John90XJ's possiblity sounds likely, one of the vacuum lines (from the cannister) is sucking fluid from someplace, probably one of the smaller lines or a vacuum actuator, the large vacuum line from the canister goes straight to the intake. The vacuum lines aren't that complicated, it's just that many are hard to get too.
Just about the time you think you've heard it all, somebody comes up with a new one. :wave:
You can usually tell coolant from the slippery feeling or the smell, if you do taste it, it's sweet :laugh3: .