Coolant Return Hose. Porsche 997.1 Carrera 2005-08  ❭  99710683204

Coolant Return Hose, Return hose at the thermostat housing.
This original Porsche coolant hose forms part of the engine cooling system, helping return coolant through the cooling circuit and maintain correct engine operating temperature.

Fits:
Porsche 997.1  C2 / C2S 2005 - 2008
Porsche 997.1  C4 / C4S 2005 - 2008

Diagram ref no 15

This hose is used in the water pump / thermostat housing area on selected Porsche 997.1 models.

What This Part Does / Functions:
•  Routes coolant through the return side of the cooling system
•  Connects at the thermostat housing area where specified
•  Helps maintain correct coolant circulation and engine temperature control
•  Supports proper cooling system pressure and flow
•  Replaces a cracked, swollen, leaking or heat-damaged original hose
•  Helps prevent coolant loss and overheating risk
•  Provides correct Genuine Porsche hose shape, material and connection fitment
•  Supports reliable factory cooling system performance.

Why Replace This Part?
Coolant hoses are exposed to heat cycles, coolant pressure, engine bay temperatures, vibration and age-related rubber deterioration. Over time, the hose can harden, swell, crack, split or leak. A failing coolant return hose may cause coolant loss, low coolant warnings, overheating risk or visible coolant residue around the thermostat housing.

Replacing it with a Genuine Porsche coolant return hose helps restore the correct factory coolant routing and reliable cooling system sealing.

Common Symptoms of a Faulty Coolant Return Hose
•   Coolant leak around the thermostat housing
•   Dried coolant residue around the hose connections
•   Low coolant warning
•   Coolant smell from the rear engine bay
•   Engine temperature rising above normal
•   Hose swelling, cracking or softening
•   Cooling system pressure loss
•   Damage found during cooling system inspection.

When to Replace This Part
•   If the original hose is cracked, swollen, leaking or damaged
•   During thermostat housing or water pump service
•   During cooling system overhaul
•   When replacing related coolant pipes, hoses or clamps
•   If coolant loss is traced to the return hose
•   After engine bay service where the hose has been disturbed
•   If the hose has become brittle, soft or oil-contaminated

Where It Fits on the Car
This hose fits in the engine cooling / water cooling system at the thermostat housing area. It is identified as the coolant return hose / water hose return line and is shown in Porsche cooling diagrams as diagram reference no. 15.

 Correct routing, clamp positioning and sealing are important to prevent coolant leaks and maintain proper cooling system operation.

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

99710683204

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