Product Introduction 1311211-KS1A0 Coolant Reservoir Cap is a pressure control cap for DFL heavy truck engine cooling expansion tank. It maintains rated pressure inside the cooling circuit to raise coolant boiling point and prevent liquid vaporization under high working temperature. This aftermarket replacement cap solves coolant leakage, pressure loss and continuous low-coolant warning triggered by failed pressure valve, aging sealing gasket and cracked cap shell of original reservoir caps, protecting engine from overheating and ensuring stable operation for long-distance heavy cargo transport vehicles.

Product Advantages High-strength engineering plastic housing resists thermal shock and chemical corrosion from antifreeze coolant. Built-in precision pressure valve automatically regulates internal tank pressure. Integrated rubber gasket delivers reliable sealing performance under engine vibration and temperature cycling. Each cap undergoes pressure performance testing before shipment, simple installation and helps avoid engine overheating failures caused by abnormal cooling system pressure.

Applicable Models Fit for DFL Dongfeng heavy truck series, matches original expansion tank assembly of engine cooling system for highway long-haul and bulk cargo transportation vehicles.

FAQ

Q1: What happens if the coolant reservoir cap fails to hold pressure?
A1: Coolant boils easily, liquid loss accelerates and engine temperature rises rapidly under load.
Q2: Can I reuse the old cap after cleaning the gasket?
A2: Temporary use may be possible; replace it once the rubber gasket hardens or loses elasticity.
Q3: What should I check when replacing the reservoir cap?
A3: Inspect expansion tank mouth for cracks and clean sediment around the sealing surface.
Q4: Why is pressure control important for heavy truck cooling system?
A4: Proper pressure increases coolant boiling point, preventing bubble formation and maintaining heat dissipation.