Mishimoto · New
Mishimoto 2003+ Toyota 4Runner 4.0L Low-Temperature Racing Thermostat
MPN MMTS-4RUN40-03 · Store SKU misMMTS-4RUN40-03
Supplier stock checked 11/7/2026, 12:35:17 PM UTC. Adding a part does not reserve it.
Request a return within 30 calendar days after delivery. New parts must be unopened and unused.
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Product details
A defective thermostat can result in engine overheating and potential internal damage. Improve the reliability of your 2003-2024 Toyota 4Runner 4.0L cooling system with a Mishimoto Low-Temperature Racing Thermostat and housing! This thermostat is designed as a direct-fit replacement for your aged stock unit. The Mishimoto thermostat has a lower activation temperature (71?C/160?F) compared to the factory thermostat (82?C/180?F). The lower activation temperature allows coolant to flow through the engine earlier, which reduces and maintains lower engine temperatures. This thermostat is ideal for use in warmer climates, on vehicles making more power than stock, or under extreme towing/driving conditions. The stock-style housing will provide a proper seal and installs easily. Like all our Toyota Performance parts, this thermostat and housing includes the Mishimoto Lifetime Warranty. Engine coolant thermostat designed to regulate coolant flow and maintain optimal operating temperature. Ensures efficient warm-up, prevents overheating, and supports reliable performance with a precise fit. Racing Thermostat, Low-Temp, fits Toyota 4Runner 4.0L 2003-2024
Manufacturer fitment & guides
Check MMTS-4RUN40-03 against the manufacturer’s application information below.
Part-specific notes
- California Proposition 65: Y
