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Wahler
Wahler for Porsche
With the WAHLER brand, under the umbrella of Thermal Management Solutions, we offer you a diverse and particularly broad product portfolio of thermostats and oil temperature thermostats in the highest OE quality. With over 120 years of technology experience and more than six million products sold worldwide every year, WAHLER is one of the leading brands for thermostats and oil temperature thermostats
Choosing the Right Fit for Your Porsche
Where Wahler is listed for Porsche, use the supplied model coverage and OE references to confirm suitability. Check details that commonly affect fitment such as model year, side/position, and connector type where relevant.
- Typical reasons to replace include slow warm-up, overheating, or inconsistent running temperatures, and restoring correct cooling system behaviour after age-related wear.
- Common symptoms before replacement include overheating, temperature fluctuations, slow warm-up, and heater performance issues, which can also be linked to other cooling components.
- Consider replacing related cooling parts such as the water pump or expansion tank cap at the same time where mileage is high or issues are suspected.
- Use the correct bleeding procedure to avoid air locks and pressure-test the system if you suspect leaks or recurrent temperature problems.
- Simple checks like replacing a weak cap or confirming coolant level and condition can have a big impact on overall system reliability.
Browse by Category
If you already know the area you are working on, start with the category and then filter by Porsche model. Where real-world symptoms and typical reasons to replace are provided, use them to keep the wording grounded.
Engine Cooling — Cooling parts are typically replaced when there are leaks, overheating, repeated low coolant warnings, or ageing hoses and clamps, and owners look for reliable components because cooling failures can quickly lead to serious engine damage. Tips: Regularly check coolant level and look for staining or dampness around joints; avoid driving with known leaks as overheating can escalate very quickly.
Thermostat / Temperature Sensor — These parts are changed when temperature behaviour is unstable, the engine runs too hot or too cold, or when diagnostics show implausible readings or temperature-related fault codes from the sensor. Tips: Compare scan-tool data with gauge behaviour and warm-up rate, and observe hose temperatures to distinguish thermostat issues from sensor or wiring faults.
Engine Rebuild Parts — Internal engine components are renewed during rebuilds or when tests show low compression, high oil consumption, abnormal noises, or contamination in the oil, and owners often replace a wide range of wear items while the engine is apart to avoid repeat strip-downs. Tips: Before committing to a rebuild, carry out compression and leak-down tests, bore inspection, and oil/filter checks to confirm the true extent of internal wear.
Engine Tuning — Tuning work and related components are chosen to improve drivability, throttle response, fuel economy, or to support hardware changes, and should always be carried out on a mechanically healthy engine with stable cooling and lubrication. Tips: Check compression, fueling, sensor data, and for any boost or vacuum leaks before tuning, as calibration changes cannot compensate for underlying mechanical faults.
Thermostats — Thermostats are replaced when they stick open or closed, causing slow warm-up, overheating, or fluctuating temperatures, and many Porsche owners renew them proactively during cooling system overhauls to maintain stable engine temperatures. Tips: Plan to refresh coolant and bleed the system correctly when changing the thermostat, and be aware that thermostat faults can mimic water pump issues so careful diagnosis is important.
Explore Wahler at Design911
View the current Wahler range for Porsche at Design911, then filter by model and category to narrow down to the right parts.
- Porsche 997 MK1 GT3 2007-09
- Porsche 997 MKII GT3 2010-11
The Wahler Water Pump Thermostat Insert is a Porsche 997 GT3 cooling system component designed to regulate coolant flow through the engine and radiator system. Installed within the thermostat or water pump housing, this insert opens and closes at specific temperatures to ensure the engine maintains its ideal operating range for efficiency, performance, and reliability.
Fits:
- Porsche 997 MK1 GT3 2007-09
- Porsche 997 MKII GT3 2010-11
Diagram Ref No 8
What This Product Does:
- Regulates coolant circulation through the engine cooling system
- Maintains optimal engine operating temperature
- Controls engine warm-up and cooling efficiency
- Works with the water pump and radiator to stabilise temperatures
- Helps prevent overheating and overcooling
- Supports fuel efficiency, emissions control, and engine performance
Symptoms Of Wear Or Failure:
- Engine overheating Engine running too cool or slow to reach operating temperature
- Fluctuating temperature gauge readings
- Poor cabin heater performance
- Coolant leaks around the thermostat housing
- Reduced fuel efficiency caused by incorrect engine temperature
- Check engine light related to cooling system faults
Why Replacement Matters:
- Restores proper coolant flow and temperature regulation
- Prevents overheating and potential engine damage
- Improves engine efficiency and fuel economy
- Ensures reliable heating and climate control performance
- Protects cooling system components from excessive stress and wear
- Maintains long-term engine reliability and performance
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
9GT121113
The product you are viewing cross references to these numbers
- Porsche 996 TURBO 2000-05
- Porsche 997 MK1 GT3 2007-09
- Porsche 997 MKII GT3 2010-11
- Porsche 997 MKII Turbo 2010-13
- Porsche 997 MKII GT2 RS 2011-13
- Porsche 955 Cayenne S 4.5L V8 2003-06
- Porsche 955 Cayenne Turbo 4.5L 2003-06
- Porsche 955 Cayenne Turbo S 4.5L 2006>>
This Wahler Water Thermostat Insert is a Porsche 996 Turbo / 997 TT & GT3 / 955 Cayenne cooling system component designed to regulate coolant flow and maintain the engine at its optimal operating temperature. Installed within the thermostat housing, this insert automatically opens and closes according to coolant temperature, controlling circulation between the engine and radiator for efficient thermal management.
Fits:
- Porsche 996 TURBO 2000-05
- Porsche 997 MK1 GT3 2007-09
- Porsche 997 MKII GT3 2010-11
- Porsche 997 MKII Turbo 2010-13
- Porsche 997 MKII GT2 RS 2011-13
- Porsche 955 Cayenne S 4.5L V8 2003-06
- Porsche 955 Cayenne Turbo 4.5L 2003-06
- Porsche 955 Cayenne Turbo S 4.5L 2006>>
Diagram Ref No 7
What This Product Does:
- Regulates coolant flow through the cooling system
- Maintains optimal engine operating temperature
- Controls engine warm-up and cooling efficiency
- Helps prevent overheating and overcooling
- Supports fuel efficiency, emissions control, and engine performance
- Works with the radiator and water pump to maintain stable temperatures
Symptoms Of Wear Or Failure:
- Engine overheating Engine running too cool or taking too long to warm up
- Fluctuating temperature gauge readings
- Poor cabin heater performance
- Coolant leaks near the thermostat housing
- Reduced fuel efficiency caused by incorrect operating temperature
- Check engine light related to cooling system faults
Why Replacement Matters:
- Restores proper coolant circulation and temperature regulation
- Prevents overheating and potential engine damage
- Improves engine efficiency and fuel economy
- Ensures reliable heater and climate control operation
- Protects cooling system components from excessive stress and wear
- Maintains long-term engine reliability and performance
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610612573
The product you are viewing cross references to these numbers
- Porsche Boxster 987 MKII 2.9L 2009-12
- Porsche Boxster S 987 MKII 3.4L 2009-12
- Porsche 997 MKII Carrera C2 3.6L 2009-12
- Porsche 997 MKII Carrera C4 3.6L 2009-12
- Porsche 997 MKII Carrera C2S 3.8L 2009-12
- Porsche 997 MKII Carrera C4S 3.8L 2009-12
- Porsche 997 MKII Turbo 2010-13
- Porsche 991.1 GT3 3.8L (475 Bhp) 2014-16
- Porsche 991.1 GT3 RS 4.0L (500 Bhp) 2015-16
- Porsche Cayman 2.9L 987C MKII 2009-12
- Porsche Cayman S / R 3.4L 987C MKII 2009-12
This Wahler Water Pump Thermostat Insert is a Porsche 987.2 / 997.2 / 991.1 cooling system component designed to regulate coolant flow within the engine cooling circuit. Installed within the thermostat housing or water pump assembly, this thermostat insert opens and closes at predetermined temperatures to control coolant circulation between the engine and radiator.
Fits:
- Porsche Boxster 987 MKII 2.9L 2009-12
- Porsche Boxster S 987 MKII 3.4L 2009-12
- Porsche 997 MKII Carrera C2 3.6L 2009-12
- Porsche 997 MKII Carrera C4 3.6L 2009-12
- Porsche 997 MKII Carrera C2S 3.8L 2009-12
- Porsche 997 MKII Carrera C4S 3.8L 2009-12
- Porsche 997 MKII Turbo 2010-13
- Porsche 991.1 GT3 3.8L (475 Bhp) 2014-16
- Porsche 991.1 GT3 RS 4.0L (500 Bhp) 2015-16
- Porsche Cayman 2.9L 987C MKII 2009-12
- Porsche Cayman S / R 3.4L 987C MKII 2009-12
Diagram Ref No 21
What This Product Does:
- Regulates coolant flow through the engine cooling system
- Maintains optimal engine operating temperature
- Controls engine warm-up and cooling efficiency
- Works with the water pump to ensure effective coolant circulation
- Helps prevent overheating and overcooling
- Supports fuel efficiency and emissions performance
Symptoms Of Wear Or Failure:
- Engine overheating
- Engine running too cool or warming up slowly
- Fluctuating temperature gauge readings
- Poor heater performance inside the cabin
- Coolant leaks around the thermostat housing
- Reduced fuel economy caused by incorrect operating temperature
- Check engine light related to cooling system faults
Why Replacement Matters:
- Restores proper coolant flow and temperature regulation
- Prevents overheating and potential engine damage
- Improves engine efficiency and fuel economy
- Ensures reliable heater and climate control operation
- Protects cooling system components from excessive wear and stress
- Maintains long-term engine reliability and performance
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
9A110622503
The product you are viewing cross references to these numbers
- Porsche 928 4.5L 1978-82
- Porsche 928S 4.7L 1981-83
- Porsche 928S2 4.7L 1984-86
- Porsche 928S4 5.0L 1987-92
- Porsche 928GT 5.0L 1989-91
- Porsche 928GTS 5.4L 1992-95
This Wahler Thermostat is a Porsche 928 cooling system component designed to regulate engine coolant flow and maintain the correct operating temperature. Installed within the cooling circuit, the thermostat automatically opens and closes according to coolant temperature, ensuring efficient engine warm-up and stable cooling performance under all driving conditions.
Fits:
- Porsche 928 4.5L 1978-82
- Porsche 928S 4.7L 1981-83
- Porsche 928S2 4.7L 1984-86
- Porsche 928S4 5.0L 1987-92
- Porsche 928GT 5.0L 1989-91
- Porsche 928GTS 5.4L 1992-95
Diagram Ref No 21
What This Product Does:
- Regulates coolant circulation through the engine and radiator
- Maintains optimal engine operating temperature
- Controls engine warm-up and cooling efficiency
- Helps prevent overheating or overcooling
- Supports fuel efficiency, emissions control, and engine performance
Symptoms Of Wear Or Failure:
- Engine overheating
- Engine running too cool or taking excessive time to warm up
- Fluctuating temperature gauge readings
- Poor cabin heater performance
- Coolant leaks around the thermostat housing
- Reduced fuel efficiency due to incorrect operating temperature
- Check engine warning light related to cooling system faults
Why Replacement Matters:
- Restores proper coolant flow and temperature regulation
- Prevents overheating and potential engine damage
- Improves engine efficiency and fuel economy
- Ensures reliable heater and climate control operation
- Protects cooling system components from excessive wear and stress
- Maintains long-term engine performance and reliability
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
92810612917
The product you are viewing cross references to these numbers
- Porsche 944S2 3.0L 16V 1989-91
- Porsche 968 3.0L 1992-94
- Porsche 968 Sport 3.0L 1994-95
- Porsche 968 CS 3.0L 1993-95
- Porsche 968 Turbo S 3.0L 1993-94
This Wahler Sealing Ring For Thermostat is a Porsche 944 / 968 cooling system seal designed to provide a secure, leak-proof connection between the thermostat and thermostat housing. This sealing ring ensures proper coolant containment and pressure retention within the engine cooling system, helping maintain stable operating temperatures and efficient engine performance.
Fits:
- Porsche 944S2 3.0L 16V 1989-91
- Porsche 968 3.0L 1992-94
- Porsche 968 Sport 3.0L 1994-95
- Porsche 968 CS 3.0L 1993-95
- Porsche 968 Turbo S 3.0L 1993-94
Diagram Ref No 14
What This Product Does:
- Creates a leak-proof seal around the thermostat housing
- Prevents coolant leaks from the thermostat assembly
- Maintains correct cooling system pressure
- Supports efficient engine temperature regulation
- Ensures reliable thermostat operation and fitment
Symptoms Of Wear Or Failure:
- Coolant leaks around the thermostat housing
- Low coolant levels or frequent top-ups
- Engine overheating due to pressure loss
- Visible deterioration or flattening of the seal
- Coolant residue or staining near the thermostat area
- Reduced cooling system efficiency
Why Replacement Matters:
- Restores proper coolant sealing and pressure retention
- Prevents coolant leaks and overheating issues
- Ensures efficient thermostat operation
- Protects the engine from heat-related damage
- Helps avoid costly cooling system repairs
- Maintains OEM reliability and long-term performance
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
94410692908
The product you are viewing cross references to these numbers
- Porsche Boxster 986 2.5L 1997-99
- Porsche Boxster 986 2.7L 1999-02
- Porsche Boxster S 986 3.2L 1999-02
- Porsche Boxster 986 2.7L 2003-04
- Porsche Boxster S 986 3.2L 2003-04
- Porsche Boxster 987 2.7L 2005-08/08
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- Porsche 996 C2 3.4L 1997-08/01
- Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C2 3.6L 09/01-2005
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
- Porsche 997 MK1 TURBO 2007-09
- Porsche 997 MK1 GT3 2007-09
- Porsche 997 MK1 GT2 2007-09
This Water Thermostat Insert is a Porsche 986 / 987 / 996 / 997 cooling system component designed to regulate engine coolant flow and maintain optimal operating temperature. Installed within the thermostat housing, the insert opens and closes according to coolant temperature, controlling circulation between the engine and radiator.
Fits:
- Porsche Boxster 986 2.5L 1997-99
- Porsche Boxster 986 2.7L 1999-02
- Porsche Boxster S 986 3.2L 1999-02
- Porsche Boxster 986 2.7L 2003-04
- Porsche Boxster S 986 3.2L 2003-04
- Porsche Boxster 987 2.7L 2005-08/08
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- Porsche 996 C2 3.4L 1997-08/01
- Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C2 3.6L 09/01-2005
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
- Porsche 997 MK1 TURBO 2007-09
- Porsche 997 MK1 GT3 2007-09
- Porsche 997 MK1 GT2 2007-09
Diagram Ref No 6
What This Product Does:
- Regulates coolant flow through the engine cooling system
- Maintains optimal engine operating temperature
- Controls engine warm-up and cooling efficiency
- Helps prevent overheating or overcooling
- Supports fuel efficiency and emissions performance
Symptoms Of Wear Or Failure:
- Engine overheating
- Engine running too cool or taking too long to warm up
- Fluctuating engine temperature readings
- Poor heater performance inside the cabin
- Coolant leaks around the thermostat housing
- Reduced fuel efficiency due to improper temperature regulation
Why Replacement Matters:
- Restores proper coolant flow and temperature control
- Prevents overheating and potential engine damage
- Improves engine efficiency and fuel economy
- Supports correct heater and climate control operation
- Ensures long-term reliability of the cooling system and engine operation
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610612554
The product you are viewing cross references to these numbers
- Porsche 955 Cayenne 3.2L V6 2003-06

Fits:
Porsche 955 Cayenne 3.2L 2003-06
Click 'Zoom in' for large parts diagram.
Diagram ref no 2
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
95510611300
The product you are viewing cross references to these numbers
- Porsche Boxster 986 2.5L 1997-99
- Porsche Boxster 986 2.7L 1999-02
- Porsche Boxster S 986 3.2L 1999-02
- Porsche Boxster 986 2.7L 2003-04
- Porsche Boxster S 986 3.2L 2003-04
- Porsche Boxster 987 2.7L 2005-08/08
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- Porsche 996 C2 3.4L 1997-08/01
- Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C2 3.6L 09/01-2005
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
- Porsche Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
Fits:
Porsche 986 Boxster 1997-2004
Porsche 996 C2, C4
Porsche 987 Boxster 2005>>
Porsche 997 2005-08
Price includes new low temperature thermostat insert manufactured in Germany by one of the same manufacturers that makes the oe thermostat insert, allowing you to reuse your original housing. Provides increased cooling capacity increasing power while ensuring consistent performance and extending engine-component longevity.
Installation recommended only by trained Porsche technician or Porsche service department using genuine Porsche coolant.
Click 'Zoom in' for large parts diagram.
Diagram Ref No 5, 6 & 7
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610601361
The product you are viewing cross references to these numbers