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DISPLAYING 1 to 13 (of 13 products)
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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
99610680103

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99610680103/1
Product Information
Product Information
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
99610680103

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Special Order item
99610613
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Product Information
Radiator breather hose.

porsche

Fits:
Porsche 986 Boxster 1997-04
Porsche 996 C2 / C4 1998-04
Porsche 996 GT3 1999-05
 
Click 'Zoom in' for large parts diagram.
Diagram ref no 11

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99610613
99610613753
99610613853

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99610662558/1
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Water radiator bottom hose, LEFT.
This hose serves as the lower radiator return hose (left side) in the engine cooling system of the Porsche 996 Carrera / Carrera 4 and 986 Boxster S 3.2L.  It replaces older hose numbers such as 99610662554 and 99610662557, offering a faithful reproduction of the original hose in terms of shape, diameter, and fitment.

Fits:
Porsche 996 C2 / C4 1998 - 2005
Porsche 986 Boxster S 3.2L 1997 - 2004

Diagram Ref No 9.

The radiator coolant hose circulates engine coolant between the radiator and engine blocks or cooling passages. As a key part of the cooling system, it helps transfer heated fluid away from the engine and into the radiator to be cooled, then back into the engine - maintaining stable operating temperatures and preventing overheating under normal driving conditions. A robust and properly functioning coolant hose ensures efficient heat dissipation and preserves engine performance.

Function:
Transfers coolant between the radiator and engine cooling system
 Helps maintain optimal engine temperatures
 Reduces the risk of overheating and coolant leaks
 Made from heat- and fluid-resistant materials to endure typical engine bay conditions

Radiator hoses are constantly exposed to engine heat, pressure cycles, and coolant chemicals. Over time, hoses can dry out, crack, soften, or swell, leading to leaks or cooling system failure. A compromised hose can quickly result in engine overheating, potential head gasket damage, and costly repairs. Replacing a worn or aged hose restores secure coolant flow, enhances system integrity, and helps maintain original-style engine temperature management.

Replace this radiator hose if:
 The hose shows cracks, swelling, or brittleness
 Coolant is visible leaking around hose connections or surface
 The hose feels soft or mushy under pressure
 You notice engine overheating or rapid temperature fluctuations
 Routine cooling system maintenance or belt/thermostat replacement

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

99610662558
99610662558
99610662557
99610662554

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Special Order item
99610662558
Product Information
Product Information
Water radiator bottom hose return, LEFT.

Fits:
Porsche 996 C2 / C4 1998 - 2005
Porsche 986 Boxster S 3.2L 1997 - 2004

This product supersedes Porsche's old part numbers: 99610662554, 99610662557

Diagram ref no 9.

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99610662558
99610662558
99610662557
99610662554

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99610666656
Product Information
Product Information
Water radiator bottom hose return RIGHT. 

porsche

Fits:
Porsche 996 C2 / C4 1998-05 TIPTRONIC
Porsche 996 C4S 1998-05 TIPTRONIC
Porsche 996 GT3 1998-05 
Porsche 986 Boxster S 3.2L 1997-04

This product supersedes Porsche's old part numbers:
- 99610666651
- 99610666652
- 99610666655

Click 'Zoom in' for large parts diagram.
Diagram Ref No 9.

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99610666656
99610666656
99610666651
99610666652
99610666655

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99610666656/1
Product Information
Product Information
Water Radiator Bottom Hose Return RIGHT.

oematch

Fits:
Porsche 996 C2 / C4 1998-05 TIPTRONIC
Porsche 996 C4S 1998-05 TIPTRONIC
Porsche 996 GT3 1998-05 
Porsche 986 Boxster S 3.2L 1997-04

This product supersedes Porsche's old part numbers:
- 99610666651
- 99610666652
- 99610666655

Click 'Zoom in' for large parts diagram.
Diagram Ref No 9.

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99610666656
99610666656
99610666655
99610666652
99610666651

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99610662158/1
Product Information
Product Information
Water radiator top  hose intake LEFT.

oematch

Fits:
Porsche 996 C2 / C4 1998-05 MANUAL (NOT C4S)

This product supersedes Porsche's old part numbers:
- 99610662157

Click 'Zoom in' for large parts diagram.
Diagram ref no 8.

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99610662158
99610662158
99610662157

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Special Order item
99610666558
Product Information
Product Information
Water Radiator Top Hose Intake Top LEFT.

porsche

Fits:
Porsche 996 C2 / C4 1998-05 TIPTRONIC
Porsche 986 Boxster 2.5L / 2.7L 1997-04 TIPTRONIC
Porsche 986 Boxster S 3.2L

This product supersedes Porsche's old part numbers:
- 99610666555
- 99610666557

Click picture for large parts diagram.
Diagram Ref No 8.

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99610666558
99610666557
99610666558
99610666555

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99610666558/1
Product Information
Product Information
Water radiator top hose, Intake (Upper Left).
OE Match upper-left radiator coolant hose (intake/top hose) designed to replicate the factory hose routing and connections on Tiptronic-equipped 996 and 986 models.

Fits:
Porsche 996 C2 / C4 1998 - 2005 TIPTRONIC
Porsche 986 Boxster 2.5L / 2.7L 1997 - 2004 TIPTRONIC
Porsche 986 Boxster S 3.2L 2000 – 2004

This product supersedes Porsche's old part numbers:
- 99610666555
- 99610666557

Diagram Ref No 8.

This hose transports coolant through the upper (intake) side of the left radiator circuit, supporting efficient heat rejection and stable engine operating temperature.

Function:  This hose links the radiator coolant plumbing on the upper-left side and is shaped to maintain correct flow while clearing bodywork, brackets, and neighbouring hoses. Correct fitment is important to prevent restriction, rubbing, and leak paths at the hose ends as the system expands and contracts with temperature.

Cooling hoses are wear items. A weakened upper hose can split or leak under pressure, leading to coolant loss and overheating risk. Replacing with an OE Match hose restores secure sealing and correct routing, helping protect the engine and keep the cooling system operating as intended.

When to replace:
  Visible coolant seepage at hose ends or along the hose body
  Hose feels overly soft, swollen, brittle, or cracked
  Coolant smell/steam from the front of the car
  Cooling system refresh (radiators/thermostat/water pump service)
  Preventatively on higher-mileage 996/986 models

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

99610666558
99610666557
99610666558
99610666555

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Best Price
99610662255/1
Product Information
Product Information
Water radiator top hose intake, RIGHT.

oematch

Fits:
Porsche 996 C2 / C4 1998-05
Porsche 996 C4S 1998-05
Porsche 986 Boxster S 3.2L 1997-04

This product supersedes Porsche's old part numbers:
- 99610662252
- 99610662254

Click 'Zoom in' for large parts diagram.
Diagram Ref No 8.

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

99610662255
99610662255
99610662252
99610662254

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Special Order item
99610662158
Product Information
Product Information
Water radiator top hose LEFT.

porsche

Fits:
Porsche 996 C2 / C4 1998-05 MANUAL (NOT C4S)

This product supersedes Porsche's old part numbers:
- 99610662157

Click 'Zoom in' for large parts diagram.
Diagram ref no 8.

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99610662158
99610662158
99610662157

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Special Order item
99610662255
Product Information
Product Information
Water radiator top hose RIGHT.

porsche

Fits:
Porsche 996 C2 / C4 1998-05
Porsche 996 C4S 1998-05
Porsche 986 Boxster S 3.2L 1997-04

This product supersedes Porsche's old part numbers:
- 99610662252
- 99610662254

Click pictrue for large parts diagram.
Diagram Ref No 8.

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99610662255
99610662255
99610662252
99610662254

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DISPLAYING 1 to 13 (of 13 products)
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About Coolant Hoses - Radiator Section

Radiator Section Coolant Hoses – Mid & Rear-Engine Porsche Models

Radiator section coolant hoses are essential for managing engine temperature in mid and rear-engine Porsche models. These hoses circulate coolant between the engine and the radiator, ensuring consistent temperature control and preventing overheating under high-performance conditions.

At Design911, we stock a full range of genuine and manufacturer-quality radiator section coolant hoses specifically designed for mid- and rear-engine Porsche models such as the 911, Boxster, and Cayman. Each hose is built to factory specifications for perfect fitment, superior pressure tolerance, and reliable cooling system performance — ensuring your Porsche operates safely and efficiently on road or track.

What Do Radiator Section Coolant Hoses Do?

In Porsche’s mid- and rear-engine designs, coolant must travel a greater distance between the engine (located at the rear or middle) and the radiator (at the front). The radiator section hoses form part of this vital network, helping to:

  • Transport coolant efficiently from the engine to the front radiator.
  • Maintain optimal engine operating temperature for performance and longevity.
  • Regulate coolant flow through the entire system under varying loads.
  • Ensure consistent pressure and leak-free circulation.

These hoses are engineered to handle high thermal and mechanical stress, ensuring reliability even in extreme driving conditions.

Why Do Radiator Coolant Hoses Fail?

Due to their exposure to heat, pressure, and constant coolant flow, radiator section hoses can wear out over time. Common causes of failure include:

  • Material fatigue from heat cycles and pressure changes.
  • Cracks or splits in aging rubber or plastic connectors.
  • Corrosion or leaks around hose clamps and fittings.
  • Swelling or softening from prolonged coolant exposure.
  • Abrasion damage from rubbing against engine or chassis parts.

Symptoms of a failing coolant hose may include coolant leaks under the car, overheating, fluctuating temperature readings, or a low coolant warning light.

Why Replace Faulty Radiator Section Hoses?

A worn or leaking hose can cause coolant loss, overheating, and potential engine damage. Replacing aging hoses is an essential part of preventative maintenance — especially in mid- and rear-engine Porsche models, where efficient cooling is critical.

Benefits of replacement include:

  • Restored, leak-free coolant circulation.
  • Improved temperature control and system pressure.
  • Prevention of costly overheating and engine damage.
  • Manufacturer-quality materials for long-term reliability.

All replacement hoses in this range are constructed using reinforced, high-performance rubber compounds and precision-moulded fittings, ensuring durability, flexibility, and perfect compatibility with Porsche cooling systems.

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