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If your Acura TLX is showing erratic temperature readings or running too hot or too cold, swapping the thermostat can often restore normal engine operation. Choosing the right Acura TLX thermostat matters because the correct part maintains proper coolant flow, helps the engine reach optimal operating temperature, and prevents long-term wear.This guide shortlists the top thermostat options for the Acura TLX based on fitment and thermal performance. We evaluated installation compatibility, opening temperature, and build quality to find reliable choices. Read on to see which thermostats made our shortlist and why they are suitable for this vehicle.
Looking for other parts? See all Acura TLX parts & accessories.
Top Picks at a Glance
| Best Overall The best all-around choice for most situations | Genuine Acura 19301-P8E-A10 Thermostat Assembly |  |
| Best quality Built to a higher standard if you want something more solid | AISIN THH-003 Engine Coolant Thermostat with Housing and Gasket |  |
| Best Value The sweet spot between price and what you get | Gates 33914 Engine Coolant Thermostat |  |
| Best budget The cheapest option that still gets the job done reliably | MotoRad 636-170 Integrated Housing Thermostat (170°F) |  |
| Highest Rated A top-rated pick with lots of positive feedback | ROVIKE Engine Thermostat (replaces 19301-PAA-306) |  |
| Most Popular A crowd favorite that many people choose with confidence | TRQ Thermostat with Aluminum Housing Assembly for Acura/Honda 2.0–2.4L |  |
| Best Seller A high-volume bestseller chosen again and again | A-Premium Engine Coolant Thermostat with Gasket |  |
1. Genuine Acura 19301-P8E-A10 Thermostat Assembly
| Brand Name | Acura |
|---|---|
| Model Name | Nippon Thermostat |
| Model Number | 19301-P8E-A10 |
| Power Source | Vehicle Electrical System |
| Material Type | Metal |
This genuine Acura thermostat assembly replaces the vehicle's factory unit to restore proper cooling system temperature control. It is used during thermostat failures or coolant system service and installs in the original thermostat housing using the factory mounting points and seal. Notable features include factory manufacturing by Nippon Thermostat, a metal construction, and inclusion of a new seal for a direct-fit replacement that matches factory operation. In practice the unit brings coolant warm-up and operating temperature back to expected ranges, improving heater performance and preventing prolonged cold running that can accelerate engine wear. The clear benefit is factory-fit reliability and long service life compared with lower-cost aftermarket alternatives. The main limitation is cost relative to aftermarket parts and the installation still typically requires a full coolant drain and refill and some work to access the housing on certain Acura TLX engines.
Best for: Balanced owners who want a reliable, factory-quality replacement to maintain engine temperature control and avoid compatibility guesswork.
Less Ideal for: Buyers seeking the lowest upfront cost or a quick temporary fix who are comfortable with aftermarket alternatives and frequent replacements.
- Factory genuine Acura part for direct-fit replacement and correct thermostat operation
- Metal construction and manufactured by a reputable supplier for long-term durability
- Includes a new seal to simplify installation and ensure a proper coolant seal
- Proven in-vehicle performance that restores correct warm-up and operating temperatures
- Higher price than many aftermarket thermostat options
- Installation requires coolant drain/refill and may be awkward in tight engine bays
Verdict: A factory genuine thermostat assembly that provides reliable, direct-fit temperature control for Acura vehicles seeking a long-lasting replacement.
2. AISIN THH-003 Engine Coolant Thermostat with Housing and Gasket
| Manufacturer Part Number | THH-003 |
|---|---|
| OEM Part Number | 19301-RAF-004 |
| Exterior | Machined |
| Position | Center |
This Aisin thermostat assembly replaces the engine coolant thermostat and comes with the housing and gasket to simplify installation. Designed to match factory-specified operating temperature, it regulates coolant flow to help the engine reach and hold the correct operating temperature quickly and consistently. The machined exterior and OEM-matched design mean the part fits like a factory-quality unit and reduces the chance of leaks when the included gasket is installed. In practice the unit is used during routine cooling system repairs or when a failing thermostat causes overheating or poor warm-up. A common limitation is that hardware bolts are not included, so you may need replacement bolts if originals are corroded. Also fitment depends on engine and model year details, so verify compatibility for a specific Acura TLX variant before ordering. For performance-focused owners this thermostat delivers predictable temperature control and durable construction but requires basic mechanical skills to install and may need extra fasteners.
Best for: Performance-oriented buyers who prioritize accurate, factory-quality temperature control and want a direct replacement that behaves like the original part.
Less Ideal for: Buyers seeking a complete DIY kit with every fastener included or those unwilling to check exact TLX engine fitment should consider other options.
- Factory-matched operating temperature for consistent engine warm-up and cooling
- Includes thermostat housing and gasket for a more complete replacement
- Machined exterior and OEM-style construction for durable, reliable fit and function
- Mounting hardware (bolts) is not included, which can complicate installation on older cars
- Compatibility depends on engine variant and model year so fit must be confirmed before purchase
Verdict: Aisin's THH-003 is a factory-quality thermostat assembly that delivers reliable, OEM-like temperature control for buyers focused on performance, but verify TLX engine fitment and plan for missing hardware.
3. Gates 33914 Engine Coolant Thermostat
| Manufacturer Part Number | 33914 |
|---|---|
| Material | Metal |
| Voltage | 12 Volts |
| Mounting Type | In-Line |
The Gates 33914 is a simple metal replacement thermostat that regulates engine coolant flow by opening at its calibrated temperature. It installs in-line with the cooling system and is intended as a direct replacement where the part number fits; typical use is to restore normal warm-up time and prevent overheating caused by a stuck-open unit. Notable points are factory-controlled calibration for consistent opening and closing under pressure and sturdy machined metal construction for durability. Many buyers report correct fit and steady temperature control after installation, though the part sometimes ships without a gasket so you should plan to have the seal or correct gasket on hand. A few listings indicate manufacturing or packaging inconsistencies, which means inspect the unit before installation. For a practical owner looking to replace a failing thermostat and maintain proper engine temperature, this provides straightforward function and good value, but you may need to source the correct gasket and verify the opening temperature if your TLX requires a specific spec.
Best for: Practical optimizers who prioritize a cost-effective, reliable factory-quality replacement to restore normal warm-up and cooling behavior on their Acura TLX.
Less Ideal for: Buyers who need a thermostat with a nonstandard opening temperature or who want a guaranteed complete gasket kit included should consider a different option or purchase the gasket separately.
- Factory-controlled calibration for predictable opening and closing under pressure
- Machined metal construction offers durability compared with cheaper stamped parts
- Fits directly in-line as a straightforward replacement when the part number matches
- Widely available replacement with a history of working in Honda/Acura 3.5L applications based on user reports
- Gasket is not consistently included so a separate seal may be required
- Some listings report the part came from a different OEM brand or had packaging inconsistencies
Verdict: A durable, factory-calibrated replacement thermostat that delivers reliable temperature control for TLX owners — just buy the gasket if it is not included.
4. MotoRad 636-170 Integrated Housing Thermostat (170°F)
| Opening temperature | 170 Degrees |
|---|---|
| Replaces part numbers | 19301RAF003, 19301RAF004 |
| Position | Center |
This MotoRad integrated housing thermostat replaces the factory thermostat and housing in compatible Acura and Honda 2.4L K-series vehicles and is intended for straightforward in-vehicle replacement. It combines the thermostat and housing into a single unit, so installation eliminates the need to transfer the old housing and helps avoid separate gasket sealing on many installs. The 170°F opening temperature matches common factory spec for the covered models, restoring proper engine warm-up and cooling regulation. Buyers report it fits and functions like the factory part and can clear P0128 codes and overheating symptoms when the original unit fails. Installation can be tight on some engines; the included O-ring may be awkward to seat and extra patience or partial disassembly of nearby components can help. This is a cost-effective alternative to a dealer part, but those seeking an exact factory-branded component or an upgraded performance thermostat should look elsewhere.
Best for: Cost-conscious Acura TLX owners who prioritize an affordable, direct-fit replacement that gets the cooling system back to factory-like operation without paying dealer prices.
Less Ideal for: Owners looking for a factory-branded OEM part or a performance/upgraded thermostat that changes operating temperature or flow characteristics should consider other options.
- Integrated housing plus thermostat simplifies replacement and reduces parts to install.
- 170°F opening temperature matches common factory cooling calibration for the listed engines.
- Multiple reviewer reports of good fit and restored cooling function on compatible Acura models.
- Lower-cost alternative to dealer or factory-brand replacements.
- O-ring can be difficult to keep in place during installation on some engines.
- Integrated design means replacing the whole housing if one small component fails rather than swapping only the thermostat.
Verdict: A wallet-friendly, direct-fit integrated thermostat and housing that restores proper cooling on compatible Acura TLX 2.4L applications but requires replacing the entire housing if anything fails.
5. ROVIKE Engine Thermostat (replaces 19301-PAA-306)
| Included Components | Engine Thermostat |
|---|---|
| Manufacturer Part Number | 19301-PAA-306 |
| OEM Part Number | 19301-PAA-306, 19301-PLC-315, 19301PAA306, 9301PLC315 |
| Manufacturer | ROVIKE |
This ROVIKE thermostat is a simple, direct-replacement cooling system component intended to open and close at its designed temperature to regulate engine coolant flow. Installers use it when a failing thermostat causes overcooling, overheating, or a check-engine code related to engine temperature. The product is sold as a single replacement part that the listing says is inspected before shipment and compatible with many Honda and Acura year ranges that originally used part 19301-PAA-306. In practice the unit offers the expected benefit of restoring proper engine warm-up and stable operating temperature when it matches the vehicle’s original part number. Multiple buyers report an exact fit and reliable operation, though a minority report defects or size mismatches on certain models, so confirming the part number is important before ordering. Installation can be fiddly on some cars because of tight access to the housing. This thermostat is best for owners who want a straightforward, budget-friendly replacement and are comfortable verifying fitment and performing or arranging installation.
Best for: Reliability-focused buyers who prioritize restoring correct engine temperature with a straightforward, cost-conscious replacement and who will verify part numbers before purchasing.
Less Ideal for: Drivers who prefer factory-authorized parts with guaranteed calibration or those who want a plug-and-play boxed kit with detailed fitment confirmation for the Acura TLX specifically.
- Direct replacement that lists factory part number equivalents for easy verification.
- Commonly compatible with many older Honda and Acura models that used part 19301-PAA-306.
- Simple single-part swap restores coolant flow and engine warm-up when fitment is correct.
- Low-cost option compared with dealer-sourced thermostats.
- Some buyers reported defective units or incorrect size for certain models, so quality can vary between batches.
- No temperature rating or calibration detail is provided in the listing, so buyers must rely on part-number matching.
Verdict: A budget-friendly direct-replacement thermostat useful for restoring proper engine temperature when the listed part numbers match, but confirm fitment and accept some variability in quality.
6. TRQ Thermostat with Aluminum Housing Assembly for Acura/Honda 2.0–2.4L
| Opening Temperature | 172 Deg. F / 78 Deg. C |
|---|---|
| Fitment (engines) | Acura/Honda 2.0L–2.4L applications listed |
| Manufacturer | TRQ |
| Exterior | Machined |
This TRQ thermostat with housing assembly is a preassembled, direct-fit replacement intended for a range of Acura and Honda 2.0–2.4L engines such as the ILX, RDX, TSX, Civic, and CR-V. It installs in place of the factory unit to restore proper coolant regulation and clear engine temperature codes. Notable features include a machined exterior housing, a thermostat calibrated to open at 172 F (78 C), and included seals and bleed hardware to simplify installation. For a convenience-focused buyer the assembly saves time because you receive the thermostat already mounted in the housing, reducing parts swapping and the chance of leaks from reused O-rings. Some customers report occasional fitment interference with surrounding bolts on certain models, so test-fitment and replacing old fasteners may be necessary. While many buyers praise the durability and leak-free performance, fitment variance across model years means confirming compatibility before installation.
Best for: Convenience-driven owners who want a ready-to-install, factory-style replacement that minimizes labor and parts-sourcing when repairing cooling systems on compatible Acura/Honda 2.0–2.4L models.
Less Ideal for: Owners seeking a guaranteed metal upgrade or exact OEM-identical materials across all years should verify the housing material and fitment closely or consider a dealer-sourced replacement.
- Preassembled direct-fit design reduces installation time and eliminates thermostat transfer
- Thermostat calibrated to open at 172 F (78 C) for reliable coolant regulation
- Machined housing construction marketed as higher quality than OEM plastic units
- Includes seals and bleeder hardware to help prevent leaks after install
- Some vehicles report minor fitment interference with nearby bolts requiring adjustments
- Materials may vary between plastic and aluminum listings, causing uncertainty about housing construction
Verdict: A convenient, preassembled direct-fit thermostat housing that gets compatible Acura and Honda 2.0–2.4L engines back to correct operating temperature with minimal hassle.
7. A-Premium Engine Coolant Thermostat with Gasket
| Start to Open Temperature (℃) | 77 |
|---|---|
| Gasket or Seal Included | Yes |
| Material | Metal and Rubber |
| Package Quantity | 1 |
This A-Premium thermostat is a direct-replacement style coolant thermostat intended to regulate engine temperature by opening at about 77°C. It is typically used when replacing a failed or aging thermostat during routine cooling system service. The unit ships with a gasket and combines metal and rubber components similar to factory replacements, so installation follows the same steps as a stock thermostat and fits into the existing housing. Practical benefits include the near-factory opening temperature for predictable temperature control and a boxed single-piece supply that simplifies keeping a spare on hand. Limitations are typical of aftermarket value parts: build quality can vary between batches and a few customers reported early failures or minor fit adjustments, so careful inspection at installation is advised. For a risk-averse buyer focused on long-term durability, this is a reasonable budget replacement but not a guaranteed long-life upgrade over factory-quality parts.
Best for: A risk-averse mainstream buyer who prioritizes reliable, budget-friendly replacement parts and wants a thermostat that matches typical factory temperature behavior for routine maintenance on their Acura TLX.
Less Ideal for: Drivers seeking a premium long-life performance upgrade or motorsport-level cooling control should consider higher-end OEM-equivalent or performance thermostats instead.
- Opens at approximately 77°C, matching common factory operating temperature for consistent cooling behavior
- Includes gasket for a complete seal at installation
- Metal-and-rubber construction mimics factory-style components for straightforward fitment
- Aftermarket quality varies so some units may fail earlier than factory replacements
- Fitment sometimes requires minor trimming or adjustment on certain housings
Verdict: A budget-friendly, near-factory replacement thermostat that matches normal operating temperature but may not match OEM longevity for owners needing maximum durability.
Choosing the Right Acura TLX Thermostat: Key Factors to Consider
Correct Fitment and Part Number Match
Ensuring the thermostat matches the Acura TLX flange geometry and mounting points affects fit and sealing. A correct part number or explicit fitment listing reduces the risk of leaks and misalignment.
Incorrect fitment can cause coolant bypass or pressure issues, leading to overheating or poor cabin heating. Always check mounting bolt pattern, overall diameter, and how the thermostat seats in the housing to avoid installation problems.
Rated Opening Temperature
The thermostat's rated opening temperature determines when coolant flow begins and directly influences engine operating temperature. Choosing a thermostat with the OEM-specified opening temperature helps maintain intended thermal efficiency and emissions performance.
A thermostat that opens too early can cause the engine to run cold, while one that opens too late can lead to overheating. Buyers should confirm the specified opening temperature and seek parts that match manufacturer recommendations.
Valve Design and Actuation Reliability
Durable valve mechanisms and reliable actuation ensure consistent operation over time. Materials like stainless steel or high-quality brass for the valve and spring assemblies resist corrosion and mechanical wear.
A sticky or weak valve can result in thermostat sticking closed or open, causing overheating or engine running cold thermostat stuck open conditions. Look for parts with proven materials and sealing designs to minimize failure risk.
Seal and Gasket Quality
High-quality seals and gaskets reduce the chance of thermostat housing seal leak issues. Materials such as molded rubber or reinforced composite gaskets provide better conformity and longevity under thermal cycling.
Poor gasket materials can harden or compress unevenly, leading to coolant loss and air ingress. Inspect the replacement part's sealing surface design and whether a new gasket or O-ring is included with the thermostat.
Ease of Installation and Serviceability
A thermostat that is straightforward to install reduces labor time and the potential for installation errors. Clear instructions, compatibility with factory hardware, and inclusion of necessary seals make replacement more reliable.
Parts that require minimal additional disassembly or nonstandard tools are preferable for routine service. Consider how accessible the thermostat housing is on the Acura TLX and whether the part allows quick reassembly without special modifications.
Corrosion Resistance and Long-Term Durability
Thermostats operate in a harsh environment of heat, coolant, and chemical exposure, so corrosion-resistant materials extend service life. Coatings, stainless components, and quality springs resist degradation from coolant additives and temperature cycles.
Long-lasting components reduce the likelihood of repeated failures and the need for further engine cooling system work. Factor expected lifespan and warranty coverage into decisions when possible.
How We Chose the Best Acura TLX Thermostat
We focused on parts that meet OEM or equivalent fitment specifications and that are designed specifically for the Acura TLX. Key filters included correct flange and gasket dimensions, mounting pattern compatibility, and verified part number fitment to ensure straightforward installation on this vehicle.Thermal performance was measured by rated opening temperature and how consistently the valve actuates across expected operating ranges. We also prioritized corrosion-resistant materials, durable valve mechanisms, and robust seals to reduce the risk of a thermostat housing seal leak over time.Ease of installation and serviceability mattered as well, including whether the part allowed for straightforward replacement without extensive disassembly. We excluded generic universal thermostats and any parts lacking clear fitment data or documented specifications for the Acura TLX. Final selections balanced fitment accuracy, thermal response, and long-term durability for this model.
Our full evaluation process is outlined in our review methodology.
FAQ
What are common thermostat symptoms overheating in an Acura TLX?
Common signs include a rapidly rising temperature gauge, coolant boiling in the overflow, or the heater producing little to no warm air. You may also notice the radiator fan running continuously. These symptoms often indicate the thermostat is stuck closed or not opening fully.
How to test a thermostat on an Acura TLX safely?
A basic test is to monitor engine temperature from cold start and observe when the upper radiator hose warms, which indicates the thermostat opening. For a bench test, heat coolant in a pot with a dial thermometer and observe at what temperature the thermostat valve begins to open. Always follow safety precautions for hot coolant and never remove the radiator cap when the system is hot.
Can a thermostat cause the engine running cold thermostat stuck open condition?
Yes, a thermostat that is stuck open will allow continuous coolant flow, preventing the engine from reaching normal operating temperature. That can reduce fuel efficiency and cabin heating performance. The condition often presents as a persistently low temperature gauge reading.
What causes a thermostat housing seal leak?
Seal leaks commonly result from degraded gaskets, improper installation torque, or a warped housing surface. Thermal cycling and coolant chemistry can harden or erode gasket materials over time, leading to small coolant leaks around the thermostat housing.
How do I confirm thermostat part number fitment for an Acura TLX?
Check the vehicle's year and engine specifications against OEM part numbers or referenced fitment guides. Look for explicit compatibility listings that include the Acura TLX model year and engine code, and verify flange dimensions where available to ensure a correct match.
How will replacing the thermostat affect engine performance?
A properly functioning thermostat helps the engine reach and maintain the intended operating temperature, which supports efficient combustion and emissions control. Replacement often restores normal warm-up times and consistent cabin heat, while resolving issues like overheating or running too cold.
Conclusion
Choosing the right Acura TLX thermostat comes down to fitment accuracy, correct opening temperature, and durable construction. Prioritize parts that match the vehicle's part number and flange dimensions, and that use corrosion-resistant materials and reliable valve mechanisms.Be mindful of tradeoffs between longevity and ease of installation. Addressing seal quality and ensuring correct installation will reduce the chance of future coolant leaks and help maintain consistent engine temperature control.
Explore More:
- Check out all Acura TLX parts & accessories
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