Coolant Hoses - Engine Bay

BBi Autosport billet aluminium coolant pipe repair kit



Fits
Porsche 997 Gen 1 Turbo
Porsche 997 Gen 1 GT2

Coolant pipe failure is an inevitable problem with the Porsche GT1-block equipped models (GT3, GT2, Turbo).
Bonded together by adhesives, the factory pipes will eventually leak or abruptly fail. As the best preventative fix and solution for this problem, BBi Autosport offers replacement billet aluminum coolant pipes to be permanently welded in place.
Compared to the factory fittings, these replacement billet fittings offers superior metallurgy to allow stronger, higher quality welds.

Extensive surface preparation and welding skills are required to properly weld the fittings.

The engine requires removing and the necessary components disassembled and thoroughly cleaned, ideally in a ultrasonic cleaner.
Afterwards, the pipes need to be meticulously welded into place and pressure tested for leaks prior to reinstalling the engine.

Coolant return pipe.



Fits:
Porsche 997.1 Turbo 3.6L / GT2 2007-09
Porsche 997.2 GT2 RS 3.6L 2010-13

Click 'Zoom in' for large parts diagram.
Diagram ref no 4

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99710625474

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Coolant supply line for the turbocharger. 

Fits:
Porsche 997-1 Turbo / GT2 2007-09 
Porsche 997-2 GT2 RS 2011-13

Diagram reference(s):

No. 11 - Cylinders 1-3
No. 12 - Cylinders 4-6

NOTE: Our product image shows 99710607379, which is for cylinders 1-3.

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99710607

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Heater hose - Engine to return line.
Genuine Porsche Original Equipment (OE) heater coolant return hose that connects between the engine cooling circuit and the heater return line, ensuring proper coolant flow through the heater core and back to the engine cooling system.

Fits:
Porsche 996 Carrera 2002 - 2005 Tiptronic Gearbox only
Porsche 997.1 3.6L / 3.8L 2004 - 2008
Porsche 997.1 Turbo / GT2 2007 - 2009
Porsche 997.2 Turbo / GT2 RS 2010 - 2013
Porsche 997 GT3 3.8 / 4.0 2009 - 2011

Diagram ref no 42

This hose ensures an unobstructed and secure channel for coolant returning from the vehicle’s heater core to the engine cooling loop, playing a vital role in passenger cabin heating and overall engine thermal regulation. Its precise fit and correct routing are essential to avoid bypassing or pinching, which could otherwise lead to heater inefficiency or premature failure.

Installed between the heater core outlet and the engine’s return fitting, this hose:
• Transports heated coolant from the heater core back to the engine cooling system
• Maintains correct flow and pressure balance within the cooling circuit
• Operates under high temperatures and multiple thermal cycles
•  Interfaces with factory-specified clamps and hose connections
Because it is made to OE specification, the hose ensures proper sealing and routing that matches the original Porsche design.

A cooling system hose that has become brittle, cracked, swollen, or porous can leak or restrict flow, leading to reduced heating performance, coolant loss, and potential engine overheating. Because the heater return hose carries pressurised coolant across temperature extremes, degradation over time is typical. Replacing it with a Genuine Porsche OE part ensures correct material performance and sealing, helping preserve cooling efficiency and prevent unexpected failures.

When to replace:
•  Visible cracks, swelling, or soft spots
•  Coolant leaks around the hose ends
•  Heater blowing cold air, indicating poor coolant flow
•  Cooling system overhaul or heater core service
•  Preventive maintenance on high-mile vehicles

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99610622275

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Heater hose - Engine to return line.
OE Match heater coolant return hose is a direct-fit replacement designed to replicate the original Porsche hose used in the heater return circuit on Porsche 911 996 and 997 models. It carries coolant from the heater core back into the engine cooling system, supporting both cabin heating and overall thermal regulation.

Fits:
Porsche 996 Carrera 2002 - 2005 Tiptronic Gearbox only
Porsche 997.1 3.6L / 3.8L 2004 - 2008
Porsche 997.1 Turbo / GT2 2007 - 2009
Porsche 997.2 Turbo / GT2 RS 2010 - 2013
Porsche 997 GT3 3.8 / 4.0 2009 - 2011

Diagram ref no 42

The hose installs directly using original mounting points and standard Porsche hose clamps, making it suitable for both routine maintenance and larger cooling system overhauls.

The heater coolant return hose channels warmed coolant from the heater core back to the engine’s cooling circuit, completing the heater loop. This allows the cooling system to maintain balanced flow and ensures consistent interior heating performance.

Installed between the heater core outlet and the engine return line, this hose:
•  Maintains correct coolant flow and pressure in the heater circuit
•  Supports reliable cabin heating
•  Resists collapse, swelling, and heat degradation
•  Integrates with factory hose routing and connections
 Its OE-matched geometry ensures proper clearance and reduces stress on joints and adjacent hoses.

Over time, heater hoses deteriorate due to heat cycling and coolant exposure. A failing return hose can cause coolant leaks, reduced heating efficiency, air ingress into the cooling system, or engine overheating. Replacing worn hoses with an OE Match component restores proper coolant circulation and helps prevent unexpected cooling system failures.

When to replace:
•  Visible cracks, swelling, or soft spots
•  Coolant leaks around the hose ends
•  Heater blowing cold air, indicating poor coolant flow
•  Cooling system overhaul or heater core service
•  Preventive maintenance on high-mile vehicles

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99610622275

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O-ring 39,20 x 3,00 water cooling. 

Fits:
Porsche 996 turbo - 2000 to 2005
Porsche 996 GT3 - 1999 to 2004
Porsche 997.1 turbo - 2007 to 2009
Porsche 997 GT3 - 2007 to 2011
Porsche Carrera GT - 2003 to 2006
Porsche 918 Spyder

Diagram ref no 14

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99970741040

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O-ring 39,20 x 3,00 water cooling
This OE match O-ring is a direct replacement for the original Porsche sealing ring used within the water cooling systems of Porsche 996 Turbo, 996 GT3, 997 Turbo, and 997 GT3 models. Manufactured to OE specifications, it features precise dimensions of 39.20mm x 3.00mm to ensure correct sealing performance and factory-style fitment.
Sold individually

Fits:
Porsche 996 turbo - 2000 to 2005
Porsche 996 GT3 - 1999 to 2004
Porsche 997.1 turbo - 2007 to 2009
Porsche 997 GT3 - 2007 to 2011
Porsche Carrera GT - 2003 to 2006
Porsche 918 Spyder

Diagram ref no 14

Proper sealing within the cooling system is essential for maintaining coolant pressure and preventing leaks that could lead to overheating or engine damage. OE Match construction ensures compatibility with original Porsche cooling system components and reliable sealing performance under demanding operating conditions.

Ideal for preventative maintenance, cooling system servicing, or engine rebuild work, this O-ring helps restore proper sealing integrity and reliable coolant circulation.

The O-ring creates a pressure-tight seal between cooling system components, preventing coolant leaks and maintaining correct cooling system pressure. It helps ensure efficient coolant circulation and reliable engine temperature control.

Function
• Seals coolant system connections and housings
• Prevents coolant leakage under pressure
• Maintains correct cooling system pressure
• Supports reliable engine temperature regulation
• Resists heat, coolant exposure, and pressure cycling

Cooling system O-rings harden and lose elasticity over time due to heat exposure, coolant chemicals, and pressure cycling. A deteriorated seal can cause coolant leaks, pressure loss, overheating, and potential engine damage. Replacing worn O-rings during servicing helps maintain cooling system integrity and prevents costly repairs.

When to replace
•  Coolant leaks around sealed connections
•  During cooling system disassembly or servicing
•  Signs of flattened, cracked, or hardened seals
•  Loss of coolant pressure
•  During engine rebuild or preventative maintenance

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99970741040

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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

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99610680103

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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

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99610680103

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Protective Ring For Engine Coolant Pipe.
Sold Each.
x2 Required Per Car.

Fits:
Porsche 996 Turbo / GT2 2001>>2005
Porsche 996 GT3 1999>>2005
Porsche 997.1 Turbo / GT2 MKI 2007>>2009
Porsche 997.1 GT3 MKI 2007>>2009
Porsche 997.2 Turbo / GT2 RS MKII 2010>>2013
Porsche 997.2 GT3 MKII 2010>>2011

Diagram Ref No 16

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99610621470

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Water coolant hose return. 



Fits:
Porsche 997.1 turbo - 2007 to 2008
Porsche 997.2 GT2 - 2001 to 2012
Porsche 997 GT3 - 2007 to 2012

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Diagram ref no 2 or 45

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99710632872

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Water coolant hose, supply.



Fits:
Porsche 997.1
Porsche 997.2

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Diagram ref no 17

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99710674006

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Water Coolant Pipe, Supply.

Fits:
Porsche 997.1 2005-08
Porsche 997.2 2009-12

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Diagram ref no 1

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99710661032

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Water Hose Supply. 

The Porsche Water Hose Supply 99710650101 is a genuine replacement coolant supply hose designed for selected Porsche 997 performance models.

Fits:

• Porsche 997 MK1 TURBO 2007-09
• Porsche 997 MK1 GT3 / GT3 RS 2007-09
• Porsche 997 MK1 GT2 2007-09
• Porsche 997 MKII GT3 / GT3 RS 2010-11
• Porsche 997 MKII Turbo 2010-13
• Porsche 997 MKII GT2 RS 2011-13  

Diagram Ref No 9

Located on the right-hand side of the engine cooling circuit, the hose carries coolant from the supply pipe towards the engine, helping maintain continuous coolant circulation and stable operating temperatures.

Manufactured to Porsche specifications, this replacement restores the original hose routing, connections and sealing arrangement when the existing hose has become cracked, hardened, swollen or is leaking.

What This Product Does:
The engine cooling system continuously circulates coolant through the engine, radiators and associated pipework to absorb and dissipate heat.

This supply hose forms part of that circulation path and delivers coolant from the supply pipe into the engine cooling circuit.

Its main functions include:

• Carrying coolant towards the engine
• Maintaining continuous coolant circulation
• Helping maintain correct cooling-system pressure
• Supporting stable engine operating temperatures
• Providing a sealed connection between the coolant pipe and engine
• Helping prevent coolant loss
• Maintaining the original factory hose routing
• Supporting effective engine thermal management

The hose itself does not lower coolant temperature, but reliable coolant flow through it is essential for the cooling system to function correctly.

Symptoms Of Wear Or Failure:
Coolant hoses operate under continuous heat and pressure and can deteriorate as they age.

Common symptoms of a worn or failing coolant supply hose include:

• Visible coolant leakage
• Dampness around the hose or fittings
• Dried coolant residue around connection points
• Cracks or splits in the hose
• Rubber becoming hard or brittle
• Swelling or bulging sections
• Hose becoming excessively soft or spongy
• Damaged or loose hose connections
• Low coolant warning
• Repeated need to top up coolant
• Sweet coolant smell around the engine bay
• Engine temperature rising above normal
• Fluctuating coolant temperature
• Steam from the engine compartment in severe cases

Cooling-system leaks can also originate from radiators, expansion tanks, water pumps, pipe connections or other hoses, so the complete circuit should be inspected.

Why Replacement Matters:
The cooling system must remain sealed and properly pressurised to control engine temperature effectively.

If the supply hose begins to leak, coolant can escape and the system may gradually lose both fluid and pressure. As the coolant level falls, the engine becomes less able to transfer and dissipate heat.

A deteriorated hose may also split suddenly under operating pressure, causing rapid coolant loss.

Continued operation with insufficient coolant can lead to:

• Engine overheating
• Cylinder-head damage
• Head-gasket damage
• Damage to seals and cooling-system components
• Reduced engine reliability
• Breakdown caused by sudden coolant loss

Replacing a deteriorated hose helps restore:

• Correct coolant circulation
• Proper cooling-system pressure
• A sealed cooling circuit
• Stable engine temperature
• Reliable long-term cooling-system operation

Replacing a hose at the first sign of leakage, cracking or swelling can help prevent a relatively minor cooling-system fault from becoming a much more expensive engine repair.

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99710650101

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Water Hose.

The Porsche Water Hose 99710635000 is a genuine Porsche replacement coolant hose used within the coolant expansion tank / filling circuit on selected high-performance Porsche 997 models.

Fits:

• Porsche 997 MK1 TURBO 2007-09
• Porsche 997 MK1 GT3 / GT3 RS 2007-09
• Porsche 997 MK1 GT2 2007-09
• Porsche 997 MKII Turbo 2010-13
• Porsche 997 MKII GT2 RS 2011-13  

Diagram Ref No 13

The hose connects into the pressurised engine cooling system and allows coolant to move correctly between the expansion reservoir and the associated cooling circuit.

Because the cooling system operates under pressure and experiences repeated heating and cooling cycles, maintaining this hose in good condition is essential for preventing coolant loss and maintaining stable engine temperatures.

As a Genuine Porsche component, 99710635000 provides the correct factory-style dimensions, routing and connection points for the intended application.

What This Product Does:
The coolant hose forms part of the expansion reservoir and cooling-system plumbing.

Its main functions include:

• Carrying coolant between the expansion reservoir and cooling circuit
• Supporting correct filling and coolant movement
• Maintaining a sealed cooling system
• Helping maintain correct system pressure
• Allowing expansion and contraction of coolant as temperature changes
• Helping maintain the correct coolant level
• Supporting reliable engine temperature control
• Maintaining the original Porsche cooling-system routing

The hose works together with the coolant reservoir, bleed system, water pump, thermostat, radiators and remaining coolant pipework.

Symptoms Of Wear Or Failure:
Coolant hoses deteriorate gradually due to age, heat, pressure and repeated thermal cycling.

Common symptoms include:

• Visible coolant leakage
• Coolant staining around the hose
• Wetness around the expansion tank connection
• Pink, white or crusty dried coolant residue
• Falling coolant level
• Frequent need to top up coolant
• Low coolant warning
• Sweet coolant smell
• Cracked hose surface
• Hardened or brittle rubber
• Swollen or unusually soft sections
• Bulging when the system is pressurised
• Damaged hose ends
• Leakage around clamps
• Steam or coolant vapour after driving
• Fluctuating engine temperature
• Engine overheating in severe cases

Minor leaks may only become visible when the engine is fully warm and the cooling system has reached operating pressure.

Why Replacement Matters:
A leaking hose can gradually reduce the amount of coolant in the system.

If coolant loss continues, the system may no longer be able to control engine temperature effectively.

Continued operation with a damaged hose can result in:

• Coolant loss
• Loss of system pressure
• Air entering the cooling circuit
• Poor coolant circulation
• Localised hot spots
• Overheating
• Coolant warning messages
• Roadside breakdown
• Serious engine damage if overheating continues

Replacing a deteriorated hose helps restore a sealed cooling circuit and reliable coolant circulation.

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99710635000

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