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If your Mitsubishi Outlander is showing temperature swings or slow warm-ups, the thermostat is often the cause. Picking the right thermostat matters because it directly affects engine warm-up time, fuel efficiency, heater performance, and long-term cooling system health. This guide highlights seven shortlisted thermostats chosen for reliable fitment and predictable temperature control.Below you will find a concise explanation of the evaluation criteria and the top options that meet those requirements, followed by details to help you pick the best thermostat for your Outlander.
Looking for other parts? See all Mitsubishi Outlander parts & accessories.
Top Picks at a Glance
| Best Overall The best all-around choice for most situations | A-Premium Engine Coolant Thermostat with O-ring (fits Mitsubishi Outlander and select Subaru/Toyota models) |  |
| Best Quality Built to a higher standard if you want something more solid | AISIN Engine Coolant Thermostat with Gasket (THM-007) |  |
| Best Value The sweet spot between price and what you get | MAXWIN Coolant Thermostat for Mitsubishi Outlander and compatible models |  |
| Best budget The cheapest option that still gets the job done reliably | Gates 33008 Engine Coolant Thermostat |  |
| Highest Rated A top-rated pick with lots of positive feedback | AISIN THM-006 Engine Coolant Thermostat with Gasket |  |
| Most popular A crowd favorite that many people choose with confidence | Gates 34198 Engine Coolant Thermostat |  |
| Best Seller A high-volume bestseller chosen again and again | AISIN THM-011 Engine Coolant Thermostat with Gasket |  |
1. A-Premium Engine Coolant Thermostat with O-ring (fits Mitsubishi Outlander and select Subaru/Toyota models)
| Start to Open Temperature | 87°C |
|---|---|
| Gasket or Seal Included | Yes |
| Material | Metal and Rubber |
| Package Quantity | 1 |
This A-Premium engine coolant thermostat is a direct replacement unit supplied with an O-ring gasket and built from metal and rubber components. It fits the Mitsubishi Outlander (and several Subaru and Toyota models listed by the manufacturer) and starts to open at 87°C, which places coolant flow into the radiator at the expected operating temperature. Install is typical for thermostat swaps and the included seal reduces the chance of immediate leaks during refit. The construction and factory-style profile aim to restore proper temperature control, helping the engine reach and maintain efficient operating temperature and prevent overheating. Notable limits are that fitment must match the reference numbers provided and this is a single thermostat without additional seals or housings beyond the included O-ring. Buyers should verify the exact part references before ordering and be prepared for a normal DIY or shop install rather than expecting any performance change beyond restoring proper thermostat function.
Best for: Balanced all-round buyers who want a reliable, factory-style replacement thermostat to restore proper engine temperature control on a Mitsubishi Outlander without seeking performance changes.
Less Ideal for: Drivers looking for performance thermostats, upgraded materials, or a complete housing kit should consider specialty alternatives rather than this direct replacement unit.
- Includes O-ring gasket to simplify installation and help prevent immediate leaks
- Factory-style metal and rubber construction intended to match original thermostat function
- Start-to-open temperature of 87°C aligns with typical engine operating ranges
- Fits Mitsubishi Outlander and other specified Subaru and Toyota applications when matched to reference numbers
- Compatibility is limited to the exact vehicle applications and reference numbers listed
- Sold as a single thermostat without additional housing components
Verdict: A practical, factory-style replacement thermostat with included gasket that restores proper temperature regulation for compatible Mitsubishi Outlander applications.
2. AISIN Engine Coolant Thermostat with Gasket (THM-007)
| Manufacturer | AISIN |
|---|---|
| Model | THM-007 |
| Manufacturer Part Number | THM-007 |
| OEM Part Number | 1305A048 |
The AISIN THM-007 is a factory-quality replacement thermostat intended to restore correct engine warm-up and cooling control on compatible Mitsubishi vehicles. It installs in place of the original thermostat and is supplied with a gasket to simplify the swap. AISIN states the unit matches OE operating temperature and form, which helps the engine reach and hold its designed coolant temperature for predictable thermostat opening and consistent cabin heating. For performance-minded owners this means stable thermal behavior under normal driving and reliable return to factory-specified temperatures after replacement. The machined exterior and OEM-specified temperature point reduce the chance of premature sticking or incorrect opening. Limitations to consider are fitment: ensure this exact part number matches your Outlander engine variant before buying, and the fixed operating temperature may not suit modified engines tuned to different thermostat setpoints.
Best for: Performance-oriented owners who prioritize factory-quality thermal control and stable operating temperature for stock or lightly modified Mitsubishi Outlander engines.
Less Ideal for: Drivers with heavily modified cooling or tuning requirements who need a nonstandard thermostat setpoint or active temperature control solutions.
- Factory-matched design for correct form, fit, and function
- Specified operating temperature intended to match OEM behavior
- Supplied gasket simplifies installation and avoids sourcing seals
- Machined exterior construction for durable, consistent operation
- Single fixed temperature may not suit performance builds that need a different setpoint
- Compatibility depends on engine variant so fitment must be verified
Verdict: A factory-quality, OE-matched thermostat option that restores correct coolant temperature control for compatible Mitsubishi Outlander engines.
3. MAXWIN Coolant Thermostat for Mitsubishi Outlander and compatible models
| Opening Temperature | 87°C / 189°F |
|---|---|
| Manufacturer | Maxwin Auto Parts |
| Manufacturer Part Number | NTH-0012 |
| Compatible Applications | Select Mitsubishi Outlander, Lancer and Subaru models (see vehicle fitment) |
This MAXWIN thermostat replaces the factory unit to regulate engine coolant flow and maintain correct operating temperature. It is typically used as a direct replacement when the cooling system shows overheating, poor warm-up, or during routine thermostat failure repairs. The unit lists an 87°C (189°F) opening temperature and is marketed to meet or exceed factory-quality standards, which helps restore normal warm-up behavior and prevent overheating on compatible engines. Installation is straightforward for anyone comfortable with basic cooling-system work and usually requires draining some coolant and refilling afterward. Practical benefits include a budget-friendly price, claimed OEM-level fit for the listed applications, and a local after-sales contact. Limitations include mixed fitment reports in user feedback, so confirming exact fitment by part number before ordering is important, and the product listing provides minimal technical detail beyond opening temperature.
Best for: Practical optimizers looking for an affordable, factory-quality replacement to restore normal cooling performance without paying dealer prices.
Less Ideal for: Buyers who prefer guaranteed dealer-fit parts or need exact factory part sourcing for highly tuned or modified engines should consider alternatives.
- Budget-friendly replacement compared with dealer parts
- Specified opening temperature of 87°C (189°F) for predictable thermostat operation
- Marketed to meet or exceed factory-quality standards
- Easy installation for routine cooling-system repairs
- Some buyers reported poor fitment on certain model years, so verification is needed before purchase
Verdict: A cost-effective, factory-quality thermostat replacement aimed at restoring correct engine temperature control for compatible Outlander and similar 4-cylinder models.
4. Gates 33008 Engine Coolant Thermostat
| Manufacturer Part Number | 33008 |
|---|---|
| OEM Part Number | 105000106400, 1447384M1, 4025103, 4513524, RE33705 |
| Position | Center |
| Exterior | Machined |
The Gates 33008 is a straightforward replacement engine coolant thermostat intended to regulate engine temperature by opening at its calibrated set point. It installs in the OEM thermostat housing and operates the same way as a factory-quality unit, helping the Mitsubishi Outlander reach and maintain operating temperature for efficient heating and cooling. The listing notes factory calibration for accurate opening and closing despite pressure changes, which translates to more predictable temperature control on the road. Customers report correct fit and reliable operation, though some users observed the valve opening a bit above the nominal temperature rather than like an instantaneous switch. The unit is discontinued by the manufacturer but still available from stock; expect a basic machined construction without extra features like integrated sensors. For budget-focused repairs this thermostat provides a cheap, factory-style replacement, but if you want premium longevity testing or ultra-precise dial-in temperatures you may prefer a higher-end aftermarket option.
Best for: Budget-conscious owners looking for a low-cost, factory-style replacement thermostat for routine maintenance on a Mitsubishi Outlander.
Less Ideal for: Drivers seeking ultra-precise temperature control, performance cooling upgrades, or extended-longevity specialty thermostats should consider premium aftermarket options instead.
- Factory-calibrated valve for predictable opening and closing under pressure changes
- Fits and installs as a direct replacement in compatible thermostat housings
- Simple machined construction with few failure points
- Widely reported correct fit and reliable function in user feedback
- Manufacturer shows the part as discontinued which may affect long-term availability
- May open a few degrees above the nominal rating rather than instantaneously at the listed temperature
Verdict: A cost-effective, factory-calibrated replacement for routine thermostat service on a Mitsubishi Outlander, but not the choice for precision or premium longevity.
5. AISIN THM-006 Engine Coolant Thermostat with Gasket
| Manufacturer Part Number | THM-006 |
|---|---|
| OEM Part Number | MD328070 |
| Position | Front, Rear |
| Brand | AISIN |
| Item model number | THM-006 |
This AISIN THM-006 thermostat is a direct-fit, factory-quality replacement designed to restore correct coolant control on compatible Mitsubishi models. It installs in place of the original thermostat and includes an O-ring gasket, so it is ready for a standard cooling-system service. AISIN builds the unit to match OEM operating temperature and form, which helps the engine reach and hold proper operating temperature and reduces overheating or long warm-up times. The machined exterior and OE matching claims suggest consistent operation and long life under normal driving. Limitations are that fitment depends on exact engine and year combinations so verify compatibility before purchasing, and it does not include extended hardware beyond the gasket so additional seals or hoses may be needed during a broader cooling-system refresh.
Best for: Reliability-focused buyers who prioritize long-term, factory-quality replacements and want a thermostat that restores correct engine temperature behavior without aftermarket performance changes.
Less Ideal for: Drivers looking for performance-modified thermostats, universal fit parts, or those needing a full cooling-system overhaul kit should consider other options.
- Factory-matched operating temperature for dependable cooling control
- Includes O-ring gasket for one-step replacement
- Machined exterior suggesting solid build quality
- Designed to provide correct OEM form, fit, and function
- Compatibility varies by engine and year so fitment must be verified before installation
- Contains only the thermostat and gasket so additional seals or parts may be required during installation
Verdict: A factory-quality, OEM-matched thermostat that reliably restores correct temperature control for compatible Mitsubishi Outlander applications.
6. Gates 34198 Engine Coolant Thermostat
| Manufacturer Part Number | 34198 |
|---|---|
| Position | Center |
| Exterior | Machined |
| OEM Part Number | 8890181680, 89018168, 89018168 |
This Gates 34198 thermostat is a factory-quality replacement intended to restore correct coolant flow and engine temperature control. It installs in the thermostat housing and opens at its calibrated temperature to allow coolant circulation, helping the engine warm up quickly and maintain stable operating temperature on highway and city driving. Notable features include quality-controlled calibration for consistent opening and closing, jiggle pins for air venting to reduce trapped air, and a machined exterior with included seals for a leak-resistant fit. In practice it behaves like a direct-fit factory replacement so installation is straightforward for routine DIY service or a quick shop job. Limitations are that fitment is vehicle-specific so you must confirm it matches the Outlander year and engine, and this unit is a basic mechanical thermostat without electronic temperature control or adjustable set points. If you need an advanced or programmable thermostat, this is not it, but for dependable, OEM-equivalent temperature regulation it is a practical choice.
Best for: Convenience-focused owners who want a straightforward, factory-style thermostat replacement that installs quickly and restores normal cooling system operation with minimal fuss.
Less Ideal for: Drivers seeking electronic, adjustable, or performance thermostats for tuning or specialized cooling control should look for a different product.
- Factory-quality calibration for consistent open/close behavior
- Jiggle pins and included seals reduce trapped air and leakage risk
- Machined exterior and OEM-equivalent fit simplify installation and replacement
- Mechanical fixed-temperature design so no electronic or adjustable control
- Fitment must be verified for specific Outlander year and engine before purchase
Verdict: A reliable, factory-style mechanical thermostat for owners who prioritize easy, direct-fit replacement over electronic or performance features.
7. AISIN THM-011 Engine Coolant Thermostat with Gasket
| Brand | AISIN |
|---|---|
| Included Components | Thermostat and O-ring gasket |
| Voltage | 12 Volts |
| Manufacturer Part Number | THM-011 |
| OEM Part Number | MD174233 |
This AISIN THM-011 thermostat replaces the vehicle's temperature-regulating valve and is supplied with a gasket for an out-of-the-box replacement. Installed in the cooling circuit, it opens at the OE-specified temperature to allow coolant flow and help maintain stable engine operating temperature. AISIN markets this as an OE-matched unit, which buyers will notice as consistent fit and the correct opening temperature for compatible engines. Typical installation is straightforward for DIYers comfortable with basic cooling-system work and involves draining some coolant, swapping the old thermostat and sealing with the included gasket. The practical benefits are predictable cooling performance, reduced risk of overheating when the old thermostat sticks, and long service life from quality manufacturing. Limitations are that fitment depends on the Outlander model year and engine variant so buyers must confirm exact compatibility, and installation still requires handling coolant and proper torque on the housing to avoid leaks.
Best for: Risk-averse mainstream buyers who prioritize factory-quality replacements and predictable, maintenance-minded ownership for their Mitsubishi Outlander.
Less Ideal for: Buyers seeking performance-modified thermostats or those who need a universal part that fits multiple vehicle models without checking fitment should look elsewhere.
- OE-matched design for accurate opening temperature and reliable fit
- Includes gasket for a complete thermostat housing seal during replacement
- Manufactured by a reputable supplier with consistent build quality
- Widely reported to fit and function correctly in compatible vehicles
- Requires confirming exact model-year and engine fitment before purchase
- Installation requires coolant handling and basic mechanical skills
Verdict: Choose this thermostat to get a factory-matched replacement that restores correct temperature control and reliable cooling system performance.
Choosing the Right Mitsubishi Outlander Thermostat: Key Factors to Consider
Correct Fitment and Compatibility
Confirming correct fitment is crucial because the thermostat must match the Outlander's coolant passages and mounting pattern. A physically incorrect unit can cause improper seating, leaks, or coolant flow restriction. When a thermostat fits as intended, installation is straightforward and the risk of coolant bypass or erratic temperature readings is reduced.
Fitment also affects the actuator orientation and how the thermostat interfaces with the housing and sensors. Using a part with clear vehicle-specific fitment information reduces the chance of returns and ensures the cooling system functions as designed.
Opening Temperature and Tolerance
Thermostats are specified to open at a particular temperature; choosing one that matches the Outlander's specified opening point helps maintain correct engine operating temperature. If the thermostat opens too early the engine may run cold, reducing efficiency and cabin heat. If it opens too late, the engine can overheat, stressing components and reducing reliability.
Also consider the tolerance or variance around the stated opening temperature. Units with tighter tolerances provide more consistent temperature control under varying loads and ambient conditions.
Sealing and Thermostat Housing Interface
A reliable seal between the thermostat and housing prevents coolant leaks and air ingress. Poor sealing can cause a thermostat housing seal leak that leads to pressure loss, localized overheating, or coolant contamination. Inspect designs that include robust gaskets, O-rings, or integrated seals to reduce leak risks.
Installation technique matters too; a well-designed seal reduces the need for excessive gasket sealant and lowers the chance of rework during service.
Material Quality and Corrosion Resistance
Thermostats operate in a hot, corrosive environment, so material choices affect longevity. Components made from corrosion-resistant metals or high-grade polymers last longer and maintain consistent movement over time. Inferior materials can seize or degrade, producing signs of bad thermostat such as sticking or inconsistent opening behavior.
Durable construction also helps withstand fluctuations in coolant chemistry and repeated heat cycles, extending service intervals and reducing the chance of mid-life failure.
Flow Characteristics and Warm-Up Performance
How the thermostat affects coolant flow determines warm-up speed and heater effectiveness. A thermostat that allows appropriate coolant bypass during warm-up helps the engine reach operating temperature quickly while still providing cabin heat. Conversely, excessive restriction can slow warm-up and cause uneven engine temperatures under load.
Consider designs that balance sufficient bypass flow with decisive opening at the rated temperature to optimize both engine efficiency and passenger comfort.
Serviceability and Installation Features
Easy serviceability reduces labor time and the chance of installation errors. Thermostats that are simple to access, install, and torque correctly reduce the risk of later leaks or misalignment. Features such as clear orientation marks, integrated seals, or compatible fastener patterns help technicians and DIYers perform a clean replacement.
Also consider whether the design facilitates common inspection steps, such as testing the thermostat without full disassembly, which ties into straightforward maintenance and diagnostics.
How We Chose the Best Mitsubishi Outlander Thermostat
Our selection process focused on factors that matter specifically for Mitsubishi Outlander owners. We prioritized correct fitment to the Outlander cooling circuit, accurate opening temperature that matches OEM specs, durable materials and construction for corrosion resistance, and reliable sealing at the thermostat housing to prevent leaks. We also considered flow characteristics that affect warm-up speed and heater performance, and unit compatibility with common service procedures for easier replacement.We excluded parts lacking clear fitment data for the Mitsubishi Outlander, items with inconsistent temperature ratings, and units without documented sealing solutions. The final list favors thermostats that balance accurate temperature response, housing sealing reliability, and serviceability for technicians and DIYers alike.
Our full evaluation process is outlined in our review methodology.
FAQ
What are common signs of a failing Mitsubishi Outlander thermostat?
Common signs include slow or inconsistent engine warm-up, the engine running cold because the thermostat is stuck open, or overheating when it is stuck closed. You may also notice coolant leaks at the housing or temperature gauge fluctuations under varying driving conditions. These symptoms often warrant inspection before replacing the part.
How do you test a thermostat to see if it is working?
Testing can be done by monitoring warm-up behavior and coolant flow; a thermostat that does not allow the engine to reach normal temperature may be stuck open. Another method is a controlled bench test where the thermostat is heated to observe the opening temperature, but this typically requires removal. Many technicians combine temperature observations with pressure checks to diagnose issues reliably.
Can a thermostat housing seal leak cause overheating?
Yes, a leaking housing seal can allow air into the cooling system and reduce coolant pressure, which may lead to localized hotspots and overheating. Even small leaks can change flow dynamics and interfere with accurate temperature regulation, so addressing sealing issues promptly helps prevent related cooling problems.
Will a stuck-open thermostat affect fuel economy or heater performance?
A thermostat that is stuck open often prevents the engine from reaching optimal operating temperature, which can reduce fuel efficiency and make cabin heating less effective. The engine control system may adjust fueling to compensate for the cooler engine, so you may notice reduced efficiency until the thermostat is corrected.
How often should the thermostat be replaced on a Mitsubishi Outlander?
There is no single interval that applies to all vehicles, as lifespan depends on driving patterns, coolant condition, and environmental factors. Thermostats are commonly inspected during routine coolant service and replaced when symptoms appear or when the cooling system is serviced. Replacing it when performing major coolant work can be a preventive step.
What should I check before assuming a thermostat is faulty?
Confirm coolant level, inspect for leaks at hoses and the housing, and verify the temperature sensor and gauge are functioning. Air trapped in the system or a weak water pump can mimic thermostat problems. Simple checks reduce unnecessary replacements and help pinpoint the real cause.
Conclusion
When choosing a thermostat for a Mitsubishi Outlander, prioritize correct fitment and the specified opening temperature to maintain consistent engine operation and reliable cabin heat. Balance sealing quality and material durability against serviceability to reduce the chance of leaks and simplify future maintenance.Be mindful of tradeoffs such as faster warm-up versus bypass flow characteristics. Inspect cooling system condition and verify symptoms before replacing the thermostat to ensure you address the underlying cause rather than just the symptom.
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- Check out all Mitsubishi Outlander parts & accessories
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