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Porsche > 991 (911) MK2 2016-2019 > 991.2 Turbo S Coupe 3.8L (580 Bhp) 2016-19 > Engine Cooling > Coolant Hoses and Pipes (Rear engine cars) >

Coolant Hoses - Radiator Section

Coolant Hoses - Radiator Section

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DISPLAYING 1 to 7 (of 7 products)
Coolant Hose for Centre Radiator. Porsche 991 turbo - 99110664801
2
Coolant Hose for Centre Radiator. Porsche 991 turbo
Special Order item
99110664801
Product Information
Product Information

Centre Radiator Coolant Hose

These coolant hoses are designed for the centre radiator on the Porsche 991 Turbo, forming an important part of the high-performance cooling system used in Porsche’s twin-turbocharged flat-six engines.

Fits:

  • Porsche 991.1 Turbo 3.8L (520 Bhp) 2014-16
  • Porsche 991.1 Turbo S 3.8L (560 Bhp) 2014-16
  • Porsche 991.2 Turbo Coupe 3.8L (540 Bhp) 2016-19
  • Porsche 991.2 Turbo S Coupe 3.8L (580 Bhp) 2016-19
  • Porsche 991.2 Turbo Cabriolet 3.8L (540 Bhp) 2016-19
  • Porsche 991.2 Turbo S Cabriolet 3.8L (580 Bhp) 2016-19

Diagram Ref No 7 

The hoses ensure coolant flows correctly between the engine and the centre radiator, allowing excess heat to be dissipated efficiently. Maintaining proper coolant circulation is essential for protecting the engine from overheating and ensuring reliable performance under demanding driving conditions.

What These Coolant Hoses Do

The Porsche 991 Turbo cooling system uses multiple radiators positioned at the front of the vehicle to manage the large amount of heat generated by the turbocharged engine.

The centre radiator hoses perform several key functions:

• Carry coolant to and from the centre radiator
• Support proper coolant circulation through the cooling system
• Help regulate engine temperature under high load conditions
• Maintain efficient heat dissipation during spirited driving

Without these hoses functioning correctly, coolant flow may be restricted, reducing cooling efficiency and increasing the risk of overheating.

Why Coolant Hoses Fail

Cooling system hoses are constantly exposed to high temperatures, pressure and vibration. Over time these stresses can lead to deterioration.

Common causes of coolant hose failure include:

Heat ageing
 Continuous heat cycles cause rubber hoses to harden and lose flexibility.

Pressure fatigue
 Cooling systems operate under pressure, which can cause weakened hoses to swell or crack.

Chemical degradation
 Coolant additives and contaminants can break down rubber compounds over time.

Mechanical wear
 Engine movement and vibration may cause abrasion or stress on hose connections.

Symptoms of Worn or Failing Coolant Hoses

• Coolant leaks from the front of the vehicle
• Low coolant warning messages
• Sweet coolant smell near the front bumper area
• Rising engine temperatures
• Visible cracking, swelling or deterioration in the hose material

Replacing worn hoses helps prevent unexpected coolant loss and ensures the cooling system operates correctly.

Why You May Need to Replace These Hoses

Protect Engine Performance
 The Porsche 991 Turbo engine generates significant heat, making reliable cooling system components essential.

Prevent Coolant Leaks
 Replacing ageing hoses helps maintain system pressure and prevent leaks.

Maintain Cooling Efficiency
 Healthy hoses ensure proper coolant flow through the centre radiator and the rest of the cooling system.

Prevent Costly Engine Damage
 Overheating caused by coolant loss can lead to severe engine damage if not addressed quickly.



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

99110664801
99110664801

The product you are viewing cross references to these numbers
Coolant Hose for Centre Radiator. Porsche 991 turbo - 99110664901
2
Coolant Hose for Centre Radiator. Porsche 991 turbo
Special Order item
99110664901
Product Information
Product Information

Centre Radiator Coolant Hose

These coolant hoses are designed for the centre radiator on the Porsche 991 Turbo, forming an important part of the high-performance cooling system used in Porsche’s twin-turbocharged flat-six engines.

Fits:

  • Porsche 991.1 Turbo 3.8L (520 Bhp) 2014-16
  • Porsche 991.1 Turbo S 3.8L (560 Bhp) 2014-16
  • Porsche 991.2 Turbo Coupe 3.8L (540 Bhp) 2016-19
  • Porsche 991.2 Turbo S Coupe 3.8L (580 Bhp) 2016-19
  • Porsche 991.2 Turbo Cabriolet 3.8L (540 Bhp) 2016-19
  • Porsche 991.2 Turbo S Cabriolet 3.8L (580 Bhp) 2016-19

Diagram Ref No 7

The hoses ensure coolant flows correctly between the engine and the centre radiator, allowing excess heat to be dissipated efficiently. Maintaining proper coolant circulation is essential for protecting the engine from overheating and ensuring reliable performance under demanding driving conditions.

What These Coolant Hoses Do

The Porsche 991 Turbo cooling system uses multiple radiators positioned at the front of the vehicle to manage the large amount of heat generated by the turbocharged engine.

The centre radiator hoses perform several key functions:

• Carry coolant to and from the centre radiator
• Support proper coolant circulation through the cooling system
• Help regulate engine temperature under high load conditions
• Maintain efficient heat dissipation during spirited driving

Without these hoses functioning correctly, coolant flow may be restricted, reducing cooling efficiency and increasing the risk of overheating.

Why Coolant Hoses Fail

Cooling system hoses are constantly exposed to high temperatures, pressure and vibration. Over time these stresses can lead to deterioration.

Common causes of coolant hose failure include:

Heat ageing
 Continuous heat cycles cause rubber hoses to harden and lose flexibility.

Pressure fatigue
 Cooling systems operate under pressure, which can cause weakened hoses to swell or crack.

Chemical degradation
 Coolant additives and contaminants can break down rubber compounds over time.

Mechanical wear
 Engine movement and vibration may cause abrasion or stress on hose connections.

Symptoms of Worn or Failing Coolant Hoses

• Coolant leaks from the front of the vehicle
• Low coolant warning messages
• Sweet coolant smell near the front bumper area
• Rising engine temperatures
• Visible cracking, swelling or deterioration in the hose material

Replacing worn hoses helps prevent unexpected coolant loss and ensures the cooling system operates correctly.

Why You May Need to Replace These Hoses

Protect Engine Performance
 The Porsche 991 Turbo engine generates significant heat, making reliable cooling system components essential.

Prevent Coolant Leaks
 Replacing ageing hoses helps maintain system pressure and prevent leaks.

Maintain Cooling Efficiency
 Healthy hoses ensure proper coolant flow through the centre radiator and the rest of the cooling system.

Prevent Costly Engine Damage
 Overheating caused by coolant loss can lead to severe engine damage if not addressed quickly.



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

99110664901
99110664901

The product you are viewing cross references to these numbers
Coolant Hose Lower. Porsche 991 turbo - 99110693501, 99110663601
3
Coolant Hose Lower. Porsche 991 turbo
Special Order item
99110663
Product Information
Product Information

Lower Feed and Return Coolant Hoses

These lower coolant hoses are designed for the side radiators on the Porsche 991 Turbo and form an essential part of the vehicle’s high-performance cooling system. The hoses carry coolant between the engine cooling circuit and the left and right radiators, ensuring that excess heat is efficiently dissipated during operation.

Fits:

  • Porsche 991.1 Turbo 3.8L (520 Bhp) 2014-16
  • Porsche 991.1 Turbo S 3.8L (560 Bhp) 2014-16
  • Porsche 991.2 Turbo Coupe 3.8L (540 Bhp) 2016-19
  • Porsche 991.2 Turbo S Coupe 3.8L (580 Bhp) 2016-19
  • Porsche 991.2 Turbo Cabriolet 3.8L (540 Bhp) 2016-19
  • Porsche 991.2 Turbo S Cabriolet 3.8L (580 Bhp) 2016-19

Diagram Ref No 9
 
Turbocharged Porsche engines generate significant heat under acceleration and high load conditions. Maintaining proper coolant circulation through all radiators is critical for protecting the engine and maintaining consistent performance.

What These Coolant Hoses Do

The Porsche 991 Turbo uses multiple front-mounted radiators to manage engine temperatures. The side radiators assist in removing heat from the coolant as it flows through the cooling system.

The lower feed and return hoses help:

• Deliver coolant from the engine to the side radiators
• Return cooled coolant back into the engine’s cooling circuit
• Maintain proper coolant circulation throughout the system
• Support stable operating temperatures during high performance driving

Without reliable coolant hoses, the system cannot properly transport coolant, reducing the efficiency of the radiators.

Why Coolant Hoses Fail

Cooling system hoses operate in harsh conditions and are exposed to continuous heat, pressure and vibration. Over time the materials degrade and can eventually fail.

Common causes include:

Heat degradation
 Constant temperature cycling can cause the rubber to harden or crack.

Pressure fatigue
 Cooling systems run under pressure which can weaken ageing hoses.

Coolant contamination
 Old coolant or debris can damage the hose material internally.

Mechanical wear
 Movement and vibration from the engine and chassis can stress the hose over time.

Symptoms of a Failing Coolant Hose

• Coolant leaks from the front of the vehicle
• Low coolant warning lights on the dashboard
• Sweet coolant smell from the front bumper area
• Visible swelling, cracking or deterioration in the hose
• Engine temperature fluctuations or overheating warnings

Replacing worn coolant hoses early prevents sudden coolant loss and protects the engine from overheating.

Why You May Need to Replace These Hoses

Maintain Cooling System Performance
 Efficient coolant circulation ensures the radiators can properly remove heat from the engine.

Prevent Coolant Leaks
 New hoses restore system integrity and maintain correct coolant pressure.

Protect the Turbocharged Engine
 The Porsche 991 Turbo engine produces high heat levels, making cooling system reliability essential.

Prevent Costly Engine Damage
 Overheating caused by coolant leaks can lead to serious mechanical damage if not addressed.



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

99110663
99110693501
99110663601

The product you are viewing cross references to these numbers
Coolant Overflow/Breather Pipe for Porsche 991 Turbo / S / 991-1 GT3 / RS - 99110686501, 99110686601
3
Coolant Overflow/Breather Pipe for Porsche 991 Turbo / S / 991-1 GT3 / RS
Special Order item
99110686
Product Information
Product Information
Engine coolant overflow / breather line.

Fits:
Porsche 991 Turbo / S 2014-20 - Excludes GT2 RS models
Porsche 991-1 GT3 / RS 2014-17

Diagram ref. 20.

NOTE: Our product image shows 99110686501, which is for the left side. 

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

99110686
99110686501
99110686601

The product you are viewing cross references to these numbers
O-Ring for Cooling System (46.7x3.53) - Several Applications. Porsche 987 / 981 / 718 / 996 / 997 / 991 - 99610680103
9
O-Ring for Cooling System (46.7x3.53) - Several Applications. Porsche 987 / 981 / 718 / 996 / 997 / 991
Special Order item
99610680103
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

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

99610680103
99610680103

The product you are viewing cross references to these numbers
O-Ring for Cooling System (46.7x3.53) - Several Applications. Porsche 987 / 981 / 718 / 996 / 997 / 991 - 99610680103 - ORS161125
9
O-Ring for Cooling System (46.7x3.53) - Several Applications. Porsche 987 / 981 / 718 / 996 / 997 / 991
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

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

99610680103
99610680103

The product you are viewing cross references to these numbers
Upper Radiator Hose. Porsche 991-1 GT3 / RS 2014-17 / 991 Turbo 2014-20 - 99110663101, 99110663201
4
Upper Radiator Hose. Porsche 991-1 GT3 / RS 2014-17 / 991 Turbo 2014-20
Special Order item
99110663
Product Information
Product Information
Upper radiator hose. 

Fits:
Porsche 991 Turbo / S 2014-20 - Excludes GT2 RS
Porsche 991-1 GT3 / RS 2014-17

Diagram ref. 10.

NOTE: Our product image shows 99110663201, which is for the right-side radiator. 

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

99110663
99110663101
99110663201

The product you are viewing cross references to these numbers
DISPLAYING 1 to 7 (of 7 products)
Also found on these pages
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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