Engine Coolant Thermostat Guide for the 2012-2018 BMW M6
Keep your M6's high-performance S63 engine from running too hot or too cold.
- The most common failure is stuck-open, which triggers a P0128 code and is not immediately critical.
- Check with a BMW dealer about the 15-year/150,000-mile extended warranty on the thermostat before paying for a repair.
- Due to high labor costs, consider replacing the water pump and turbo coolant lines at the same time as the thermostat.
- OEM-supplier brands like Mahle or Wahler offer a balance of quality and cost, while standard aftermarket like Gates is a reliable budget option.
Is Your M6 Thermostat Failing?
The thermostat in the 2012-2018 BMW M6 is designed to fail in the "stuck open" position. This is a safety measure to prevent catastrophic engine damage from overheating. While safer, it means your engine will struggle to reach its proper operating temperature. Here are the most common signs of failure:
- Check Engine Light: The most frequent symptom is a check engine light with the code P0128, which means the coolant temperature is below the regulating temperature. 🎬 Watch: How to diagnose and fix a P0128 fault code.
- Engine Not Warming Up: You may notice the temperature gauge on your dash never reaches the middle, even after driving for a while.
- Poor Heater Performance: If the engine isn't getting hot enough, the heater in the cabin may only blow lukewarm air.
- Decreased Fuel Economy: An engine that runs too cool is less efficient, leading to worse gas mileage.
- Engine Overheating: In the rare and much more dangerous event the thermostat fails while stuck closed, your engine will quickly overheat, causing the temperature gauge to spike into the red. If this happens, pull over immediately to prevent severe engine damage.
Known Issues & Warranty Extension
BMW of North America has extended the limited warranty for the engine coolant thermostat on some vehicles with N63-family engines to 15 years or 150,000 miles. This covers defects in materials or workmanship. Before paying for a repair, check with a BMW dealer to see if your M6 is covered under this warranty extension. Additionally, be aware of related cooling system issues like TSB B11 08 17, which addresses potential leaks from turbocharger coolant lines due to high temperatures.
Choosing the Right Aftermarket Thermostat
When replacing the thermostat on a high-performance car like the M6, part quality is crucial. While an OEM part is always a safe bet, quality aftermarket brands can offer a reliable alternative at a better price. The thermostat for the S63 engine is a complete assembly, including the plastic housing and integrated sensor.
Brand Tiers for Your M6
- Tier 1 (OEM & OEM-Equivalent): Brands like Mahle and Wahler are often the original equipment manufacturers for BMW. Choosing one of these is the closest you can get to dealer quality without the dealer price tag. They are built to the original specifications for temperature and electronic control.
- Tier 2 (Quality Aftermarket): Gates is a well-known aftermarket manufacturer that produces a replacement thermostat for the M6. These parts are designed to be a direct-fit, cost-effective replacement for the original and are a solid choice for a standard repair.
- Tier 3 (Performance Aftermarket): Brands like Mishimoto are known for performance cooling parts. They sometimes offer lower-temperature thermostats (e.g., 90°C instead of the stock 101°C). While this can lower overall engine temperatures, it's not always a good idea for a street-driven M6. Running the engine cooler than designed can decrease fuel efficiency and may trigger a P0128 check engine light if the engine's computer isn't tuned for it.
Pro Tip: The thermostat replacement is labor-intensive. To save on future labor costs, it is highly recommended to replace other cooling system components at the same time, such as the water pump and any accessible coolant hoses, 🎬 See this step-by-step N63 water pump and thermostat replacement guide. especially the turbo coolant lines.
Cost to Replace a BMW M6 Thermostat
| Part/Service | Estimated Cost |
|---|---|
| New OEM Part | $101 - $140 |
| New Aftermarket Part (Gates, Mishimoto) | $112 - $140 |
| Shop Labor | $474 - $696 |
| Total Estimated Repair | $586 - $836 |
Frequently Asked Questions
Can I drive my M6 with a bad thermostat?
If it is stuck open (causing a P0128 code and low temps), you can drive short distances, but you should get it repaired soon to avoid poor fuel economy and excess engine wear. If it is stuck closed (causing overheating), you should not drive the car at all. Pull over immediately and have it towed to prevent catastrophic engine damage.
🎬 Learn more about the symptoms of a thermostat stuck open.Is an OEM BMW thermostat better than aftermarket?
For a critical, electronically controlled part on a complex engine like the S63, OEM or an OEM-supplier brand like Mahle or Wahler is often recommended for the best reliability and fit. However, a quality aftermarket brand like Gates provides a dependable, budget-friendly alternative that meets standard specifications.
What temperature should my M6 engine run at?
The S63 engine is designed to run hot for efficiency, with normal operating temperatures often above 210-220°F (99-105°C). The temperature gauge on the dashboard should sit right in the middle once the car is fully warmed up.
Are there any recalls on the M6 thermostat?
There are no specific recalls for the thermostat on the 2012-2018 BMW M6. However, BMW has issued a limited warranty extension for this part on some vehicles to 15 years/150,000 miles, which may cover the cost of replacement. There have been recalls and service campaigns on related cooling system parts for BMWs, so it's always wise to check with a dealer.
Helpful Videos
Technical Specifications
OEM Part Numbers: 11537586885 11537502779 11530304425
Electronically map-controlled thermostat assembly with integrated housing and sensor. Standard opening temperature is 101°C (214°F).
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- BMW M6: