I have a 2011 6.4 hemi swapped into in a 69 truck, and a griffen radiator. with engine not running, and cool coolant. 100MV.
warm engine and coolant circulating. I get a radiator Eating reading of 650mv

get a sacrificial zinc anode for the radiator.

like this:
http://www.jegs.com/i/Fluidyne/091/FHP32...2m_BxoC8jLw_wcB

What does it read with no battery connected?

Kevin

Seems like a good reason to add grounds. Engine head or block to front frame rail (heavy gauge... #6 preferred). Engine head or block to rad support (min #10). Rad support or engine to radiator min 10 gauge. Engine to alternator backup ground (10 gauge min). Assumes the battery is already well grounded to the block/head (min 4 gauge).

I like to clean ground locations with a flat file or light touch with a die grinder and apply some grease or anti seize before torquing down the ground fastener.

I used a zinc anode it looks like new, i have added grounds and moved them around to different spots. still the same readings. i also removed the coolant and replaced it with RO water and royal purple PURPLE ICE......didnt help.

Sounds like you have a stray voltage if you are getting that much of a change in voltage while running. More going on than the fluid in the radiator.

I do not get a major difference in voltage. I'm around 80mV with less than 10mV change when running and hot.

I have a couple Justice Brothers products that might help, but they are not going to fix a bad ground. They are specifically made to reduce electrolysis with metal deviators to help with grounding between dissimilar metals.

I was just reading a similar story in FBBO about an electrolysis issue. His problem was due to lack of/bad grounds and faulty switches causing feedback.

He was getting a whole 3 volts of stray voltage in his cooling system. He said he fixed a bunch of grounds and went through his electrical system circuit by circuit. That knocked him down to .3 volts, but he would still get an increase/jump in stray voltage to .8 volts when the car was running and being started. That lead him to replacing the old ignition switch.

Wonder if 70blackfish could bypass the switch or "ignition on" related items and see if things changed. Might not be so easy with a car with modern electronics though?

Isolate the radiator from the body. Rubber mounts etc. If running an electric fan isolate it. If all else fails run a strap from the radiator to ground with an anode/cathode hold down. We call it cathodic protection in the oil field pipe lines. Can be difficult to run down.

once the motor is up to temp, radiator has voltage even with battery removed.

like the radiator has turned into a battery

If you have a zinc anode, relax and forget about it.....check the anode in a couple years.

I can't relax, i have zinc anode, looks like new....

The zinc will not eliminate the voltage as it decays, it will simply become the #1 target and decay before anything else does. Just because the voltage is there does not mean it is eating your aluminum parts (YET), and the rate of decay on the anode will be quite slow. Have you lost a heater core or radiator since the anode was installed?

Maybe you need to go to Hollywood.




























Sorry, as you were...

TWO radiators in 5 months, both the same model griffen.

the electrolysis is NOT eating the radiator, that why you have the zinc anode.....quit worrying about nothing.

He has an anode. It's been in the last two radiators that have holes eaten through them!

He cannot currently drive the vehicle with holes leaking fluild out of the radiator.

When I was fighting this battle with my Dakota. I found this site http://www.sancarlosradiator.com/VoltageDrop/index.html but what I believe solved my problem was a good flushing and getting a new battery.