Coolant Hoses - Engine Bay


Fits:
Porsche 996 Carrera 1998-05
Porsche 996 Turbo 2001-05
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Diagram ref no 5
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99610672305
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

Hose for long supply tube from engine to short tube going to radiator breather.

Fits:
Porsche 996 C4 / C4S 1998-05
All-wheel drive (option code: 339)
This product supersedes Porsche's old part numbers:
- 99610672403
- 99610672405
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Diagram ref no 6
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99610672406
The product you are viewing cross references to these numbers
- Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005
Hose for long supply tube from engine to short tube going to radiator breather.

Fits:
Porsche 996 C4 / C4S 1998-05
All-wheel drive (option code: 339)
This product supersedes Porsche's old part numbers:
- 99610672403
- 99610672405
Click 'Zoom in' for large parts diagram.
Diagram ref no 6
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610672406
The product you are viewing cross references to these numbers
- 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 C2 / C4 / C4S- 2002 to 2005
Porsche 997.1 C2 / C4 - 2005 to 2008
Porsche 997.1 C2S / C4S - 2005 to 2008
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Diagram ref no 23
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Related, superseded, cross reference or alternative numbers for comparison.
99710683103
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- 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 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

Fits:
Porsche 996 C2 / C4 / C4S- 2002 to 2005
Porsche 997.1 C2 / C4 - 2005 to 2008
Porsche 997.1 C2S / C4S - 2005 to 2008
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Diagram ref no 23
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99710683103
The product you are viewing cross references to these numbers
- 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 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

Fits:
Porsche 996 C2 / C4 3.4L
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Diagram ref no 23
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99610650156
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


Fits:
Porsche 996 C2 2002>>
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Diagram ref no 1
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99610684007
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- Porsche 996 C2 3.6L 09/01-2005


Fits:
Porsche 996 C2 / C4 3.4L
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Diagram ref no 23
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99610650156
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


Fits:
Porsche 996 C2/ C4 3.6L
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Diagram ref no 23
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Related, superseded, cross reference or alternative numbers for comparison.
99610683203
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- Porsche 996 C2 3.6L 09/01-2005
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005

Fits
Porsche 996 Turbo
Porsche 996 GT2
These replace the glued in water pipe unions on
the water pump housing, power steering pump carrier and coolant connection housing. 3 x unions on the water pump housing 2 x unions on the coolant connection housing 1 x union on the power steering pump carrier
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.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
BBICOOLKIT996
The product you are viewing cross references to these numbers
- 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 996 C2 3.4L 1998-01 MANUAL
This product supersedes Porsche's old part numbers:
- 99610664156
- 99610664158
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Diagram ref no 3
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99610664162
The product you are viewing cross references to these numbers
- Porsche 996 C2 3.4L 1997-08/01

Fits:
Porsche 996 C2 3.4L 1998-01 MANUAL
This product supersedes Porsche's old part numbers:
- 99610664156
- 99610664158
Click 'Zoom in' for large parts diagram.
Diagram ref no 3
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99610664162
The product you are viewing cross references to these numbers
- Porsche 996 C2 3.4L 1997-08/01


Fits:
Porsche 996 C4 3.4L 1998-01 MANUAL
This product supersedes Porsche's old part numbers:
- 99610674104
- 99610674106
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Diagram ref no 3
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99610674110
The product you are viewing cross references to these numbers
- Porsche 996 C4 3.4L 1997-08/01

Fits:
Porsche 996 C4 3.4L 1998-01 MANUAL
This product supersedes Porsche's old part numbers:
- 99610674104
- 99610674106
Click 'Zoom in' for large parts diagram.
Diagram ref no 3
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610674110
The product you are viewing cross references to these numbers
- Porsche 996 C4 3.4L 1997-08/01

Fits:
Porsche 996 C4 3.4L 1998-01 TIPTRONIC
This product supersedes Porsche's old part numbers:
- 99610674107
Diagram ref no 3
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99610674111
The product you are viewing cross references to these numbers
- Porsche 996 C4 3.4L 1997-08/01


Fits:
Porsche 996 C2 2002-05
6-Speed Manual Transmission
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Diagram ref no 3
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99610684110
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- Porsche 996 C2 3.6L 09/01-2005
Coolant Hoses – Engine Bay | Reliable Cooling for Peak Porsche Performance
Coolant hoses in the engine bay are critical components that circulate coolant between the radiator, water pump, and engine block — maintaining consistent operating temperatures and preventing overheating. These hoses carry coolant through high-pressure, high-temperature zones within the engine bay, ensuring your Porsche performs at its best, even under demanding conditions.
At Design911, we stock a wide range of genuine and manufacturer-quality engine bay coolant hoses for Porsche models including 911, Boxster, Cayman. Each hose is designed to fit perfectly, resist extreme temperatures, and deliver long-lasting performance — matching the quality, precision and reliability.
What Do Engine Bay Coolant Hoses Do?
Coolant hoses form part of your Porsche’s closed-loop
cooling system. Their job is to:
- Circulate
coolant between the engine, radiator, and water pump.
- Maintain
engine temperature for optimal performance and emissions.
- Support
consistent coolant pressure during operation.
- Prevent engine overheating and protect internal components from heat damage.
In high-performance engines, such as those found in Porsche vehicles, properly functioning hoses are essential for ensuring precise temperature control and long-term mechanical integrity.
Why Do Engine Bay Coolant Hoses Fail?
Over time, coolant hoses endure constant exposure to heat,
vibration, and pressure, which can cause wear and eventual failure. Common
causes include:
- Rubber
deterioration from heat cycling and coolant chemicals.
- Cracking
or hardening due to age and environmental factors.
- Swelling
or soft spots from internal coolant corrosion.
- Leaks
at connections caused by weakened hose ends or clamps.
- Abrasion or rubbing against other engine components.
Symptoms of failure include coolant leaks, overheating, fluctuating temperature readings, or a noticeable smell of coolant in the engine bay.
Why Replace Faulty Coolant Hoses?
A damaged or leaking hose can cause rapid coolant loss and severe engine overheating. Replacing worn hoses ensures your Porsche’s cooling system functions reliably and efficiently.
Benefits of replacement include:
- Restored coolant circulation and temperature control.
- Prevention of leaks, overheating, and potential engine damage.
- Improved reliability and performance under all driving conditions.
- Manufacturer-quality construction and perfect fitment.
All hoses in this range are built using reinforced, high-grade rubber compounds designed to withstand extreme heat, pressure, and vibration — ensuring lasting durability and peace of mind.