Coolant Hoses - Engine Bay

Coolant hose - elbow. Coolant supply hose for oil pump housing.



Fits:
Porsche 996 3.4L/3.6L C2 / C4 / C4S 1998-2005
M 66X 01815 >>

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Diagram ref no 29

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99610623356

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Coolant hose - elbow. Coolant supply hose for oil pump housing.



Fits:
Porsche 996 3.4L/3.6L C2 / C4 / C4S 1998-2005
M 66X 01815 >>

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Diagram ref no 29

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99610623356

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Coolant hose, return, LEFT.



Fits:
Porsche 996 C4 / C4S 1998-05
All-wheel drive (option code: 339)

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Diagram ref no 11

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99610672806

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Coolant hose, return, LEFT.
Left Side Return Hose, From right side radiator return pipe to under car return pipe.



Fits:
Porsche 996 C4 / C4S 1998-05
All-wheel drive (option code: 339)

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Diagram ref no 11

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99610672806

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Coolant hose, supply.
From feed pipe.



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

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Diagram ref no 27

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99610621260

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Coolant hose, supply.
From feed pipe.



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

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Diagram ref no 27

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99610621260

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Coolant hose, Supply. RIGHT.



Fits:
Porsche 996 Carrera 1998-05
Porsche 996 Turbo 2001-05

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99610672305

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Coolant hose, Supply. RIGHT.
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

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Coolant hose, Supply. RIGHT.
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

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Coolant hose. From engine to water supply pipe.
Radiator coolant hoses are vital conduits within the engine cooling circuit. They transport engine coolant between the engine and radiator, allowing heat absorbed in the engine block to be released via the radiator.

Fits:
Porsche 996 C2 / C4 3.4L 1997 - 2005

Diagram ref no 23

Radiator coolant hose – connects radiator and engine coolant passages as part of the primary cooling loop.

Function:
• Circulates coolant between the engine and radiator
•  Helps maintain optimal operating temperatures
•  Prevents coolant leaks and pressure loss
•  Contributes to engine reliability and longevity

Radiator hoses are continuously exposed to elevated temperatures, pressure fluctuations, and corrosive coolant chemicals. Over time, hoses can weaken, crack, swell, or become brittle, leading to:
•  Fluid leaks Engine overheating
•  Loss of coolant pressure
•  Potential engine damage.
Replacing aged or damaged hoses ensures the cooling system maintains integrity, prevents leaks, and continues to operate as intended by the manufacturer.

Replace this radiator coolant hose if:
•  Visible cracking, bulging, or soft spots
•  Evidence of coolant seepage or wet residue
•  Hoses feel mushy or stiff when squeezed
•  During routine coolant service or before long-term storage
•  If coolant system overhaul is being performed

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99610650156

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Coolant hose. From engine to water supply pipe.



Fits:
Porsche 996 C2 / C4 3.4L 

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Diagram ref no 23

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99610650156

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Coolant return water hose.



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

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Coolant Return Water Hose

Maintain the reliability and efficiency of your Porsche's cooling system with this OE Match Coolant Return Water Hose. Manufactured for precise fitment and long-lasting durability, this replacement hose restores the correct circulation of engine coolant between key cooling system components, helping to regulate engine temperature under all driving conditions.

The cooling system on the Porsche 996 is critical to protecting the M96 engine from excessive heat. The coolant return hose carries coolant back through the system after it has absorbed heat from the engine, allowing it to be cooled by the radiators before recirculating. Over time, the original hose is subjected to constant heat cycles, coolant pressure, vibration and age, causing the rubber to harden, crack or weaken. If left unchecked, this can result in coolant leaks, pressure loss and ultimately engine overheating.

Replacing ageing coolant hoses is an important part of preventative maintenance and is highly recommended during engine repairs, cooling system overhauls or whenever signs of deterioration become evident.

Manufactured to OE Match standards, this coolant return hose provides dependable sealing, excellent durability and factory-quality fitment for long-term reliability.

What Does the Coolant Return Water Hose Do?

The coolant return hose forms part of the engine's closed cooling system, allowing coolant to circulate efficiently between the engine and cooling components.

Its primary functions include:

• Returning coolant through the cooling circuit.
• Maintaining continuous coolant circulation.
• Helping regulate engine operating temperature.
• Supporting efficient heat transfer.
• Maintaining cooling system pressure.
• Preventing coolant loss from deteriorated hoses.

A correctly functioning coolant hose is essential for maintaining engine efficiency and preventing overheating.

Why Replace the Coolant Return Water Hose?

Rubber coolant hoses gradually deteriorate through exposure to heat, pressure and coolant chemicals.

Common reasons for replacement include:

• Cracked or perished rubber.
• Coolant leaks.
• Soft or swollen hose walls.
• Internal hose degradation.
• Cooling system pressure loss.
• Age-related deterioration.
• Cooling system refurbishment.
• Preventative maintenance.

Replacing worn hoses helps maintain the integrity of the cooling system and significantly reduces the risk of unexpected failures.

Symptoms of a Failing Coolant Hose

A deteriorating coolant return hose may cause:

• Visible coolant leaks.
• Sweet smell of coolant.
• Low coolant warning.
• Damp or stained hoses.
• Cooling system pressure loss.
• Rising engine temperature.
• Steam from the engine compartment.
• Risk of engine overheating.

Replacing the hose restores reliable coolant circulation and helps protect the engine from heat-related damage.

Benefits

• Restores cooling system efficiency.
• Helps prevent coolant loss.
• Supports stable engine operating temperatures.
• Reduces the risk of overheating.
• Straightforward direct replacement.
• Long-lasting, durable construction.

Whenever replacing coolant hoses, it is advisable to inspect the remaining coolant hoses, hose clips, thermostat, water pump, expansion tank and coolant pipe connections, as these components often age together and replacing them at the same time can help prevent future cooling system failures.

Why Choose OE Match Cooling System Components?

OE Match cooling system components are manufactured to deliver factory-quality fitment, dependable durability and reliable long-term performance. Designed specifically for Porsche applications, they help maintain the efficiency of the cooling system while protecting the engine from overheating. Whether you're repairing a coolant leak, carrying out preventative maintenance or undertaking a complete cooling system overhaul, OE Match components provide the quality expected by Porsche enthusiasts and specialist workshops.

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99610674110

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Coolant return water hose.

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

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Coolant supply water hose.
This Porsche Genuine OE Coolant Supply Water Hose is an original-equipment cooling system hose designed specifically for the Porsche 911 (996) Carrera 4 with the 3.4 L engine. Manufactured to Porsche’s factory specifications, this hose provides the exact fit, material quality, and durability required to maintain reliable coolant circulation within the engine cooling system.

Fits:
Porsche 996 C4 3.4L 1998 - 2001

Diagram ref no 1

This genuine Porsche hose replaces earlier part numbers 99610674003 and 99610674004, ensuring compatibility with the original cooling system design used in early 996 Carrera 4 models.

The coolant supply water hose carries engine coolant between key cooling system components, helping transport hot coolant from the engine to the radiator or distribution pipes where heat is dissipated. By maintaining steady coolant flow, it helps regulate engine temperature and prevents overheating.

A correctly functioning coolant hose ensures the cooling system maintains proper pressure and flow, allowing the engine to operate within its designed temperature range even under high load or spirited driving conditions.

Functions & Technical Role
•  Coolant transfer: Moves coolant between the engine and the main cooling supply pipes
•  Temperature regulation: Supports the cooling system in maintaining optimal engine operating temperature
•  Pressure resistance: Designed to withstand high coolant pressure and temperature cycles
•  Durable construction: Manufactured from heat- and ozone-resistant rubber compounds for long service life
•  OEM precision fit: Exact hose shape and connections to match Porsche’s original cooling layout

Fitment / Position on Car
•  Installed on: Engine cooling system
•  Location: Between the rear coolant supply pipe and the main distribution pipe / radiator supply line
•  Function: Forms part of the primary coolant circulation circuit between engine and cooling components.

Coolant hoses are exposed to constant heat, pressure, and vibration. Over time they can harden, crack, or leak, which may lead to coolant loss and potential engine overheating. Replacing worn hoses with genuine Porsche OE parts ensures the correct material quality, fitment, and durability required to maintain the performance and reliability of the Porsche cooling system.

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99610674006

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