Below the set point it routes flow through the bypass for fast warm‑up. As coolant reaches operating range, the valve opens the radiator circuit and meters the bypass. The integrated sensor feeds temperature to the ECU, coordinating fan speed, ignition timing, and mixture.

If it fails ⚠️

Stuck open: slow warm‑up, weak cabin heat, high fuel use, P0128. Stuck closed: rapid overheating, boiling coolant, risk of warped head or blown gasket. Cracked housing or bad seal: leaks, low coolant, air pockets, unstable idle. Faulty sensor: late/early fan, rich or lean running.

Tech tips ✅

Install with a new O‑ring, no sealant. Refill with the correct HOAT/OAT coolant mix, bleed air, and verify fan cut‑in. Torque bolts evenly to avoid warping the housing.

Compatibility

• Hb20
• Creta
• i30
• i30 Cw
• ix20
• i20
• i10
• Accent
• Verna
• Venue
• Avante
• Avante Hybrid
• Elantra
• Veloster
• Solaris