1K0 121 407F – Expansion Coolant Tank (World Source)

Description

The 1K0121407F Coolant Tank by World Source is a direct-fit replacement designed to restore dependable cooling system operation. Specifically, this expansion reservoir accommodates the natural expansion and contraction of engine coolant under temperature changes. Furthermore, it maintains essential cooling circuit pressure and serves as the primary filling and bleeding point for the system.

Supplied by World Source to original equipment dimensions, this replacement unit mounts directly to factory brackets and hose fittings without modification. Additionally, it comes equipped with the integrated coolant level sensor for complete plug-and-play installation.

Signs Your Coolant Tank Needs Replacing

Inspect your engine bay if you experience any of these common warning signs:

• An illuminated low-coolant warning light on the instrument cluster despite adequate fluid levels.

• Visible hairline stress cracking, severe plastic yellowing, or brittle texture across the tank body.

• Active coolant weeping or dried crusty residue along the tank molding seams.

• Puddles or drops of pink or violet coolant collecting beneath the front passenger side of the engine bay.

• A strong, sweet coolant odor coming from under the hood after driving.

• Air intrusion into the cooling circuit causing elevated engine temperatures or gurgling heater cores.

Key Features of the 1K0121407F Coolant Tank

• OE Part Number: 1K0 121 407 F

• Supplier: World Source

• Sensor Included: Comes with the integrated dual-pin fluid level sensor.

• Function: Regulates coolant expansion volume, maintains operating pressure, and monitors fluid levels.

• Material: Virgin high-grade thermal plastic engineered to resist heat fatigue and chemical degradation.

• Fitment: Direct OEM bolt-on replacement matching factory mounting holes and quick-connect hose barbs.

Service Notes

Always verify fitment by VIN before ordering. Never remove the reservoir cap or disconnect hoses while the cooling system is hot or pressurized, as hot fluid can cause severe injuries.

Compatibility

Always verify fitment by VIN before ordering. Compatibility depends on platform generation (including MK5 and MK6 vehicles), engine displacement, and original installed tank revision.

Cross Reference

• 1K0 121 407 F