Coolant Hoses - Centre Section
 Water coolant middle section pipe kit. Porsche 996 C4 3.4L / 3.6L
                        
                    
            
            
                    Water coolant middle section pipe kit. Porsche 996 C4 3.4L / 3.6L
                    - Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005
Fits:
Porsche 996 C4 3.4L / 3.6L
Kits comes with both supply and return hoses, breather pipes and all clips
Diagram ref: #10, #11, #5, #6, #23
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WATERPIPEKIT996C4
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This kit is comprised of the following items:
 Breather hose. Porsche 986 Boxster / 996
                        
                    
            
            
                    Breather hose. Porsche 986 Boxster / 996
                     
            
            
                    - 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 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04

Fits:
Porsche 986 Boxster 1997-04
Porsche 996 3.4L / 3.6L Carrera 1997-05
Porsche 996 GT3 3.6L 1999-05
Click 'Zoom in' for large parts diagram.
Diagram ref no 23
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99610613556
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                     Breather line water cooling system. Porsche 986 Boxster / 996
                        
                    
            
            
                    Breather line water cooling system. Porsche 986 Boxster / 996
                     
            
            
                    - 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 GT2 2001-05
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04

Fits:
Porsche 986 Boxster - 1997 to 2004
Porsche 996 - 1997 to 2005
Porsche 996 GT3 - 1999 to 2005
Click 'Zoom in' for large parts diagram.
Diagram ref no 16
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99610612754
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                     Breather Line. Porsche 996 Carrera / Turbo 1998-05
                        
                    
            
            
                    Breather Line. Porsche 996 Carrera / Turbo 1998-05
                     
            
            
                    - 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
Renew the ventilation path on your Porsche 911 (996-series) with these genuine breather / vent hoses. Designed for 1998-2005 911 (996) models (including Carrera, Turbo variants) these hoses ensure your engine’s breather or cooling-vent line operates correctly—preventing vapour or pressure buildup, supporting correct engine ventilation and maintaining system reliability.
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
Diagram Ref No 21 And 22
What This Product Does:
- In the context of the engine / cooling / ventilation system, a “breather line” or “vent hose / vent line” allows controlled venting of crankcase or cooling system gases, or supports the cooling/overflow/expansion system to relieve pressure, direct vapour, or provide required venting.
- These hoses ensure air or vapour that builds up is not trapped in the engine/cooling system, allow system pressure to stabilise, and maintain correct service behaviour of the engine’s ventilation or cooling circuits.
- They also help prevent buildup of pressure/vapour that could otherwise lead to malfunction, leaks or driveability issues.
Symptoms Of Wear, Damage Or When To Replace:
- Hose visible damage, cracking, brittleness or detachment — Over time, heat and age degrade rubber/hose materials.
- Engine or cooling system venting issues — for example, if you smell vapour/odour, see coolant or oil vapour escaping in unusual places, or lid caps popping off unexpectedly.
- Unusual noise or hissing from the engine bay or venting hose areas—possibly indicating a leak or damaged hose.
- Performance degradation in the ventilation/cooling system—such as elevated temperatures, pressure spikes in cooling, or increased oil consumption if the hose is a crankcase breather.
- Poor condition hoses in older vehicles—since these parts are often overlooked in maintenance, especially with older 996 models, they may be degraded and benefit from preventive replacement.
- Maintains correct system function: A properly functioning breather line ensures your engine’s ventilation/cooling systems are working as intended — preventing pressure buildup, vapour trapping or system inefficiencies.
- Prevents secondary damage: A failing hose might lead to undue pressure or vapour escaping in unwanted places, which can damage hoses, connectors, engine seals or other vulnerable parts.
- Helps reliability and longevity: Especially in older 996 models, replacing old, brittle, cracked hoses with fresh OEM-spec units avoids failures that can strand the vehicle or lead to more expensive repair.
- Peace of mind & maintenance value: Ensuring the ventilation path is intact supports the overall health of the engine and cooling system, which can matter for resale or restoration quality.
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99610676
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                     Cooling water pipe, feed. Porsche 996 C4 / 996 Turbo
                        
                    
            
            
                    Cooling water pipe, feed. Porsche 996 C4 / 996 Turbo
                     
            
            
                    - Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005
- Porsche 996 TURBO 2000-05

Fits:
Porsche 996 C4 3.4L / 3.6L 1998-05
Porsche 996 Turbo 2001-05
Click 'Zoom in' for large parts diagram.
Diagram ref no 12
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99610675203
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                     Water coolant pipe FEED. Porsche 986 Boxster S / 996
                        
                    
            
            
                    Water coolant pipe FEED. Porsche 986 Boxster S / 996
                     
            
            
                    - Porsche Boxster S 986 3.2L 1999-02
- 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
Fits:
Porsche 986 Boxster S - 1999 to 2004
Porsche 996 - 1997 to 2005
Porsche 996 turbo - 2001 to 2005
Porsche 996 GT3 - 2000 to 2004
Diagram ref no 1
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99610661153
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                     Water Pipe, Return. Porsche 986 Boxster S / 996 Carrera / GT2 / GT3 1999-05
                        
                    
            
            
                    Water Pipe, Return. Porsche 986 Boxster S / 996 Carrera / GT2 / GT3 1999-05
                     
            
            
                    - Porsche Boxster S 986 3.2L 1999-02
- 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 GT2 2001-05
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
Sold Each.
Fits:
Porsche 986 Boxster S 3.2L 1999>>2004
Porsche 996 Carrera 3.4L / 3.6L 1998>>2005
Cars With Engine Codes:
M96.01 / M96.02 / M96.03 / M96.04
Porsche 996 GT2 2001>>2005
Porsche 996 GT3 1999>>2005
Cars With Engine Codes:
M96.76 / M96.79
Diagram Ref No 7
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99610661554
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                    Coolant Hoses – Centre Section | Reliable Cooling for Porsche Performance
The centre section coolant hoses are vital components of your Porsche’s engine cooling system, responsible for circulating coolant between the front and rear of the vehicle. These hoses maintain consistent coolant flow through the radiator and engine, ensuring optimal temperature regulation and preventing overheating — essential for both performance and longevity.
At Design911, we supply a full range of genuine and high-quality coolant hoses in the centre section for Porsche models including 911, Boxster, Cayman. Each hose is engineered to deliver factory-accurate fitment, high heat resistance, and long-lasting durability under the extreme pressures of Porsche’s high-performance cooling systems.
What Do Centre Section Coolant Hoses Do?
Coolant hoses act as the lifelines of your Porsche’s cooling
system. The centre section hoses connect key parts of the cooling
circuit, helping to:
- Transfer
     coolant between the engine, radiator, and water pump.
 
- Regulate
     engine temperature during all driving conditions.
 
- Maintain
     system pressure for consistent cooling performance.
 
- Prevent overheating and protect the engine from thermal stress.
Their design ensures smooth, efficient coolant flow — especially important in Porsche models with long mid- or rear-engine coolant routing systems.
Why Do Coolant Hoses Fail?
Over time, coolant hoses are exposed to constant pressure,
high temperatures, and fluid corrosion. This can lead to:
- Rubber degradation or cracking from heat cycling.
- Coolant leaks due to worn hose ends or clamps.
- Swelling or soft spots caused by chemical breakdown.
- Abrasion damage from contact with nearby components.
- Age-related hardening, reducing flexibility and sealing strength.
Common signs of hose failure include visible cracks, coolant puddles under the car, engine temperature fluctuations, or low coolant levels.
Why Replace Faulty Coolant Hoses?
A weakened or leaking coolant hose can quickly lead to overheating, engine damage, or complete coolant loss. Replacing worn hoses ensures your Porsche’s cooling system operates safely and efficiently.
Benefits of replacement include:
- Restored, leak-free coolant circulation.
- Improved temperature control and engine protection.
- Prevention of overheating and costly repairs.
- Manufacturer-quality construction and precision fit.
All hoses in this range are made from high-performance rubber compounds and reinforced materials, designed to meet exacting standards for flexibility, strength, and heat resistance.
 
 
         
                
                
                    
 
                                     
                                     
                 
                 
                 
                 
                 
                 
                 
                