Coolant Hoses - Engine Bay

Water Hose that fits to the Water Pump part number 99610601157.



Fits:
Porsche 996 C2 / C4 / C4S 2002-05 3.6L

It's recommended to buy pipe 99610685103 along with this part.

This product supersedes Porsche's old part numbers:
- 99610685001
- 99610685005

Click 'Zoom in' to see the diagram.
Diagram ref no 18.

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Related, superseded, cross reference or alternative numbers for comparison.

99610685006

The product you are viewing cross references to these numbers

Water hose that fits to the water pump part number 99610601176.



Fits:
Porsche 996 Turbo 2001-05

Click 'Zoom in' to see the diagram.
Diagram ref no 23.

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Related, superseded, cross reference or alternative numbers for comparison.

99610625074

The product you are viewing cross references to these numbers

Water hose that fits to the water pump part number 99610601176.



Fits:
Porsche 996 Turbo 2001-05

Click 'Zoom in' to see the diagram.
Diagram ref no 23.

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Related, superseded, cross reference or alternative numbers for comparison.

99610625074

The product you are viewing cross references to these numbers

Water Hose Return Line. 

The Porsche Water Hose Return Line 99610682204 is a genuine Porsche replacement coolant hose used within the engine cooling circuit on selected Porsche 996 and 997 models.

Fits:

• Porsche 996 C2 3.6L 2002-2005
• Porsche 996 C4 3.6L 2002-2005
• Porsche 996 C4S 3.6L 2002-2005
• 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  

Diagram Ref No 33

The hose forms part of the coolant return side of the system, carrying coolant back through the cooling circuit after it has passed through associated engine, radiator or heating-system components.

Maintaining this hose in good condition is essential because the Porsche cooling system operates under pressure and relies on a completely sealed circuit to maintain stable engine temperature.

This Genuine Porsche replacement provides the correct factory-style dimensions, connections and routing for the intended application.

What This Product Does:
The return hose carries coolant through the return side of the vehicle's liquid-cooling system.

Its main functions include:

• Carrying coolant through the return circuit
• Maintaining continuous coolant circulation
• Helping maintain correct cooling-system pressure
• Returning coolant toward the engine or associated cooling circuit
• Supporting stable engine operating temperature
• Preventing coolant loss when correctly sealed
• Maintaining the original Porsche coolant routing
• Connecting adjoining coolant pipes and cooling-system components

The hose works together with the supply hose, coolant pipes, water pump, thermostat and radiators to maintain controlled coolant circulation.

Symptoms Of Wear Or Failure:
Coolant hoses deteriorate over time because of heat, pressure, vibration and repeated thermal cycling.

Common symptoms include:

• Visible coolant leakage
• Wetness around the hose or connections
• Pink, white or crusty coolant residue
• Falling coolant level
• Frequent coolant top-ups
• Low coolant warning
• Sweet coolant smell
• Cracks in the hose surface
• Hardened or brittle rubber
• Swollen or unusually soft hose sections
• Bulging under pressure
• Damaged hose ends
• Leakage around clamps or joints
• Fluctuating coolant temperature
• Engine running hotter than normal
• Steam or coolant vapour after driving
• Engine overheating

A small leak may only appear when the engine is fully warm and the cooling system is pressurised.

Why Replacement Matters:
A deteriorated coolant return hose can fail gradually through seepage or suddenly through a split or rupture.

Loss of coolant can quickly compromise the engine's ability to control temperature.

Continued driving with a leaking hose can result in:

• Cooling-system pressure loss
• Reduced coolant circulation
• Air entering the cooling system
• Engine overheating
• Poor heater performance
• Coolant warning messages
• Roadside breakdown
• Serious engine damage if overheating is allowed to continue

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

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

99610682204

The product you are viewing cross references to these numbers

Water hose, Feed.



Fits:
Porsche 996 Turbo 2001-05
cars with 6-speed manual transmission (option code: 480)

Click 'Zoom in' for large parts diagram.
Diagram ref no 3

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

99610674174

The product you are viewing cross references to these numbers

Water hose. Engine Supply Pipe to Main Supply Pipe.



Fits:
Porsche 996 C2 1998-05
For Rear-wheel drive cars (I338)

Click 'Zoom in' for large parts diagram.
Diagram ref no 1

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

99610664056

The product you are viewing cross references to these numbers

Water hose for cars with Tiptronic gearbox



Fits:
Porsche 996 C2 / C4 / C4S 1998-05 Tiptronic Gearbox

Click 'Zoom in' to see the diagram.
Diagram ref no 33.

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

99610622266

The product you are viewing cross references to these numbers

Water hose for cars with Tiptronic gearbox
High-quality OE Match coolant hose engineered to match the original Porsche specification for fit, flexibility, and durability. It is designed for the Porsche 996 (911) 1998–2005 with Tiptronic automatic transmission, and carries coolant within the engine’s cooling circuit to maintain proper operating temperatures. It installs directly in place of the original hose with no modification required, ensuring correct coolant flow and long-term service life.

Fits:
Porsche 996 C2 / C4 / C4S 1998 - 2005 Tiptronic Gearbox

Diagram ref no 33.

The Porsche 996’s water cooling system is responsible for regulating engine temperature under all driving conditions - from cold starts to high-speed touring. The water hose is a critical link in the coolant circuit, connecting key components such as the water pump, thermostat housing, radiator, and cylinder head.

Over time, heat cycling, pressure fluctuations, and environmental exposure cause hoses to age. Rubber can harden, swell, crack, or develop soft spots that lead to leaks, reduced coolant flow, or sudden failure. Because this hose operates under both thermal and pressure stress, deterioration can compromise cooling performance and increase the risk of engine overheating.

The water hose:
•  Carries pressurised engine coolant between major cooling system components
•  Maintains consistent coolant flow for stable temperature control
•  Withstands heat, vibration, and pressure from the engine’s cooling system
•  Helps prevent overheating and protects engine components

A compromised water hose can lead to:
•  Coolant leaks
•  Reduced heating efficiency
•  Engine overheating
•  Loss of pressure in the cooling circuit

Replacing old or degraded hoses with an OE Match water hose helps maintain coolant flow, preserves optimal engine temperatures, and prevents unexpected breakdowns due to hose failure.

Replace this water hose if you notice:
•  Visible cracks, soft spots, or swelling
•  Coolant leakage at hose ends
•  Unexplained engine overheating
•  During water pump or thermostat service
•  As part of preventative maintenance on higher-mile vehicles

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

99610622266

The product you are viewing cross references to these numbers

Water hose. Engine supply pipe to main supply pipe.



Fits:
Porsche 996 C2 1998-05
For Rear-wheel drive cars (I338)

Click 'Zoom in' for large parts diagram.
Diagram ref no 1

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

99610664056

The product you are viewing cross references to these numbers

Water hose for cars with manual gearbox.



Fits:
Porsche 996 C2 / C4 3.4L Manual Gearbox

Click "Zoom in" to see the diagram.
Diagram ref no 33.

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

99610622265

The product you are viewing cross references to these numbers

Water hose for cars with manual gearbox.
It provides reliable coolant flow between the engine and the heating/cooling system, maintaining optimal operating temperature and engine performance. Manufactured to match the original equipment’s material specification, bend geometry, this hose delivers a direct fit and factory-style durability.

Fits:
Porsche 996 C2 / C4 3.4L Manual Gearbox
Up to model year 2001

Diagram ref no 33

• Position on Vehicle: Located within the engine cooling circuit, this hose connects key engine cooling components and is mounted in the front engine bay.

• Cross-Reference / Alternative Numbers: Part number 996 106 222 65 (99610622265) — includes superseded numbers such as 99610622252, 99610622254, 99610622256.

• Applications: Ideal for when the original hose has become brittle, swollen, leaking or is due for renewal during engine service or cooling system overhaul.

The coolant hose is vital in maintaining proper engine temperature, protecting against overheating and ensuring the cooling system works as designed. A worn or damaged hose can lead to coolant leaks, engine overheating, poor heater performance or even severe engine damage. Replacing restores secure coolant flow, prevents failure and ensures your Porsche runs reliably.

When and why to replace:
• Visible cracks, bulging or brittleness in the original hose.
• Coolant leakage or low coolant level with no obvious external damage.
• Heating or cooling performance has reduced (e.g., slow warm-up or overheating).
• During scheduled cooling system service or when replacing other cooling system components.
• High-mileage vehicles where original hoses are showing signs of age and fatigue.

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

99610622265

The product you are viewing cross references to these numbers

Water hose. Porsche 996 C2 / C4 3.6L Manual Gearbox



Fits:
Porsche 996 C2 / C4 3.6L Manual Gearbox

Click "Zoom in" to see the diagram.
Diagram ref no 33.

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

99610622267

The product you are viewing cross references to these numbers

Water Hose.

Fits:
Porsche 996 Carrera 2/4 3.4L 1997>>2001
Porsche 996 Carrera 2/4 3.6L 2001>>2005
Porsche 996 Carrera 4S 3.6L 2001>>2005

Diagram Ref No 29

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

99610623351

The product you are viewing cross references to these numbers

Water pipe, return. 

Fits:
Porsche 996 3.6L 2002>>
with 6-speed manual transmission

Diagram ref no 32

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

99610624354

The product you are viewing cross references to these numbers

Water pipe, return.



Fits:
Porsche 996 Turbo / GT2 2001-05
Porsche 996 GT3 3.6L 1999-05

Click 'Zoom in' for large parts diagram.
Diagram ref no 20

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

99610625471

The product you are viewing cross references to these numbers

Water pipe.



Fits:
Porsche 996 Turbo / GT2 2001-05
Porsche 996 GT3 3.6L 1999-05

Click 'Zoom in' for large parts diagram.
Diagram ref no 19

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

99610605270

The product you are viewing cross references to these numbers