Mounting radiators - electrolysis(?) concerns

[MWP]

So the answer to the OP is "insulate it".

Correct.
Which funnily enough is against all the "ground it better" advice given above.
+rep for you.

[Norbie]

The "ground it better" advice referred to the engine, not the radiator.

I find it strange that radiators aren't insulated from the factory though?

[Mos]

I find it strange that radiators aren't insulated from the factory though?

Oh but they are! I might not have been paying full attention but I'm pretty sure most toyotas since the early 80s had an insulated radiator - the sprinter certainly did, as did anything I've owned after it.

Mos.

[30psi 4agte]

So the answer to the OP is "insulate it".

Mos.

Im not trying to prove anyone right or wrong here as to be honest i thought i was right in saying having good grounds is a KEY measure to prevent electrolysis,along with correct coolant etc Which is what i was taught in trade school anyhow.

So from the varied opinions here i decided to find out a bit more for myself to see if i was right or wrong + learn some more and let my mind rest

Now we all know electricity will always take / find the easiest way to ground and acording to this article "without a good grounded radiator the coolant will try to eat its way through the radiator to get to ground.

I have sifted through this aricle and copied the major points and posted this here in the forum for all to read and hi-lighted the parts of interest .

I will post the link to the whole article too but i thought id actually put most of it straight on this thread so it will actually be read. ...... I think its worthy.

So here ya go.




Failing to discover and replace one torn ground wire can precipitate a very serious radiator and/or heater degradation problem for unsuspecting customers.

You may be familiar with the term “electrolysis” as it relates to the destruction of hair roots with an electric current. In the automotive world, electrolysis can cause hair pulling by service technicians who are unable to diagnose the root problem.

Although electrolysis is a somewhat complex electromechanical reaction involving anodes, cathodes and Faraday’s laws, you don’t need to make a run for the chemistry textbooks or the Internet. In simple terms, electrolysis in a radiator or heater is the localized degradation of the metal caused by excess electrical current flowing through the cooling system’s liquid coolant or metal transmission lines in search of an electrical ground. But what happens when there is no ground to be found, or an ungrounded electrical device in the vehicle creates excess electrical current?

Electrical current can be introduced into the cooling system in many ways, but some common causes are loss of ground due to mechanical damage or corrosion, or a frayed electrical wire coming in contact with the radiator. Any vehicle with accessories (such as driving lights) using the radiator as a ground is begging for an electrolysis problem. For body shop personnel, failing to see or detect a ripped ground wire or forgetting to replace one or more ground wires can cause electrolysis that won’t show up until months after your customer has left your shop with a repaired vehicle. Proper grounding is the key to avoiding the occurrence of electrolysis and, should it occur, grounding can be the key to diagnosing the root cause

Grounding more important than ever
No doubt, the installation of additional electrical systems, components, microprocessors, sensors, electric motors, electronic convenience items and related circuitry has placed an added burden on the automotive service industry in general and body shops specifically. Although microprocessors are capable of providing feedback through self-diagnostics, they have limitations. That means service technicians need various scan tools and electronic meters to receive the two-way communication that today’s electronic components provide. Having the tools is one thing. Understanding the concepts and interpreting the readings are critical to successful diagnostics.

In spite of the electronic revolution sweeping the industry, one basic tenant remains unchanged. To complete the flow of electricity, the negative circuitry emanating from the battery must be properly grounded. Almost without exception, the frame and/or body sheet metal serve as the primary grounding device for the electrical system. If properly connected, it is in fact an extension of the battery negative connection. Although the body is typically isolated from the chassis by non-conductive, cushioned insulators, the many supplemental ground wires connected to each vehicle body are connected back to the chassis and the battery by one or more body-to-frame jumper wires.

While the vehicles of yesteryear may have had just a few ground wires, it is quite common to have between 10 and 20 chassis-ground connections sharing the load today. Each must be functioning properly to complete the circuit and route the flow of electricity back to the battery. Any broken, loose or corroded connections are almost sure to cause a malfunction and/or alter the flow of electricity. Because it takes the path of least resistance, electrical current will stray from its intended route and create a return flow by looking elsewhere.


Be suspicious of ground wires
Damage to ground wires is almost inevitable, even during a moderate collision causing $3,000 to $7,000 in damage. During the repair process, be sure to check your collision repair reference to make sure you know the location and connection points for all ground wires. When they are securely connected, the electrical path is well defined. On the other hand, any breach will cause the electricity to find the shortest, easiest, quickest path of least resistance. Particularly for electrical components or circuitry in close proximity to the radiator or heater—that path can involve the coolant itself.

If you have the occasion to check for electrolysis, use a digital voltmeter set for 12 volts. Attach one test lead to the negative battery post and insert the other test lead into the radiator’s coolant, making sure the lead does not touch the filler neck or the core. Initially, you may see a surface charge that could be 0.7 volts or higher. It could take up to two minutes for this surface charge to dissipate. Only then will you be able to obtain an accurate reading. A voltage reading of 0.3 or higher indicates that stray current is finding its path to ground through the cooling system.

Cooling fans and A/C-heater fans are logical sources to check and eliminate early in your diagnostic process. Then check any non-factory accessories that have been added. Next, you can turn the ignition to the run position while turning various accessories on and off. When the meter’s voltage jumps, you’ve found the circuit with a bad ground. A small amount of electricity normally flows through a vehicle’s cooling system. In a properly grounded system, this small charge (less than 0.3V) is constantly discharged and no harm is done.

Serious problems with stray-current electrolysis can occur when the cooling system is not grounded or when an ungrounded electrical device is part of the vehicle’s operating system. The cooling system then becomes a warehouse for this stray electricity, and the coolant turns into an electrolyte. This charged coolant is constantly searching for a ground or a way out of the system. When it finds a material it can attack (the path of least resistance), the coolant goes to work “eating through” that material radiator and/or heater causing damage such as the following:

Solder-joint destruction
Aluminum corrosion and flake formation that clogs the system
Cast-iron corrosion that causes rust to contaminate the cooling system
Stray current also can be a problem with new, straight-from-the-factory vehicles. Back in 1986, Ford recalled approximately 19,400 vehicles to find a misrouted battery cable that could send a low-grade electrical current through the radiator, setting up an electrolytic action that could promptly ruin the radiator.

Frequently, by the time your customer realizes electrolysis is taking place, the radiator or heater damage is already done. Unlike a radio that frequently hums when a short exists or a resistor malfunctions, the cooling system does not emit an audible sound. To make sure that electrolysis doesn’t start in your shop, let your technicians know the importance of reconnecting all ground wires

http://www.abrn.com/abrn/article/art....jsp?id=154932

[Norbie]

Oh but they are! I might not have been paying full attention but I'm pretty sure most toyotas since the early 80s had an insulated radiator - the sprinter certainly did, as did anything I've owned after it.

Well I've owned 3 MA61's and all of them had the all-metal radiator bolted directly to the radiator support, nothing resembling insulation there! I think most Toyotas switched to plastic end-tanks after that so I guess they were insulated by default.

[oldcorollas]

were the MA61 radiators copper/brass (or whatever ) or alloy?
all the alloy ones i have seen have had plastic tanks and are insulated...

i spose i should point out there is a difference between galvanic corrosion and electrolysis..
galvanic corrosion happens when dissimilar metals are connected.. usually in presence of water, with oxygen as well. not much you can do about this except to reduce oxygen content etc.. this is how sacraficial anodes work..
but the cylinder heads are alloy anyway...

electrolysis doesn't need to be different metals.. just one has to be anode and the other cathode, but there has to be an applied voltage.
perhaps if you use earth leads between radiator and engine block, then you are doing the best you can to minimise it.. since the radiator is not even connected to battery.. and the corrosion circuit would be with the engine block...

if an alloy cylinder head can survive, i dunno why the radiators are such a problem....

[Mos]

Well I've owned 3 MA61's and all of them had the all-metal radiator bolted directly to the radiator support, nothing resembling insulation there! I think most Toyotas switched to plastic end-tanks after that so I guess they were insulated by default.

Yeah, I'm aware MA61s are directly attached, but they're old
Plastic tanks, both top and bottom mounts are rubber mounted, so not the plastic tank on its own provides the insulation.

Mos.

[Pube]

My radiator is an excel X2 unit that has plastic end tanks and instulated mounts. My main concern is my water to air heat exchanger. The stock 1ggte water to air intercooler is rubber mounted and is alloy. My heat exchanger is alloy also but is solid mounted to the body of the car. Im just worried that I should have rubber mounted the heat exchanger even though PWR did not make the brackets to suit rubber mounting, rather to solid mount it. Since the intercooler is actually insulated from the engine am I safe?

[oldcorollas]

oh, in that case... run a cable between the IC and the exchanger. that should stop electrolysis.
the water won't be that hot (or better not be!) so any corrosion should be much slower...
if you feel nifty, get some of those rubber washer things designed for insulating stuff (electronics adn the like) and use them..

[Mos]

Given that there is no applied voltage between the radiator and block, I'm of the firm belief that electrolysis is not the phenomenon occuring here.
My position, therefore, remains that the radiator should not be grounded.

I'd also like to add that the article quoted is flawed for reason that I cbf getting into at the moment.



Mos.

[oldcorollas]

ok, after some discussion and searching...


if you have similar metals.. ie Alloy IC and alloy heat exchanger, then you can connect them by cable to stop eletrolysis, sicne galvanic corrosion will probably not occur (unless they are significantly different alloys)


if you have dissimilar metals, then galvanic corrosion is a problem, and you should NOT connect them. this goes for both brass/copper and alloy radiators....
if you don't connect, maybe there is electrolysis, but that should only occur if they are connected anyway (since you haev to apply a voltage)..

so if you electrically isolate the radiator, then neither galvanic corrosion or electrolysis can occur.

this concept of "stray currents" i find a bit odd..... it is saying that the big fat earth wires have more resistance (or not ,much less) than water with salt in it.. which is a bit strange....

anyway...


since copper/brass radiators are almost always connected to the body.. then perhaps that is why iron blocks almost always corrode... the alloy head will also corrode due to galvanic corrosion, but perhaps it passivates... whereas iron does not.

anyone had an iron blockcorrode with an alloy radiator and alloy head?

[sideshow]

who is goin to read all that

just ring pwr they will tell u everything u need to know

hehehe

[rob1]

lol. had the same problem with a vs commodore. new radiator lasted not even a month before leak came in same place. between .5 and .7 v in the coolant. tried earth straps to motor, (extra), didn't fix it. changed plug leads and fixd it! go figure.

[oldcorollas]

who is goin to read all that

just ring pwr they will tell u everything u need to know

hehehe

good to see you're a thinking man

[Howieau]

Resurrecting an old thread here.

I am currently dealing with a similar problem. When I pulled my engine apart I found the coolant galleries on my head had corroded due to electrolysis.



Now that my engine is back together I have used a multimeter to check the voltage in the coolant and it was up to .70 volts. I put ground wires from gearbox to chassis, block to chassis and head to chassis. Also changed over to brand new coolant. Made sure all contacts areas of the wires were free of paint or anything that could interrupt the flow of electricity and also used some rubber to further insulate my radiator from the chassis. Now it fluctuates between 0.15 and 0.18 volts. Is it true, as aforementioned in the quoted article, that anything below 0.3 volts is nothing to worry about?

I just don't want my head being eaten away anymore. Id like the thing to remain intact for as long as possible!

Thanks in advance