yup, the dingleberry came attached to the cap. it seems to be working, been there for 2 years and is under heavy attack. $30 to protect my $389 rad along with all the other wetted parts, well worth it.
Zincing the coolant system? Why didn't I think of that!? We use them on our boats all the time in salt water to prevent corrosion between dissimiliar metals.
Here's a primer for those who don't know what the process is. Galvanic action is caused when two diassimiliar metals are exposed to an electrolyte and an electrical current or field. The less noble metal will be sacrificed as it is stripped of its electrons. The further apart on the noble scale the metals are, the faster the degradation.
In a car you have:
1. Dissimiliar metals - steel, aluminum
2. Electrolyte - old, acidic coolant
3. Electrical current or field - Ground strap, alternator, sensors, ignition, short curcuits
Another tip I recently heard was to get those paper ph level strips to periodically test the coolant for acidity. Once it starts to rise, change it out.
I'm fairly cautious about bad coolant now since my aluminum heater core and rad dissolved in my F-150. No need for me to post those pics again.
You can actually measure the voltage differential by using a digital voltmeter. On newer vehicles (and would be applicable to our older ones, Ford recommends a maximum of ~ .4 volts. A shop I deal with had a vehicle that they replaced the heater core 3 times in 4 months due to electrolysis. When they measureed the voltage it was .7volts. simply ground one end of the voltmeter and (assume you have a scale small enough) stick the probe into the water.