Coolant Hoses - Centre Section

HVAC Heater Hose - Feed

Maintain the efficiency and reliability of your Porsche's heating and cooling system with this HVAC Heater Hose (Feed)

Fits:

• Porsche 996 C2 3.6L 09/01-2005 (Tiptronic only)                 
• Porsche 996 C4 3.6L 09/01-2005 (Tiptronic only)     
• Porsche 996 C4S 3.6L 09/01-2005 (Tiptronic only)     
• Porsche 996 TURBO 2000-05
• 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 GT2 2007-09
• Porsche 997 MKII GT3 / GT3 RS 2010-11

Diagram ref no 17 

This genuine Porsche coolant hose forms an important part of the vehicle's HVAC (Heating, Ventilation and Air Conditioning) system by carrying hot engine coolant from the engine to the heater matrix (heater core). As coolant flows through the heater matrix, warm air is produced and directed into the cabin, providing rapid demisting, comfortable interior temperatures and helping the climate control system operate as designed.

Manufactured to Porsche's exact specifications, this Genuine Porsche heater feed hose offers the correct internal diameter, moulded shape and heat-resistant construction to ensure perfect fitment, unrestricted coolant flow and long-term reliability.

Whether replacing a leaking hose or carrying out preventative maintenance during cooling system repairs, choosing Genuine Porsche components ensures the quality and durability expected from the original factory installation.

What Does the HVAC Heater Feed Hose Do?

The heater feed hose transports hot coolant from the engine's cooling system to the heater matrix located inside the dashboard.

As engine coolant passes through the heater matrix, air is blown across it by the HVAC system, providing:

• Warm cabin heating
• Rapid windscreen demisting and defrosting
• Stable interior temperature control
• Efficient operation of the Porsche climate control system

The hose must withstand constant exposure to high coolant temperatures and system pressure while remaining flexible enough to accommodate engine movement and thermal expansion.

Why Do Heater Hoses Fail?

Like all rubber coolant hoses, heater hoses gradually deteriorate through age and continual exposure to heat, pressure and coolant chemicals.

Common causes of failure include:

• Rubber hardening with age
• Internal deterioration from coolant additives
• Heat cycling causing loss of flexibility
• Surface cracking and perishing
• Abrasion against surrounding components
• Swelling from oil or coolant contamination
• Corrosion around hose connections

As the hose ages, it becomes more susceptible to splitting or developing leaks, which can lead to coolant loss, reduced heater performance and, if ignored, engine overheating.

When Should the Heater Hose Be Replaced?

The HVAC heater feed hose should be inspected during every major service or whenever the cooling system is being maintained.

Replacement is recommended if you notice:

• Coolant leaks
• Dampness around the hose connections
• Cracked or perished rubber
• Bulging or swollen sections
• Soft or excessively hard hose material
• Sweet coolant smell from the engine bay
• Poor cabin heating caused by coolant loss
• During cooling system overhauls or engine-out servicing

Replacing ageing coolant hoses as preventative maintenance greatly reduces the risk of unexpected coolant loss and helps maintain the reliability of the engine and heating system.

Genuine Porsche Cooling & HVAC Components

The cooling and heating systems on your Porsche are designed to work together to regulate both engine temperature and cabin comfort. Every hose within the system plays an essential role in maintaining efficient coolant circulation and ensuring reliable operation under all driving conditions.

Because rubber coolant hoses naturally age over time, replacing them before failure is one of the most effective forms of preventative maintenance. A genuine Porsche hose guarantees the correct fit, material specification and durability required to withstand the demanding operating conditions of a high-performance engine.

Whether you're refreshing an ageing cooling system or undertaking a complete engine rebuild, fitting Genuine Porsche hoses provides peace of mind and helps preserve the long-term reliability of your vehicle.

Benefits of Replacing the Heater Feed Hose

• Restores reliable coolant circulation
• Improves cabin heating performance
• Supports rapid windscreen demisting
• Reduces the risk of coolant leaks
• Helps protect against engine overheating
• Direct Genuine Porsche replacement
• Ideal during cooling system servicing or preventative maintenance        

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

99610621275

The product you are viewing cross references to these numbers

HVAC Heater Feed Hose – Feed

Restore the reliability of your Porsche's cooling and heating system with this OE Heater Feed Hose.

Fits:

• Porsche 996 C2 3.6L 09/01-2005 (Tiptronic only)          
• Porsche 996 C4 3.6L 09/01-2005 (Tiptronic only)     
• Porsche 996 C4S 3.6L 09/01-2005 (Tiptronic only)     
• Porsche 996 TURBO 2000-05
• 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 GT2 2007-09
• Porsche 997 MKII GT3 / GT3 RS 2010-11

Diagram ref no 17 

Designed to meet or exceed original equipment specifications, this high-quality replacement hose carries hot engine coolant from the engine to the heater matrix (heater core), enabling the HVAC system to provide efficient cabin heating, rapid windscreen demisting and consistent climate control performance.

Manufactured from premium automotive-grade rubber with reinforced construction, this OE Match hose is engineered to withstand the high temperatures, pressures and continual thermal cycling experienced within the Porsche cooling system. Offering excellent fitment and long-term durability, it provides an ideal replacement for ageing or deteriorated original hoses at a competitive price.

Whether you're repairing a coolant leak, refreshing the cooling system or carrying out preventative maintenance, replacing worn heater hoses helps maintain the reliability and efficiency of your Porsche.

What Does the Heater Feed Hose Do?

The heater feed hose forms part of the engine's coolant circuit, carrying heated coolant from the engine to the heater matrix located within the dashboard.

As warm coolant flows through the heater matrix, the vehicle's blower motor forces air across it before directing the heated air into the cabin. This allows the system to provide:

• Efficient interior heating
• Rapid windscreen demisting and defrosting
• Consistent climate control performance
• Comfortable cabin temperatures throughout colder months

Although relatively simple in design, the heater feed hose plays a vital role in both passenger comfort and the overall operation of the cooling system.

Why Do Heater Feed Hoses Fail?

Heater hoses operate in one of the harshest environments on the vehicle, continually exposed to high coolant temperatures, pressure fluctuations and engine vibration.

Over many years of service, the rubber gradually deteriorates due to:

• Constant heating and cooling cycles
• Age-related hardening and loss of flexibility
• Internal degradation caused by coolant additives
• Surface cracking and perishing
• Swelling from contamination
• Fatigue around hose ends and retaining clips
• Abrasion against surrounding engine components

As deterioration progresses, small coolant leaks can develop before eventually leading to hose failure and rapid coolant loss.

When Should the Heater Feed Hose Be Replaced?

Because coolant hoses naturally age over time, Porsche specialists often recommend inspecting them during every major service and replacing them whenever significant cooling system work is undertaken.

Replacement is advised if you notice:

• Visible coolant leaks or staining
• Cracked, brittle or hardened rubber
• Bulging or swollen sections
• Dampness around hose connections
• A sweet coolant smell after driving
• Reduced cabin heating performance
• During engine-out repairs or cooling system refurbishment
• As preventative maintenance on older vehicles

Replacing ageing heater hoses before they fail can help prevent unexpected coolant loss, reduce the risk of engine overheating and avoid costly roadside breakdowns.

Porsche Cooling System & Heater Hoses

The cooling system on your Porsche does far more than regulate engine temperature. It also supplies heated coolant to the HVAC system, ensuring efficient cabin heating, effective windscreen demisting and year-round driving comfort.

As rubber hoses age, they gradually lose their elasticity and structural integrity, making them increasingly susceptible to leaks and sudden failure. Replacing heater hoses as part of routine maintenance is a sensible investment that helps maintain the integrity of the entire cooling system while reducing the risk of overheating caused by coolant loss.

OE Match replacement hoses are manufactured to provide factory-style fitment, dependable performance and excellent value, making them ideal for both routine servicing and complete cooling system overhauls.

Benefits of Replacing the Heater Feed Hose

Restores reliable coolant circulation Maintains efficient cabin heating Improves windscreen demisting performance Reduces the risk of coolant leaks Helps protect against engine overheating OE Match quality with factory-style fitment Ideal for preventative maintenance on ageing vehicles

Whether you're carrying out a routine service, repairing a coolant leak or restoring your Porsche to its original condition, Design911 supplies the trusted parts you need to keep your vehicle performing at its best.

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

99610621275

The product you are viewing cross references to these numbers

O-ring – 46.7 x 3.53 – used in various applications within the car's cooling system.

Fits:
Porsche 987 Boxster 2005-12
Porsche 987 Cayman 2006-12

Porsche 981 Boxster 2012-16 
Porsche 981 Boxster Spyder 2016 
Porsche 981 Cayman 2014-16 
Porsche 981 Cayman GT4 2016 

Porsche 718 (982) Boxster 2017>> 
Porsche 718 (982) Boxster Spyder 2019>>
Porsche 718 (982) Cayman 2017>>
Porsche 718 (982) Cayman GT4 2019>>

Porsche 996 GT3 / RS 1999-05
Porsche 996 Turbo / GT2 2001-05

Porsche 997 Carrera 2005-12
Porsche 997 Turbo / GT2 RS 2007-13
Porsche 997 GT3 / RS 2007-11

Porsche 991 Carrera 2012-19
Porsche 991 Turbo / GT2 RS 2014-20
Porsche 991 GT3 / RS 2014-21

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

99610680103

The product you are viewing cross references to these numbers

O-ring – 46.7 x 3.53 – used in various applications within the car's cooling system.

Fits:
Porsche 987 Boxster 2005-12
Porsche 987 Cayman 2006-12

Porsche 981 Boxster 2012-16 
Porsche 981 Boxster Spyder 2016 
Porsche 981 Cayman 2014-16 
Porsche 981 Cayman GT4 2016 

Porsche 718 (982) Boxster 2017>> 
Porsche 718 (982) Boxster Spyder 2019>>
Porsche 718 (982) Cayman 2017>>
Porsche 718 (982) Cayman GT4 2019>>

Porsche 996 GT3 / RS 1999-05
Porsche 996 Turbo / GT2 2001-05

Porsche 997 Carrera 2005-12
Porsche 997 Turbo / GT2 RS 2007-13
Porsche 997 GT3 / RS 2007-11

Porsche 991 Carrera 2012-19
Porsche 991 Turbo / GT2 RS 2014-20
Porsche 991 GT3 / RS 2014-21

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

99610680103

The product you are viewing cross references to these numbers

Transverse Coolant Breather Line. 

The Genuine Porsche Transverse Coolant Breather Line (Part Number 99710676702) is an important engine cooling system component designed to help maintain effective coolant circulation, air removal and reliable cooling system operation on compatible Porsche models.

Fits:

• Porsche Boxster 987 2.7L 2005-08/08
• Porsche Boxster 987 S 3.2/3.4L 2005-08/08
• Porsche Boxster 987 MKII 2.9L 2009-12
• Porsche Boxster S 987 MKII 3.4L 2009-12
• 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 / GT3 RS 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 / GT3 RS 2010-11
• Porsche 997 MKII Turbo 2010-13
• Porsche 997 MKII GT2 RS 2011-13
• Porsche Cayman 2.7L 987C 2006-08
• Porsche Cayman S 3.4L 987C 2005-08
• Porsche Cayman 2.9L 987C MKII 2009-12
• Porsche Cayman S / R 3.4L 987C MKII 2009-12  

Diagram Ref No 13

Manufactured to Porsche's original equipment specifications, this transverse breather line forms part of the vehicle's coolant ventilation circuit, providing a dedicated passage for air and coolant to move between the relevant cooling system components.

The engine cooling system relies on an effective network of coolant pipes, hoses and ventilation lines to maintain consistent operating temperatures. Air trapped within the cooling circuit can interfere with coolant circulation, reduce heat transfer efficiency and contribute to localised hot spots.

The transverse coolant breather line helps provide the intended ventilation path within the cooling system, supporting the removal of trapped air and the correct distribution of coolant throughout the circuit.

Positioned within the vehicle's cooling system pipework, the line is designed to withstand normal coolant system pressure, temperature fluctuations and vibration.

Over time, the original breather line may become damaged, cracked, corroded or weakened due to ageing, exposure to heat, repeated temperature changes or mechanical stress. A leaking or restricted breather line may contribute to coolant loss, ineffective air removal and cooling system performance problems.

Replacing a damaged or deteriorated transverse coolant breather line with a Genuine Porsche component helps restore the original ventilation arrangement, maintain cooling circuit integrity and support reliable engine temperature regulation.

Ideal for cooling system repairs, coolant leak diagnosis, radiator pipework maintenance, engine servicing and preventative maintenance.

What This Product Does:
The transverse coolant breather line forms part of the engine's cooling system ventilation circuit and performs several important functions.

• Supports Cooling System Ventilation: Provides a passage for air and coolant within the designated cooling system vent circuit.
• Helps Remove Trapped Air: Allows air to migrate through the designed ventilation path, reducing the likelihood of air pockets forming within the cooling system.
• Supports Coolant Circulation: Helps maintain the conditions required for consistent coolant movement throughout the engine cooling circuit.
• Maintains Cooling System Integrity: Provides a sealed connection between the relevant cooling system components.
• Supports Engine Temperature Regulation: Helps the cooling system operate efficiently by maintaining its intended coolant ventilation arrangement.
• Reduces Airlock Risk: Supports the removal of trapped air that could interfere with coolant circulation after servicing or coolant replacement.
• Accommodates Normal System Pressure: Designed to operate under the normal temperature and pressure conditions of the vehicle's cooling system.
• Supports Cooling System Bleeding: Provides part of the intended air removal pathway when the cooling system is filled and bled according to Porsche procedures.
• Helps Protect Engine Components: Supports reliable cooling system operation, reducing the risk of problems associated with insufficient coolant circulation.
• Maintains Original Equipment Fitment: Replaces the original transverse breather line using the specified factory routing and connections.

Symptoms Of Wear Or Failure:
Cooling system breather lines are exposed to coolant, temperature changes, vibration and environmental conditions throughout their service life.

Over time, material deterioration, physical damage or corrosion may compromise the line or its connections.

Common symptoms of a worn or failing transverse coolant breather line include:

• Coolant Leakage: Visible coolant dripping or seeping from the breather line, its fittings or connection points.
• Low Coolant Level: Repeated coolant top-ups may indicate a leak within the breather line or another part of the cooling circuit.
• Visible Cracks or Splits: Damage to the pipe or its connecting sections may allow coolant to escape.
• Corrosion or Surface Deterioration: Ageing and environmental exposure may weaken the line or its fittings.
• Damaged or Loose Connections: Worn connectors, retaining clips or seals may prevent the line from remaining securely attached.
• Dried Coolant Deposits: White, pink or coloured residue around the line may indicate previous coolant seepage.
• Coolant Warning Messages: Significant coolant loss may activate the vehicle's low coolant warning.
• Engine Overheating: Coolant loss or ineffective removal of trapped air may contribute to higher-than-normal engine temperatures.
• Air Trapped in the Cooling System: A restricted or incorrectly connected vent line may contribute to persistent air pockets.
• Unusual Cooling System Noises: Gurgling or bubbling noises may occur when air remains trapped within the coolant circuit.
• Coolant Smell: Escaping antifreeze may produce a noticeable sweet smell around the vehicle.
• Physical Damage Following Repairs: Incorrect handling, accidental impact or improper installation may damage the breather line.
• Blocked or Restricted Vent Passage: Debris or internal deterioration may obstruct the intended air and coolant ventilation path.

Why Replacement Matters:
Replacing a cracked, leaking or damaged transverse coolant breather line is important for maintaining reliable cooling system operation and protecting the engine against excessive temperature.

Key Benefits of Replacement:

• Restores Cooling System Ventilation: Helps maintain the original air removal pathway within the coolant circuit.
• Reduces the Risk of Airlocks: Supports effective removal of trapped air that can interfere with coolant circulation.
• Helps Prevent Coolant Leaks: Replaces damaged lines or connections that allow coolant to escape.
• Supports Efficient Engine Cooling: Helps maintain the conditions required for effective coolant circulation and heat transfer.
• Reduces Overheating Risk: Restoring a leaking or restricted line can help address cooling system problems that may contribute to elevated engine temperatures.
• Maintains Cooling System Pressure Integrity: Provides the specified sealed connection within the cooling circuit.
• Supports Reliable Coolant Bleeding: Helps maintain the intended ventilation route during coolant refilling and servicing.
• Protects Engine Components: Reduces the risk of overheating-related damage caused by unresolved cooling system faults.
• Genuine Porsche Quality: Manufactured to the original equipment specification for compatible vehicles.
• Correct Factory Routing: Designed to match the intended transverse breather line position and connection arrangement.
• Supports Long-Term Cooling System Reliability: Helps prevent recurring problems caused by damaged or deteriorated ventilation pipework.
• Ideal During Cooling System Repairs: Suitable for replacement when surrounding coolant pipes or hoses are being serviced.
• Supports Preventative Maintenance: Allows ageing or damaged cooling system components to be replaced before more significant failures develop.

Although the transverse coolant breather line is a relatively small part of the complete cooling system, it performs an important function in maintaining the intended ventilation arrangement.

A damaged or leaking breather line can allow coolant to escape and may interfere with the cooling system's ability to remove trapped air effectively.

Persistent coolant loss or air pockets can reduce heat transfer efficiency and contribute to overheating, potentially placing additional thermal stress on the engine.

Replacing the defective line with a Genuine Porsche component helps restore the factory cooling system configuration and support dependable engine operation.

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

99710676702

The product you are viewing cross references to these numbers

Water coolant hose, supply
OE Match coolant supply hose for selected Porsche 997.1 and 997.2 models. This replacement carries coolant along the supply circuit and provides an alternative to the original Porsche component.

Fits:
Porsche 997.1 2005 - 2008
Porsche 997.2 2009 - 2012

Diagram ref no 17

What This Product Does

The hose joins designated connections within the water-cooling supply circuit. Its role is to carry coolant between those connections, supporting circulation and temperature management. OE Match develops replacement components around Porsche applications, with specification review and sample evaluation forming part of its approval process.

Functions

• Carries coolant along the designated supply route.
• Links the relevant cooling-circuit connections.
• Supports a sealed fluid path when properly fitted.

Technical Details

• Brand: OE Match
• Component: coolant supply hose.
• Supplied part reference: 99710674006
• Additional catalogue references: 99710674004 and 99710674005.

Symptoms of Fault

• Wetness or seepage at either connection.
• A falling coolant level or dashboard level alert.
• A sweet smell or deposits near the hose.
• Temperature readings higher than usual.
• Bulging, splits, hardened areas or unusually soft sections.
• Gurgling associated with low coolant or trapped air.

Why Replacement Matters

Repeated heating and cooling, pressure, vibration and contamination can weaken a hose over time. Renew it when inspection confirms deterioration or identifies it as the leak source. A small seep can develop into substantial fluid loss, so investigate recurring level drops rather than relying on repeated top-ups.

During related cooling repairs, inspect adjoining pipes, fittings, retainers and seals. Check the hose routing and connection security, then refill and bleed according to the vehicle-specific procedure.

FAQs

How should a suspected leak be confirmed?
A cooling-system pressure test and inspection of the hose connections can help distinguish hose leakage from nearby component faults.

Can coolant collect without leaving a puddle?
Yes. Fluid may collect on an undertray or evaporate, leaving deposits rather than obvious drips.

Related reference numbers
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99710674006

The product you are viewing cross references to these numbers

Water pipe. RETURN LINE.

Fits:
Porsche 987 Boxster MKI 2005-08
Porsche 987 Boxster MKII 2009-12
Porsche 987C Cayman MKI 2006-08
Porsche 987C Cayman MKII 2009-12

Porsche 997 Carrera 3.6L / 3.8L MKI 2005-08 COUPE / CABRIO
Porsche 997 Carrera 3.6L / 3.8L MKII 2009-12 COUPE / CABRIO / TARGA
Porsche 997 TURBO / TURBO S / GT2 / GT2 RS 2007>>
Porsche 997 GT3 2007-11

Click 'Zoom in' for large parts diagram.
Diagram ref no 2

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

99710672003

The product you are viewing cross references to these numbers

Water pipe. RETURN LINE.

Fits:
Porsche 987 Boxster MKI 2005-08
Porsche 987 Boxster MKII 2009-12
Porsche 987C Cayman MKI 2006-08
Porsche 987C Cayman MKII 2009-12

Porsche 997 Carrera 3.6L / 3.8L MKI 2005-08 COUPE / CABRIO
Porsche 997 Carrera 3.6L / 3.8L MKII 2009-12 COUPE / CABRIO / TARGA
Porsche 997 TURBO / TURBO S / GT2 / GT2 RS 2007>>
Porsche 997 GT3 2007-11

Click 'Zoom in' for large parts diagram.
Diagram ref no 2

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

99710672003

The product you are viewing cross references to these numbers