I HAVE seen a water pump impeller rust off in the Vulcan...part of the reason mine got so hot when I first bought the car. (picture if you want to see)
Anyways, I have a similar question. Yesterday I drove from Sweetwater to San Angelo and back and on the way to San Angelo I pushed the car up to 90 mph passing someone and it got hot fast. I let it cool off and checked the fluids, all were fine. Is there a 'natural' limit of the 3.0 Vulcans? Also, it ran warmer then normal since then. On the way back to Sweetwater it ran warmer then norm (norm on mine is around the 20mph mark) also it was pretty chilly outside. Does that have anything to do with it?
P.S. my heater would run hot for a bit but it soon cooled off (during the day) tho during the drive back at night it stayed hot and then warm...ish but cooled off as well (just took longer). Any ideas with this would be nice too.
Let me guess, your degass tank was completely brown with gunk when you
changed the water pump? Unfortunately, you may have a head gasket
change on your vulcan in the future. If you look in the bone yard, and good percentage of vulcans there died by head gasket failure and brown
cruded up degass tanks due to lack of coolant changes and maintenance.
I would get a chemical flush done, flush the heater core again, and put
in new coolant and pray. YOU may also want to remove the lower cover below the radiator and flush out the radiator and AC
up front with hose and nossel.
You may also confirm that your trannie is truly locking up the TC at high
speeds. A unlocked TC will generate a lot more heat in the cooling system