The coolant reservoir is diagnosed to be leaking and intended to be replaced.
May be caused by the coolant hose between coolant reservoir and radiator or the coolant hose between coolant reservoir and engine which may have internal cracks.
Internal cracks can cause coolant to get inside the coolant hose material and leak from connections to the coolant reservoir (arrows) due to the capillary effect.
• VAG1274 Cooling system tester
• VAG1274/8 Adapter
• VAG1274/9 Adapter
Before replacing coolant reservoir:
• Check if coolant hose between coolant reservoir and radiator is leaking at connection to coolant reservoir.
• Replace that coolant hose if necessary.
• Run engine or drive vehicle until coolant reaches a temperature of 80°C (176°F).
Coolant reservoir, checking for Leaks:
• Remove filler cap on expansion tank.
• Install tester VAG 1274 and adapter VAG 1274/8 on expansion tank (see illustration).
• Build up a pressure of approximately 1.0 bar with hand pump on tester.
If this pressure is not maintained:
• Trace and repair leaks.
• Check if any coolant leak around coolant reservoir still exists.
Pressure relief valve in filler cap, checking:
• Screw filler cap onto tester with adapter VAG 1274/9.
• Install hand pump and build up pressure.
• Pressure relief valve should open at 1.4 to 1.6 bar.
• Replace filler cap if necessary.
DO NOT replace coolant reservoir if there is no further coolant leak around the coolant reservoir detected.
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