Water pump thermostat insert. Porsche 997 GT3 RS 3.8L / 997 GT3 RS 4.0 2010–11 / 992.1 GT3 Cup 2021–24  ›  9GT121113A

Water pump thermostat insert
This genuine Porsche thermostat insert fits within the water pump / cooling system housing and helps regulate coolant flow through the engine and radiator circuit.

Fits

• Porsche 997 GT3 3.8L 2009 - 2011 M97.77
• Porsche 997 GT3 RS 4.0L 2010 - 2011 M97.74
  
  
• Porsche 992.1 GT3 Cup 4.0L 2021–24
  
  

Diagram ref no 8

What This Product Does

As coolant temperature changes, the thermostat adjusts circulation within the cooling circuit. Its operation manages warm-up and the subsequent flow needed to control engine temperature. The insert works inside the associated housing; it is not a radiator or water pump.

Functions

• Adjusts coolant circulation in response to temperature.
• Manages cooling-circuit flow while the engine warms.
• Contributes to temperature control once the engine is warm.

Technical Details

• Genuine Porsche component: 9GT121113A.
• Internal diagram descriptions identify it as a thermostat insert and thermostat.
• The 997 assembly covers M97.77 applications for 2010–11 and the M97.74 GT3 RS 4.0 for 2011.
• The additional engine-water-circuit diagram covers the 2021 911 (992) GT3 Cup.
• Surrounding housings, sealing rings and O-rings have separate diagram entries.

Symptoms of Fault

• Abnormally high or inconsistent engine temperature.
• Cooling-system warnings, steam or coolant loss.
• Dampness or dried coolant deposits near housing joints.
• Gurgling associated with air or insufficient coolant.

These signs can also arise from other cooling components, so diagnosis should establish the cause before the insert is replaced.

Why Replacement Matters

Incorrect thermostat operation can disrupt temperature control. Renewing an insert with a confirmed fault addresses that component rather than masking a wider cooling-system problem. During the repair, examine the housing and its separate seals for deterioration, and establish which additional components the job requires.

FAQs

• Does the insert include its housing?
  The supplied diagrams show distinct housing components alongside the thermostat. Do not assume those components are included.
• Are sealing components identified separately?
  Yes. O-rings and sealing rings appear as individual entries in the associated assemblies.
• What information is needed to confirm suitability?
  Use 9GT121113A together with the vehicle model, production year, engine identification and corresponding parts diagram. For the Cup application, confirm the motorsport vehicle specification.

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

9GT121113A

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