ethylene glycol is highly toxic and it tastes sweet so be careful with it around pets.
Im amazed you couldn't find propyl but found ethylene, its usually the other way around.
AS i said the residue could be a result from your radiator flushing out whatever flux was left during the solder process.
It can take several hot water flushes to get rid of the residue, and even then you will still see it from time to time.
I would honestly not worry about it too much as it didn't discolor your water.
That is what you need to watch out for, is if your clear water has changed colors or to a milky appearance.
You really need temp probes to determine if a second radaitor is required, unless you are adding it to gain silence.
If your water coolant temp and ambient at radiator temp is within 2C of each other, a second radiator will only net you better acoustics, as you get flat into the extreme ranges of diminished returns.
Im amazed you couldn't find propyl but found ethylene, its usually the other way around.
AS i said the residue could be a result from your radiator flushing out whatever flux was left during the solder process.
It can take several hot water flushes to get rid of the residue, and even then you will still see it from time to time.
I would honestly not worry about it too much as it didn't discolor your water.
That is what you need to watch out for, is if your clear water has changed colors or to a milky appearance.
You really need temp probes to determine if a second radaitor is required, unless you are adding it to gain silence.
If your water coolant temp and ambient at radiator temp is within 2C of each other, a second radiator will only net you better acoustics, as you get flat into the extreme ranges of diminished returns.
