Join Date: Jun 2008
Location: Lethbridge Alberta
Model: 1999 GL1500 SE 50th Annv.
Sounds like water is getting by the seal on the shaft. There are a couple of places the water & oil can get together in and around the water pump area. The loose propeller is telling you that the seal/bearing is shot & that's where the water is getting into the oil.
Replacing the pump & O ring/gasket kit should solve your problems. I wouldn't go any further than that until I ran it after the R & R to see if that solved my problem.
1983 GL1100, 2013 Suzuki Vstrom DL650
Previous bikes - 1971 BMW R75, 2008 HD Softail, 2000 BMW R1100R, 1980 XJ650, XT500, GS550, 77 GL1000 x2 and a few others