This according to a "cooling system expert".

I had never heard this before. He said that the reason you see blown heater cores is because of the electrical charge within the radiator fluid in your cooling system. He says that if you dont have proper grounds (including wiring EVERYTHING back to the battery - IE stereos, radios, etc) then the fluid will slowly discharge in the heater core leading to a breakdown of the metal in the heater core - obviously then spilling everywhere.

He said the best way to see if you have to much charge - take a voltmeter, hook negative lead to battery, and positive into the radiator fluid. If you get anything over .4 volts, then you are asking for problems. (Of course, if you hook the positive lead to the positive terminal on the battery, and the negative into the fluid, you will get 12 volts). I did both my car and truck and came out to about .05

This sound true or a bunch of BS?

 

Just for yucks I thought Id measure the resistance of coolant and its about 200KOhms per inch. I suppose its possible for weak reactions to take place but Id probably put the effort into making sure the coolant is changed on a regular basis rather then trying to ground everything in the cooling system.

 

It is called "galvanic corrosion" and it is real. However, I don't know what battery grounds would have to do with it, my guess would be that battery grounds have nothing to do with it, as it occurs within the cooling system itself.Here's a decent explanation: Galvanic Corrosion

 

A downside to having a motor with iron parts?

 

You can talk about real effects and theories all day, but that isnt why your heater core will go out. A lot of the time it is because it is old, and rusts through. The #1 reason I have seen for failed heater cores though, is poor coolant system maintenance. Probably #1 Killer of all heater cores.

 

This is an artical in a back issue of Motor magazine.


Trouble Shooter
by Bob Savasta

May 2001. Aluminum heat exchangers have obvious benefits, but they're also more susceptible to corrosive damage caused by shoddy cooling system maintenance.
Corrosion Explosion
This question isn't about a particular year or make, but about vehicles in general. Over the last six years or so, I've seen a rather large number of clogged radiators and heater cores, particularly those made of aluminum. One of my fellow techs believes this to be the direct result of shoddy maintenance habits on the part of vehicle owners. While I certainly can't dispute that claim, I feel there's more to this problem than meets the eye-perhaps the aluminum content itself.

Two questions: Are aluminum heat exchangers more susceptible to corrosion problems? And if they are, is there anything we, as technicians, can do to ensure that they have the same life expectancy as older designs? As always, I look forward to your response!

John Gibbons
Denver, CO

Aluminum heat exchangers were introduced some years ago with a few obvious advantages over their copper/brass counterparts, John. Among the benefits are lighter weight, cheaper manufacturing costs and better heat transfer capabilities, which means engineers can spec out smaller components with equal performance characteristics-an absolute must in smaller, crammed engine bays.

One disadvantage of using aluminum as a heat transfer medium, however, is that it doesn't take kindly to old, worn out coolant. Remember, when antifreeze depletes over time, it not only loses its protective and lubricant qualities, but also tends to go toward the acidic side of the pH scale. While this can be problematic for copper/brass components also, it's especially devastating on aluminum heat exchangers, with clogged tubes, corroded passages and pitted or leaky tanks among the likely results.

Corrosive coolant coupled with inferior grounds can only compound the problem. This leads to a phenomenon known as electrolysis-a condition that sets up when the acidic coolant electrochemically reacts with the dissimilar metals (steel, aluminum, cast iron) in the engine and cooling system. This causes corrosion of the metal surfaces, which ultimately leads to the generation of stray electrical current in the system. In effect, the engine and radiator become a battery, with the coolant serving as a very willing electrolyte!

An easy test for electrolysis is to hook one DMM probe to battery negative while placing the other directly in the coolant. (Don't let the probe tip touch the radiator!) Like a voltage drop test, you'll want the engine running and as many accessories as possible on to load the circuits and get accurate results. What you're looking for is an upper limit of about 300mV, with under 100mV preferable. Above the 300mV max? Identify the problem circuit, clean its ground thoroughly with a wire brush, then retest.

Still above the 300mV threshold? Then it's time to swap out the old antifreeze for a fresh brew. Coolant flush/fill machines work great here because they not only exchange all the coolant in the system (typically in under 30 minutes), but do it within a closed-loop framework that prevents air entrapment from becoming a service issue that'll haunt you down the road.

If you don't have access to a power flush/fill machine, you have no alternative but to flush and refill the system manually. Remember, most radiators hold only about 40% of the total volume of the system, so you'll either have to pull the lower radiator hose or open the drain **** (if the engine has one) to get all the old coolant out. Once that's done, fill the system with clean water, start the engine, wait until the cooling fan cycles, shut the engine down, then drain again. By the way, many manufacturers recommend going through several of these cycles before adding antifreeze and buttoning the system up! Ready for that flush/fill machine now?

One last point: Always use the coolant formulation recommended by the carmaker, especially when the factory fill is an extended-life antifreeze. If you don't, you could be in for one nasty headache. As a case in point, GM's Dex-Cool has been known to cause head gasket and water pump failures on some Ford OHC V8s! Hey, nobody said it was gonna be easy, right?

 

Maybe ground the heater core?

 

No. If you do that you are just helping to complete the circuit. Check the voltage of your coolant per the article above. If it's been awhile it wouldn't hurt to flush and fill anyway. Also, clean all your exsisting grounds.

 

Or you could just maintain your coolant system in the first place, and not worry about voltages and other such garbage. Keep your coolant clean, and it wont cause problems.

 

its 100% true, i have seen bad coolant take out aluminum heater cores in less than 3 months. this was with the " long life " coolant before the coolant had gotten anywhere near the recommended
time or mileage to replace it.
besides the test that todd200 posted from motor mag, there is another test i also use which is the same as from that article but with everything turned off. like this .4 volts is also too much, same as from the article, at .3 it needs a through flush. i do both
because on occasion i have seen the voltage go down with everything turned on. like they said, antifreeze is an electrolyte, when it gets old it make it's own electricity. that same bad coolant can also take out that nice expensive aluminum radiator too.
and while your doing the flush, put a new radiator cap on there too, at 2 years of age, they have done their job. nothing like an old cap that decides to over pressure the system & start blowing
components out or under pressures & causes a over heating problem.

 

The point is, there is no electrical cure for it. It cant be grounded. Do your yearly coolant system maintenance, and there wont be any problems. You dont need to worry about voltages, just keep up with the maintenance.

 

Thanks for the information.
I will get a coolant flush ASAP. I know I need one. Havnt had one for like 3 year now. I have only put like 12k on the dial though. Fluid looks brand new but obviously that means nothing anymore.