Electrolysis in cooling systems

[John Sherrow]

Anyone have any experience with this topic as it relates to cooling
systems? I've replaced a couple of radiators each one leaked at the
seams after about 6 months. Cooling system seems to work fine, car runs
between 1/4 to 1/2 on the gauge and the fan kicks on at the 1/2 way
point.

Should the radiator be grounded to the frame or isolated from it?
According to the info I've read you can check for electrolysis by
inserting a voltmeter positive lead into the coolant and tying the
negative lead to ground. My '86 5kcstq makes around minus .3 volts on
the meter when I do this. My other car makes minus .4 volts (7 year old
radiator). I've read that anywhere from .1 to .4 volts is bad. Not sure
about negative voltages.

Any insight would be appreciated.