This is a quote from a recent post on talkabout re: 1995 4Runner :

"The v6 is also known to eat radiators. I'm on my 4th. Problem is with
electrolysis and can be helped by insuring the radiator and block are
grounded to each other. The first one left me just after the warranty died."

So like a rote dummy, despite my being incredulous, since the radiator is firmly attached at multiple points, I run out and check my resistance back to the neg. terminal on the battery. I get an average 200milliohms. Insignificant. Same with the block, of course.

Hard to ignore someone that makes such a specific claim. I repeat it here just in case someone has had such a problem. Did several searches with no results on YotaTech.

So my conclusion is, while electrolysis may be caused by other things, such as a wrong choice in coolant, or running pure water, it is unlikely to be caused by lack of grounding of the radiator.

Anyone else with comments?

 

Well you can eliminate electrolsis using certain water conditioners, or Toyota Brand Red Antifreeze or even GM's DexCool.

But electrolosis didn't eat up my radiator, it ate away at my block and the corrision caused the head to warp and took out my headgasket.

 

I have gone through 3 radiators - however I do have 230,000 mile on the truck. The first on started to develop pin holes where the upper hose dumps into it - this I attributed to simple etching of the brass over time. The next next radiator started to seep at the top seam - I think this is from a bad soder as it was only a couple of years later & not a lot of miles. None of mine have failed due to the above quote. However I have seen a few others that have failed in the exact same spot of my first one with the same milage as mine when it failed - I think it is due to the good pressure that the water pump puts out & etching more than anything else.

 

i think most of the time it's probably just stress on the radiator -- they are rather fragile and it doesn't take much to bust the brazed edges and hose fittings.

 

Mine fell apart (no kidding) and it was the original one. Oh it never leaked a drop.

 

Mike kind of fell apart and leaked a little at about 130K, but that was from major off-road bashing, not electrolysis.

Seems like a little bit of a strange claim, since the radiator is grounded by being mounted to the body, and the engine HAS to be grounded for it to work...

 

I think electrolysis is caused by ionized water creating mild current in across different metals and I think heat accelerates it. Pure water doesnt conduct electricity, metal particals in water do that, so maybe replacing radiator fluild with deionized, distilled water more frequently would help solve the radiator problem? (of course using radiator fluid with the water)

 

trythis brings up a great point........Everybody SHOULD be using distilled water but I know that's not the case. I always wondered how they expext anybody to use DW in the entire radiator system......the only way to flush the system is hook the garden hose up and let it rip.....but garden water is full of minerals. Catch 22.

rdharper---with you being on the coast, I would expect some salt in the air....so maybe there is some electrolysis going on.....maybe you can test that theory by properly grounding the radiator directly to the neg post. Do this by soldering a wire directly to the top of the radiator near the fill neck. Use regular 60/40 solder with ACID core. Flux core will not promote a good flow. Use a solid copper wire(not stranded).....a piece of house electrical wire....whatever they call that white rubber insulated 3 conductor stuff.

oh ya, do the distilled water too.

 

What you're talking about is not electrolysis, it's galvanic corrosion.

In the galvanic series, however, Aluminum, Iron, and Mild Steel are very close. This would mean they are not very prone to corrode each other. So if your radiator and engine are made of these, it won't cause galvanic corrosion. Now if something around there is made out of stainless steel, that could be a problem... What's the Toyota radiator made out of? And while I'm at it, doesn't antifeeze have additives to prevent this kind of thing?

Galvanic corrosion is a big thing in engineering (especially mechanical), I find it hard to believe that Toyota engineers would have overlooked this, unless they purposely made it so that the radiator corrodes instead of your engine block, which is possible...

 

Then what is electrolysis?

 

Electrolysis is when there is a induced voltage accross two electrodes in water, and the electrodes break apart the water, developing bubbles of Hydrogen and Oxygen on each one separately. This makes one of the electrodes corrode. So you have two wires in water, and you plug positive terminal of a battery to one end, and the negative to the other. The problem is that if both the radiator and the engine block are grounded, they are at the same voltage and cannot be causing electrolysis.

Electrolysis on Wikipedia

Galvanic corrosion occurs when two dissimilar metals are placed in contact with each other in the presence of an electrolyte, such as salt water, resulting in the unintentional formation of a galvanic cell and concomitant chemical reaction of the metals involved.

Galvanic Corrosion on Wikipedia

So if you have water with a lot of ions in it, like salt water (or possibly tap water) and you put the two different pieces of metal in there it turns into a battery, one corrodes while the other actually gains mass. This only happens with certain metals based on their placement in the "Galvanic Series," which rates how "active" or "passive" they are. There is a small voltage difference between certain metal types that is created by this corrosion process. This could possibly be happening in an engine if there are two metals that are very dissimilar in the galvanic series... AND there are lots of free ions in the radiator water. I think that antifreeze has additives that tend to prevent this though.

Galvanic corrosion tends to be a very big problem on boats, because salt water is an excellent conductor. Depending on what kind of metals are underwater with your boat, your hull could corrode!

 

Gotta love that Wikipedia.. only place where you can get acronyms, dictionary, encyclopedia, including tech and Scientific terms... for free no less.

Nice posts Brian!

 

Didn't I see in the FSM something about testing the voltage in the anti-freeze to see if it good or bad?

 

I don't know, maybe measuring the resistance of the fluid to try and judge how many free ions it has floating around in it...

 

The only test I'm aware of for anti-freeze is to check the relative density between water/solution for whatever protection your looking for (-40 Deg F?). Past 50% is counter-productive...

 

I did some quick searching and here is one article i found ANti-freeze