Coolant hose. Porsche 986 Boxster › 99610650206

This OE Match coolant hose connects the thermostat housing to the water pipe on the listed Porsche 986 Boxster models. It forms part of the engine cooling circuit, carrying coolant through this connection.

Fits:

• Porsche Boxster 986 2.5L 1997–99
• Porsche Boxster 986 2.7L 1999–02
• Porsche Boxster 986 2.7L 2003–04
• Porsche Boxster S 986 3.2L 1999–02
• Porsche Boxster S 986 3.2L 2003–04

Diagram Ref No 3

Check fitment for your specific vehicle (model, year, engine) before ordering.

What Is This Part?
This is the connecting hose between the thermostat housing and the water pipe in the engine cooling assembly. Its flexible connection allows coolant to pass between these components while accommodating small movements at the joint. The hose ends work with the connecting surfaces and hose clamps to retain coolant. When investigating leakage in this area, the hose, clamps and adjoining connections should be checked together, as deterioration in any of them can cause seepage. 

What Does This Part Do?

• Connects the cooling circuit: Joins the thermostat housing to the water pipe.
• Carries coolant: Provides the fluid passage between these two cooling-system components.
• Forms a sealed connection: Works with the adjoining fittings and correctly fitted clamps to contain coolant at the joints. 

Why Replace This Part?
Repeated exposure to heat can leave a coolant hose hardened, cracked, swollen or unusually soft. Rubbing against nearby components can also wear through the outer surface. Replacement is appropriate when inspection confirms damage or leakage from the hose itself, rather than simply because another cooling-system component is being renewed. 

Check the adjoining fittings and clamps before installing the replacement. A damaged connector or unsuitable clamp can leave a new hose leaking, so correcting the underlying cause is part of the repair. ()

When to Replace This Part?

• Confirmed leakage: Fresh dampness, drips or coolant deposits traced to the hose body or its ends.
• Cracking or hardening: Visible splits or a hardened outer surface, particularly around bends and connections.
• Swelling or soft spots: Bulging or unusually spongy sections that suggest deterioration.
• Abrasion: Rubbing marks or worn areas where the hose contacts nearby parts.
• Damage during removal: Torn ends or other damage that prevents the hose from seating properly when refitted.

These are inspection indicators, not proof that this hose is responsible for every coolant-loss complaint. Heat damage, abrasion and leakage at connections are recognised coolant-hose failure patterns. 

Where Is This Part Fitted?
Location: In the engine cooling assembly, between the thermostat housing and the water pipe.

Product Summary

• Product: Thermostat housing-to-water pipe coolant hose.
• Brand: OE Match.
• Part reference: 99610650206.
• Related references: 99610650204, 99610650203.
• Purpose: Connects the thermostat housing to the water pipe within the cooling circuit.

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

99610650206

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