[Smith1000]

I had the exact same problem on my 97 Lesabre about a year ago. I would fill it and it would leak down. Turned out the pump was leaking out the fluid. It took awhile to figure out where it was coming from. I thought it was leaking around the rubber grommet. I got a new pump at Advanced Auto. It did not cost much. I think it was 5 or 6 dollars and had a new rubber grommet with it. Replaced the pump, grommet and reattached the hoses and wires and it has been fine. I did not need to replace the reservoir. Turned out to be a fairly simple fix.