My Radiator is a battery

[pneall]

Need some advice please.

Started out looking for stray current and just happened to check voltage from fluid in radiator to earth. Got a reading of 0.5 volts.

This is with battery disconnected.

As I have a new alloy radiator this is a great concern.

Everything is alloy ie block heads radiator with only dissimilar metals being top radiator pipe (Stainless) temp probes (brass)
water pump impeller (cast iron?).

Drained out radiator and flushed a few times, then just put water in . Re tested and got 0.01 volts.

What is permissable voltage??

The coolant was manufacturers approved .

Any one had this problem before? Know how to fix it?


Phil.

[boxhead]

I have seen it before with non genuine coolant in holden V6 commodores.

[MOTORHEAD]

Is the radiator mounted in rubber grommets? Try running a ground strap from radiator to eng block, see what happens to voltage. If you can't get rid of all the voltage, you might try a zinc anode in the radiator a-la marine engine cooling systems. They are available to screw into a threaded boss in the engine or heat exchangers(radiator) If you don't have an extra boss on the radiator, replace the drain plug with the anode. The anode won't get rid of the stray current, but it sacrifices itself to save the other metals in contact with the water, and it must be replaced periodically.

[pneall]

Motorhead, Yes radiator is rubber mounted.

Thanks for advice.

Phil

[Aussie Mike]

The more I think about it the more I agree with Motorhead. Running a strap from the engine to the block should put them at the same potential and stop any current flow.

Cheers

[Aussie Mike]

I just had a chat with Norm at Aussie Desert Cooler about testing for stray voltage. Most auto manufacturers allow a maximum of 0.4V but once the car is out of waranty who cares. Norm recomends zero Volts. He says to test it, fill the cooling system with just clean water and then connecting a volt meter to chassis ground and the other probe to your radiator. Turn your ignition on, fire up the car and turn everything on and check the voltage.

If you are measuring stray volts turn things off one at a time and see what makes a difference. Norm says the problem is usually caused by bad earthing in the wiring loom.

Cheers

[Bathrone]

Stray currents and aluminium is an evil, it can cause premature failure.

[Turk]

Radiator may be mounted by rubber grommets, but there is usually one or more cotter pins than secure it in place.

Electrolysis!!. Would it not make some sense to put in a sacrificial anode (zinc)?

TURK

[Fred Douglass]

Phil,

Listen to the "anode advice" in the above responses---as we boaters say: "Zinc or Swim". You may find that there are grounding and sacrificial-anode wiring kits available. I have seen some pretty exotic stuff on yachts which stay in salt water for protracted periods.

G'luck!

[o'brien]

Electrolysis is a big problem in diesel engines also. My trucks run a product called norcool to help stop this. Going to get my car going again after 5 years on blocks and will use distilled water, norcool, and probley a pressure cap with self destruct anode.

[sevenohms]

I can be wrong but I believe the cause for this is the stainless top pipe, electrochemically reacting with the aluminium block.

I can only think the reason for this going away is due to the Manganese (in the stainless) being removed (from the surface) and thus causing the reaction to stop.

Next time you have the top hose off have a look inside, I'd be curious to know if it looks different (maybe black or tan tinge)

[lineslinger]

Too much analysis,
You have a ground problem, something somewhere is not grounded, that is why you have voltage bleeding in an uncrontrolld manner, chase it down circuit by circuit by circuit.
Good Luck

[pneall]

Removed top SS pipe and noted some corrosion to SS pipe. This pipe now replaced with aluminium one.

Redid all earths and fitted radiator cap with anode dangling from it.

Will get auto elec to check all circuits and see if any improvement.


Phil

[Mando]

Hi Phil,

is the cap and anode something you made or bought? Can you give us some details?

Regards.

[jams]

There was an article in the car care section of Popular Mechanics a month or two ago.

[pneall]

Mando,

Don Pilling at Sanake bite sourced it for me. About $25.00.

Phil