Heating and Cooling› Thermostats, Housings and Fillers
Mishimoto
Mishimoto 2003+ Toyota 4Runner 4.0L Low-Temperature Racing Thermostat
SKU: M00C MMTS-4RUN40-03
Moderate — 2–4 hours
Description
Part #: MMTS-4RUN40-03
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.
Features:
- Direct fit for 2003+ Toyota 4Runner 4.0L
- Stock-style housing includes pre-installed low-temperature thermostat for easy install
- The lower activation temperature allows coolant to flow through the engine earlier, which yields and maintains lower engine temperatures (71?C/160?F compared to the factory thermostat at 82?C/180?F)
- Ideal for use in hot climates, on modified vehicles, or in extreme towing/driving conditions
- 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.
MIA's Description
Fitment
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Specifications
| Brand | Mishimoto |
| Part Number | M00C MMTS-4RUN40-03 |
Buy with Confidence
Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.
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