94 Audi Cabriolet - Coolant Leak

Hi

I have noticed the coolant-level light flashing on my dashboard
recently. The coolant reservoir is leaking, and needs frequent top-ups.
My mechanic replaced the reservoir cap, to no avail. A pressure-test
did not reveal any leaks in connecting hoses.

I examined the underside of the coolant tank, and discovered that fluid
seems to be leaking from the base of the tank, where the wires for the
*electrical sensor* that detects low coolant level actually enters the
tank.

Is there a way to this seal up, or do I need to replace the entire
coolant reservoir?


Thanks,

Andrew.