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- Porsche 991.2 Speedster 4.0L (510Bhp) 2019
- Porsche 991.2 GT3 4.0L (500 Bhp) / GT3 RS 4.0L (520 Bhp) 2017-19
Centre Radiator Coolant Hoses
These coolant hoses are designed for the centre radiator on
the Porsche 991.2 GT3, GT3 RS and 991 Speedster. They form part of the
high-performance cooling system used in Porsche’s naturally aspirated GT
engines, ensuring coolant flows efficiently between the engine and the centre
radiator.
Fits:
- Porsche 991.2 Speedster 4.0L (510Bhp) 2019
- Porsche 991.2 GT3 4.0L (500 Bhp) / GT3 RS 4.0L (520 Bhp) 2017-19
Diagram Ref No 6 and 7
High-revving GT models generate substantial heat, particularly during spirited driving and track use. Proper coolant circulation through the centre radiator helps maintain stable engine temperatures and supports consistent performance under demanding conditions.
What These Coolant Hoses Do
The Porsche 991.2 GT3 cooling system uses multiple radiators mounted at the front of the vehicle to manage engine temperatures. The centre radiator increases the system’s cooling capacity and helps remove excess heat from the coolant.
The hoses perform several important functions:
• Carry coolant to and from the centre radiator
• Maintain proper coolant circulation through the cooling system
• Help regulate engine temperature during high performance driving
• Support efficient heat transfer through the radiator core
Without properly functioning hoses, coolant flow may be restricted, reducing the effectiveness of the cooling system.
Why Coolant Hoses Fail
Cooling hoses operate under extreme conditions and are exposed to heat, pressure and vibration throughout their service life.
Common causes of failure include:
Heat ageing
Continuous temperature cycles can cause rubber hoses to harden, crack or lose
flexibility.
Pressure fatigue
Cooling systems operate under pressure, which can weaken hoses over time.
Chemical degradation
Coolant additives and contaminants can gradually break down rubber compounds.
Mechanical wear
Engine movement and vibration may cause stress or abrasion on hose connections.
Symptoms of Failing Coolant Hoses
• Coolant leaks near the front of the vehicle
• Low coolant level warning messages
• Sweet coolant smell around the front bumper area
• Visible cracking or swelling of the hose
• Engine temperature fluctuations during driving
Replacing worn hoses helps maintain proper coolant flow and prevents sudden coolant loss.
Why You May Need to Replace These Hoses
Maintain Cooling System Efficiency
Healthy hoses ensure coolant can circulate freely through the centre radiator
and engine.
Prevent Coolant Leaks
Replacing ageing hoses helps maintain the cooling system’s pressure and
prevents leaks.
Protect the High-Performance GT Engine
The GT3 and GT3 RS engines operate at high temperatures and require a fully
functional cooling system.
Avoid Costly Engine Damage
Loss of coolant can lead to overheating and significant mechanical damage if
not addressed quickly.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99110664
The product you are viewing cross references to these numbers
- 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 GT3 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 GT3 2010-11
- 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
Fits:
Porsche 987 Boxster / S MKI & MKII 2005>>
Porsche 987C Cayman / S MKI & MKII 2006>>
Porsche 997 GT3 2007-2010
Porsche 997 Carrera 2/2S MKI & MKII 2005>> CABRIO/COUPE
This product supersedes Porsche's old part numbers:
- 99710662603
- 99710662604
Click "Zoom in" to see the diagram.
Diagram ref no 10.
- 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 GT3 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 GT3 2010-11
- 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
Fits:
Porsche 987 Boxster / S MKI & MKII 2005>>
Porsche 987C Cayman / S MKI & MKII 2006>>
Porsche 997 GT3 2007-2010
Porsche 997 Carrera 2/2S MKI & MKII 2005>> CABRIO/COUPE
This product supersedes Porsche's old part numbers:
- 99710662503
Click "Zoom in" to see the diagram.
Diagram ref no 10.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99710662504
The product you are viewing cross references to these numbers
- 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 GT3 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 GT3 2010-11
- 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
Fits:
Porsche 987 Boxster / S MKI & MKII 2005>>
Porsche 987C Cayman / S MKI & MKII 2006>>
Porsche 997 GT3 2007-2010
Porsche 997 Carrera 2/2S MKI & MKII 2005>> CABRIO/COUPE
This product supersedes Porsche's old part numbers:
- 997 106 622 03
Click "Zoom in" to see the diagram.
Diagram ref no 9.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99710662204
The product you are viewing cross references to these numbers