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- Accessories
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The Porsche Drain Hose for Coolant Reservoir is a genuine OEM component that ensures your cooling system operates efficiently under all conditions. This hose connects the coolant reservoir to the overflow system, allowing excess coolant to safely flow into the expansion tank when system pressure rises.
Fits:
- 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 996 TURBO 2000-05
- Porsche 996 GT2 2001-05
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 997 Carrera 2 3.6L 2005-08
- Porsche 997 Carrera 2S 3.8L 2005-08
- Porsche 997 Carrera 4 3.6L 2005-08
- Porsche 997 Carrera 4S 3.8L 2005-08
- Porsche 997 TURBO 2007-09
- Porsche 997 GT3 2007-09
- Porsche 997 GT2 2007-09
- 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 GT3 2010-11
- Porsche 997 MKII Turbo 2010-13
- Porsche 997 MKII GT2 RS 2011-13
What This Product Does:
This hose functions as a drain / overflow path in the cooling system. When coolant pressure or volume is high (due to heat, expansion), excess coolant flows into the reservoir or overflow tank via this hose.
Symptoms / Signs Of A Faulty / Damaged Hose:
- Coolant leaks (weeping or dripping) around the reservoir, hose connection points, or under the car.
- Overheating or fluctuating temperatures, if coolant isn’t flowing properly or the overflow path is blocked.
- Loss of coolant in the reservoir over time, without other visible leaks.
- A hose that is cracked, brittle, perished, or has collapsed (blocking flow).
- Bubbling or gurgling noises in the cooling system or reservoir due to trapped air or improper overflow.
- Overflow tank that doesn’t fill or returns little coolant on cooling — i.e., the system is not cycling properly through the reservoir.
Why Replacement Matters:
- Ensures the overflow system works correctly — letting excess coolant go to the reservoir instead of causing pressure issues or spillage.
- Prevents coolant loss or leaks, which can lead to engine damage from low coolant or overheating.
- Maintains system pressure balance, which is critical in modern closed-loop cooling systems for proper pump flow and temperature control.
- Avoids damage to other parts — a leaking hose can spray coolant onto other components (belts, wiring, bodywork) causing corrosion or damage.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610629705
The product you are viewing cross references to these numbers
- 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 996 TURBO 2000-05
- Porsche 996 GT2 2001-05
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- 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
- 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 GT3 2010-11
- Porsche 997 MKII Turbo 2010-13
- Porsche 997 MKII GT2 RS 2011-13
Shop Securely
12 Month Warranty
Worldwide Delivery
Fits:
Porsche 996 1998-05
Porsche 997 MKI 2005>>
Porsche 986 Boxster 1997-04
Porsche 987 Boxster 2005>>
Porsche 987C Cayman 2005>>
Click 'Zoom in' for large parts diagram.
Diagram ref no 11
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99970737040
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 996 TURBO 2000-05
- Porsche 996 GT2 2001-05
- 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
- Porsche Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
Shop Securely
12 Month Warranty
Worldwide Delivery
Fits:
Porsche 996 1998-05
Porsche 997 MKI 2005>>
Porsche 986 Boxster 1997-04
Porsche 987 Boxster 2005>>
Porsche 987C Cayman 2005>>
Click 'Zoom in' for large parts diagram.
Diagram ref no 12
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99970737140
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 996 TURBO 2000-05
- Porsche 996 GT2 2001-05
- 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
- Porsche Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
Shop Securely
12 Month Warranty
Worldwide Delivery
Fits:
Porsche 986 Boxster 1997-04
Porsche 996 1998-05
Porsche 996 Turbo 2001-05
Porsche 996 GT3 1999-05
Porsche Carrera GT 2003-06
Click 'Zoom in' for large parts diagram.
Diagram ref no 3
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99652860500
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 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 996 TURBO 2000-05
- Porsche 996 GT2 2001-05
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche Carrera GT
Shop Securely
12 Month Warranty
Worldwide Delivery
Coolant Bottles / Expansion Tanks – Reliable Cooling Performance for Porsche Vehicles
Coolant bottles (also known as expansion tanks) are a vital part of your Porsche’s cooling system. They store excess coolant and manage pressure fluctuations as the engine heats up and cools down. By maintaining proper coolant levels and system pressure, they help prevent overheating, engine damage, and coolant loss - ensuring optimal performance and reliability.
At Design911, we offer a complete range of genuine and quality coolant bottles and expansion tanks for Porsche models including 911, Boxster, Cayman, Cayenne, Macan, and Panamera. Each tank is designed to deliver exact fitment, superior material strength, and long-term resistance to heat and pressure - matching the quality and precision of factory components.
What Do Coolant Bottles / Expansion Tanks Do?
The coolant bottle or expansion tank works as part of a
sealed cooling system to:
- Store
and regulate excess coolant as temperatures and pressure fluctuate.
- Maintain
consistent pressure to prevent overheating or boiling.
- Allow
coolant recovery as the system cools, keeping the radiator full.
- Provide a visible level indicator to monitor coolant condition and volume.
A properly functioning expansion tank ensures your engine operates at a stable temperature, improving efficiency and extending engine life.
Why Do Coolant Bottles Fail?
Coolant bottles are constantly exposed to heat, vibration,
and pressure, which can cause degradation over time. Common causes of failure
include:
- Plastic
fatigue or cracking from thermal cycling.
- Coolant
leaks around seams, caps, or hose connections.
- Discolouration
or brittleness from age and coolant exposure.
- Faulty
pressure caps leading to loss of system pressure.
- Corrosion or contamination inside the tank.
Symptoms of a failing coolant bottle include visible coolant leaks, low coolant warnings, overheating, or pressure loss within the cooling system.
Why Replace Faulty Coolant Bottles / Expansion Tanks?
A damaged or leaking expansion tank can quickly lead to overheating, engine damage, or complete cooling system failure. Replacing it ensures safe, efficient operation and protects vital engine components.
Benefits of replacement include:
- Restored coolant capacity and pressure stability.
- Prevention of leaks and overheating.
- Enhanced cooling system reliability and engine protection.
- Factory-spec construction with manufacturer-level durability.
All replacement tanks are designed to meet or exceed factory standards using high-grade materials that resist cracking, corrosion, and deformation under extreme conditions
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