Radiator stop-leak?

[Doyt W. Echelberger]

I can't explain where about a pint of coolant goes every week.  No external
drips or puddles or wet spots.  After about 200 miles of driving, I have to
top up the overflow reservoir.

I know the answer is  "Find the leak and fix it."  But that doesn't seem to
be happening. I've been following the "coolant system gases-saga"  thread,
and I too may have a head gasket leak.  My cabin floor isn't wet.  My next
move is to get my mechanic to run a test on my coolant, for exhaust gases.
If that returns positive, I do a head gasket.  But if that returns
negative, I'll consider some kind of stop-leak. I've heard that car
manufacturers use it routinely in new cars, because they all leak.
(Probably a myth.)

Anyhow......Did anybody ever try that dry aluminum flake material in a
tube, that claims it will never harm anything in the coolant system?  Every
gas station carries it and it has been around for 50 years.

I figure the coolant is going somewhere that is hot enough to evaporate it,
and it only leaks out when the engine is running, and it gets blown away in
the stream of air that whips through the engine compartment. Maybe it gets
spread out on the surface of the hot engine, and gets evaporated that way.
And maybe it is getting pulled into a combustion chamber and becomes part
of the exhaust gases.

Anyhow, maybe some stop-leak will plug up whatever tiny channels are
causing this loss. But I'm not sure what else will get plugged up with this
powdered aluminum stuff. Channels in the heater core?  Opening in the
thermostat? Lines to the turbo?

Any bad experiences with stop-leak?

Doyt Echelberger
87 5ktq at 255k miles, in Ohio   USA