John,
  You can try getting a new sensor, but make sure it has the right rubber O ring, and put a little lube (Vaseline) on it before screwing it down. Not to tight. If it leaks, you need a bigger (larger thickness, not diameter) O ring. I had to get my sensor at the dealership ($23  I think) to get one that had the right O ring, and it turned out to be a superior part as well.

  If the expansion tank is old (5+ yrs?) get a new one.
  Steven

John Drew <john.p.drew@GMAIL.COM> wrote:
  Hi again:
So it turns out that the coolant reservoir (not the one behind the plate)
is leaking from the top, and not from below the top pressure cap but out of
the place where the sensor is located- does this mean i need to replace the
sensor mechanism or is it possible that it just needs to be fastened more
securely into the tank? I have yet to disconnect all the hoses and try to
pull the entire reservoir out to inspect it further- thoughts? As always,
many thanks for your feedback.
- the border stories team

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