I have an
engine guard on my primary
engine and it has paid for itself already going off well in advance of the engine
overheating by simply clamping the
sensor probe after the mixing
elbow.
Something reduced
water flow -
exhaust water temp increased and
alarm activated.
Its not pretty, its surface mounted but it works.
https://engineguard.com.au
Pretty simple device so that had me looking for a
diy ish alternative for the genset and something i could panel mount and I found this
AutoSpeed - $25 Temperature Controller and Display!
Bought it, a piezo buzzer and a longer probe to reach down a
deck level and wired it up as per directions but temp adjusted back to 47c.
Works a treat.