TAMKKEN Coolant Thermostat for Toyota Lexus - 90916-A3003 / 90916-03129 Direct-Fit OEM Replacement

The TAMKKEN 90916-A3003 coolant thermostat is a direct-fit replacement designed to restore proper coolant flow and temperature control in compatible Toyota, Lexus and Scion models.

This precision thermostat matches OEM specifications to help maintain engine operating temperature, reduce overheating risk, and clear related fault codes when installed correctly. Manufactured from quality materials and tested before shipment, the unit is intended as a plug-and-play replacement that does not require special programming. The listing covers a wide range of model years for Toyota, Lexus and Scion vehicles—check fitment carefully against part numbers to ensure compatibility.

Which vehicles will this thermostat fit?

The TAMKKEN 90916-A3003 supports many Toyota, Lexus and Scion models across multiple years. Verify the part numbers 90916-A3003, 90916A3003, 90916-03129 or 9091603129 against your vehicle's requirements before purchasing.

• Toyota: Avalon, Camry, Celica, Corolla, Highlander, Matrix, MR2 Spyder, Prius, RAV4, Sienna, Solara, Tacoma, Venza, Yaris (various years listed).
• Lexus: ES300/ES330/ES350, GS300, IS300, LS400, RX300/RX330/RX350/RX400h/RX450h, SC300/SC400 (years included).
• Scion: tC, xB, xA, xD models in specified years.
• Always cross-check the vehicle year and engine variant to confirm fitment.

How does installing this thermostat affect engine performance?

Replacing a failing thermostat helps the cooling system regulate temperature more reliably, preventing overheating or prolonged cold running. A correctly operating thermostat helps the engine reach and maintain optimal temperature faster, which supports consistent performance and emissions control.

• Restores proper coolant circulation for stable engine temps.
• Can reduce temperature-related fault codes and warning lights.
• Designed as a direct replacement—no calibration or ECU programming needed.

Is this thermostat durable and easy to install?

The unit is manufactured from quality components and undergoes bench testing before shipping to ensure stable performance and longevity. Installation is straightforward for mechanically inclined DIYers and many professional technicians, typically requiring only basic tools and the steps outlined below.

• Box packaging; built to meet OEM standards and withstand road conditions.
• Installation steps: diagnose and remove faulty sensor, disconnect wiring, plug in the new unit, clear trouble codes.
• Designed as a direct-fit part; no special tools or programming usually required.

What warranty and support options are available?

TAMKKEN provides a one-year warranty on this part; contact the seller first for a faster resolution if you experience a problem within that period. The manufacturer encourages customers to reference part images and fitment details before ordering to avoid purchasing the wrong item.

• One-year warranty—contact seller for quicker solutions.
• Pre-shipment testing performed to reduce DOA incidents.
• Customer reminder: verify part number and images before buying.

Who is this for? Mechanics, experienced DIYers and fleet managers who maintain Toyota, Lexus or Scion vehicles listed in the compatibility section will find this thermostat suitable as a cost-effective direct replacement. If you need a reliable OEM-style thermostat to resolve temperature regulation issues or clear cooling-system fault codes, confirm fitment and consider this TAMKKEN part for a straightforward swap.