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Finn Lassen wrote:
David Carter wrote:
3. However, with ref to my last input, "coolant level", as sensed inside a
"pressurized" coolant expansion tank - IF mounted with coolant level up near
top of engine , will be the ABSOLUTE first AND BEST indicator of a leak:
Coolant leaks out - anywhere, that coolant is replaced by coolant in
"expansion/reservoir/pump header" tank until tank empties/turns on "Low"
light. Up to this point, the engine is FULL of liquid - no air, no nucleate
boilng, no temp jiggles. Then subsequent leakage will be out of engine, as
"expansion/reservoir" tank is now empty - THEN, the PRESSURE jiggles will
start.
David
However, there is one failure mode (with which I'm intimately familiar) where sensing the coolant level in the overflow bottle (and possibly in pressurized expansion/header tank) will not help: Blowby from compression and/or combustion gasses forcing air into the coolant system (and the coolant out). Actually a nice big header tank might be able to handle or hide it and then a increasing pressure trend would be the clue that it's getting worse and worse.
Finn
Finn, I have personal experience with that failure mode as well. I have a relatively small overflow bottle, with the Mazda snap-on cap from the car. It has a vent outlet on it, I have this vent hooked up to a short hose and a small aluminum tube that protrudes out of the cowl near the right wing root. I can look over my shoulder while flying and see this vent. If the overflow bottle fills up and coolant starts coming out of this vent, I know things are not normal.
--
Perry Mick
http://www.ductedfan.com
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