"DSK" wrote in message
. ..
Scout wrote:
How many here have a hot water heater that works with the engine's
coolant system as a heat source?


Prob'ly everyone with a water heater. It's extremely common.


It is a very thin line separating that toxic material from your drinking
water supply. The closed engine coolant loop may reach 15 psi when hot,
and could easily outmatch the force in the fresh water system, especially
if you run dry or turn off your on-demand pump for any reason. A pin hole
or a crack in the hw heat exchanger could have deadly results.


True, unless you use non-toxic anti-freeze.

In my work as a boiler tech, we were never permitted to use toxic
anti-freeze in boilers that produced domestic hot water (summer-winter
boiler packages). I've replaced tens of those coils due to leakage!

That's a good idea. It's also a good idea to make it part of your regular
maintenance checks, insure no crossover between the systems.

It's those precious moments between the birth of a leak and the discovery of
it that worry me!