"Engine Preheat" vs. "Engine Heater"

[martingregg598]

Hi Pete, on my 95 BMC 37' the Aqua Hot engine preheat loop runs through
the dash heater core, so if I have the dash heater, hot-cold lever in
the cool position the valve is closed and the hot engine coolant coming
through the Aqua Hot to the dash heater can't pass through back to the
engine, no loop. I discovered this one day when I had the A/H engine
preheat on and I was playing around with something under the dash and
felt the hot line on one side of the valve and cold on the other. I
can't help but wonder if the installers at BB put all of the A/H
plumbing in the same way? My instruction manual says not to have the
A/H engine preheat on while the engine is running. Good Luck.
Marty Gregg
95 BMC 37
Kennewick, WA.