Engine coolant cap Coolant expansion tank cover for Volvo Radiator Cap OE 30811055 Sealing cap

Product Description:

Coolant expansion tank cover
OE NO.: 30811055

Applicable vehicle type: For Volvo

The coolant expansion tank cap is a critical sealing and pressure control component of the automotive cooling system, installed on the top of the expansion tank (also known as the auxiliary reservoir or coolant recovery tank).

Main Functions:

1. Sealing the System: Prevents coolant leakage and maintains the closed nature of the cooling system.
2. Pressure Regulation: Maintains standard pressure within the cooling system to avoid excessive pressure causing pipe rupture or coolant boiling.
3. Safe Pressure Release: When pressure becomes too high, the expansion tank cap automatically releases excess pressure to ensure safety.
4. Preventing Air Ingress: Prevents air from entering the cooling system, avoiding bubble formation that can impair heat dissipation efficiency.

Fault Warning Signs

1. Frequent Reduction in Coolant Level: Check the cap's seal integrity and pressure valve functionality.
2. Insufficient System Pressure: May lead to boiling and overheating.
3. Inability to Release Excess Pressure: May result in pipe rupture.

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