Why do I keep destroying aluminum radiators?!?
 

My truck is a 1972 C20 Suburban with an iron block 6.0L LS swap. I've been running Entropy's aluminum, LS swap radiator since I built the truck 10 years ago. My third radiator, which is just under 2 years old, started leaking from the core again today.....I'm assuming due to electrolysis and the aluminum welds failing.

I'm at a loss at this point. The radiator sits on rubber isolators but it has a grounding strap from the aluminum body to the frame of the truck, as well as a sacrificial zinc anode that is grounded directly to the battery per Entropy's instructions. The motor is grounded to the frame with a 1 inch braided grounding strap and the battery is grounded to the engine block with a 0 AWG cable.

Any thoughts or insight would be greatly appreciated. I've never had a problem like this before running an aluminum radiator.

Thanks!

Re: Why do I keep destroying aluminum radiators?!?
 

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Can you see the corrosion or just taking for granted that's what it is?

What kind of body mounts are you using, Rubber or Poly? Could it be a vibration issue maybe?

Just throwing out an idea. I have never used an aluminum radiator so I have no actual experience.

LockDoc

Re: Why do I keep destroying aluminum radiators?!?
 

I havent looked at this one closely enough as I just realized it was leaking after work today. The last one I pulled out definitely had powdery white corrosion all over it.

I doubt its a vibration issue as I'm using the factory rubber insulators in the factory big block radiator mounts.

Re: Why do I keep destroying aluminum radiators?!?
 

I have an Engineered Cooling Products ECP all aluminum welded radiator and there were no instructions for grounding it, and I have it in the rubber mounts with no ground wire. I asked them in an email if sacrificial zinc anodes are really a thing and were recommended, and they said yes that is a thing to consider and they recommended getting one but did not have one to sell me. I got one from Amazon that screwed into the drain plug outlet in place of the petcock valve and ran it for a couple of years. It did not connect via a wire to anything. I removed it to see if any of it had been corroded away, and it had no deterioration after a couple of years, so I removed it and put the petcock valve back on. Perhaps my truck in the configuration I have does not eat the aluminum radiator. The radiator is about 7 years old and has a lifetime warranty. I have wondered if the particular sacrificial zinc anode I bought is real or fake junk offered by an unscrupulous maker, and have wondered about grounding radiators or anodes.

Is Entropy sending you radiators for you to swap out, or repairing your radiator under warranty, or are you buying replacement radiators? Is there any deterioration of your sacrificial anode?

Re: Why do I keep destroying aluminum radiators?!?
 

Unfortunately, I've been replacing them at my expense over the last decade. Their warranty process is painful and cumbersome, though at this point, I wish I had made the effort.

For what it's worth, I just dropped the positive probe from my multi-meter into the coolant in the reservoir, and grounded the other probe to the battery. I'm showing .2 Volts. I dont know if thats enough stray voltage to eat the aluminum welds over time, but it's definitely there, and I have no idea how to chase it.

I havent pulled the zinc anode yet as the mosquitos were getting unbearable out in the driveway. Ill take a look at it tomorrow.

Re: Why do I keep destroying aluminum radiators?!?
 

I wouldn't have any ideas on chasing that with an LS engine. On a first generation stock engine there's really no electric going to the engine that could leak except the coil and spark plugs. But I would start by removing the ground wire on the radiator and anode and see if you can get that same .2 V reading, and check out that sacrificial anode condition. I think if it isn't corroding, it's not doing its job and you might as well just not have it. What kind of coolant do you have, is it plain green stuff, ethylene glycol with corrosion inhibitors? Or something else? Do you change it every year or two? The corrosion inhibitors supposedly wear out causing the need to replace it.

Re: Why do I keep destroying aluminum radiators?!?
 

I'm running the standard GM Dexcool that comes from the factory in all LS motors. It was replaced less than 24 months ago. I'll pull the wires and do some more investigating tomorrow.

Thanks for the help!

Re: Why do I keep destroying aluminum radiators?!?
 

I'm thinking it's likely Dexcool destroying it. https://www.consumeraffairs.com/news...m_dexcool.html

Re: Why do I keep destroying aluminum radiators?!?
 

This issue you are having reminds me of a Cadillac that my Momma had.

Look up Northstar Coolant issues.

We had to add some type of plant base pellets.

Hope this helps.

Re: Why do I keep destroying aluminum radiators?!?
 

Oh man, I had no idea! Fortunately, the leak is more of a sweating than a full blown leak at the moment so Ill drain and fill with distilled water, and do that every few days for the next month or so to really flush the system, then order a new radiator and go with the green stuff.

Also going to call Entropy tomorrow and see what they say about normal expected voltage readings across the radiator. I've ready anything above .1 volts is cause for concern but other also said above .3 volts or above .5 volts. So who knows at this point.

Re: Why do I keep destroying aluminum radiators?!?
 

Did some more investigating tonight. With the probe in the coolant, the voltage reading is anywhere between .2 and .25 with the ground probe placed on the battery, frame, or engine block.

I did the same test on my 2002 Toyota 4Runner and my wife's 2016 4Runner and got .18 volts in both of those.

So if a minute amount of voltage through the coolant is "normal", is it really the Dexcool that keeps destroying made in the USA radiators? Most of the guys over on the protouring forum with LS swaps and aluminum radiators are running Dexcool with no issues.

Re: Why do I keep destroying aluminum radiators?!?
 

I don't know. Dexcool gets a bad rap from some and others do not have a problem. I've not heard any bad news about green ethylene glycol coolants, so I perceive them as lower risk. I could be mistaken.

Re: Why do I keep destroying aluminum radiators?!?
 

I agree that the green coolants are low risk in a new system, or a system already running it, but dexcool and ethylene glycol do not mix well and ensuring you flush all of the dexcool is a challenge.

That being said, if I knew that was the answer, I would absolutely go for it. What I dont want to do is throw another radiator at this thing, swap the coolant, and just hope for the best. Id really like to find a definitive cause...or at least someone who can tell me one way or another if the .2ish volts across the coolant are what is causing the radiator to deteriorate so fast.

Re: Why do I keep destroying aluminum radiators?!?
 

Does your zinc anode show any degradation? If not as previously stated it's not doing its job.

Use the best ohm meter (Old Simpson 260's are good for this) you can find and check the resistance between the anode and the radiator. It needs to be zero. Electrolysis is the flow of electrons if the anode is electrically isolated no electron flow will occur and the radiator will not connected to the sacrificial zinc alloy and as a result may be sacrificed.

It is tough to put an exact voltage that may be too much, as coolant flowing over dissimilar metals contributes to the erosion of the weakest metal. That part of the erosion process is difficult to measure or diagnose. So what one vehicle is okay with, the next one will fail with that same voltage

Coolants have corrosion inhibitors in their formulas and are meant to prevent electrolysis between dissimilar metals. They however may not prevent electrolysis between every conceivable combination of alloys. Doing an inspection for any non GM components that are in the coolant would be a good start. Like temperature senders. If you have a real electrolysis problem your coolant protection can be used up in 20 hours or less. In the commercial marine world we do periodic testing of the coolant to ensure protection.

On the electrical side electrolysis is compounded by stray electrical current flowing through the coolant. Checking the voltage in the coolant is a start. Did you do it with engine running and shut off? How about not running with the key on?

Try using a multimeter and see if any of the sensors are partially grounded. On an LS this might be easier if the harness was unplugged from the ECM and you tested each wire to ground with the battery leads disconnected.

Electricity takes the path of least resistance and it may be that an something not related to the cooling system is where the current is coming from. Also make sure none of your engine ground leads are attached to a bolt that is exposed to coolant. That path of least resistance may be using the coolant to get back to the battery.

From my experience on tugboats I would not run a lead to battery from the anode as that doesn't find the source of the electrolysis it merely is an attempt to mask the symptom. The result of that may be the electrolysis is still present but now attacking a different part.

I'm sure I've forgotten lots but my battery is dying, so it post or loose it. :lol:

Re: Why do I keep destroying aluminum radiators?!?
 

It was my thought that the radiator was to be isolated from the metal frame not grounded.
Thoughts?

Re: Why do I keep destroying aluminum radiators?!?
 

I can't speak with confidence on that part other than to mention that an automatic transmission with factory steel lines would provide an electrical path from the radiator to the transmission. So it would seem to be okay to have the radiator grounded.

Re: Why do I keep destroying aluminum radiators?!?
 

Good point

Re: Why do I keep destroying aluminum radiators?!?
 

I assume you have excellent ground between the engine block, the frame, and the body? Poor ground there makes the radiator the good ground.

Re: Why do I keep destroying aluminum radiators?!?
 

+1
Even if rad is isolated with rubber mounts. Many do not understand, if using tap or distilled water as soon as it is put into the system it is contaminated and will flow electricity.

Re: Why do I keep destroying aluminum radiators?!?
 

The factory had all kinds of problems with Dex Cool and aluminum parts...mostly with the intake manifold and the heater core fitting in the back of the head. Just rots it out. If I'm working on a new vehicle that has dex cool I'll flush it the best I can and go to the glycol green

Re: Why do I keep destroying aluminum radiators?!?
 

the sacrificial zinc in the radiator looked brand new after 2 years, so I would guess electrolysis is not the culprit here.

One of the guys on the ProTouring forum pointed out that the Entropy radiators have the top plate welded on, thus tying the end tanks, cap, and core together. Because the core will expand at a different rate than the solid top cap with heat, he suggested you can end up braking the welds in the core. It does make sense as the core was leaking from both top corners.

I went ahead and ordered a cheap, chinese aluminum radiator that doesnt have a top plate. We'll see how it holds up.

Re: Why do I keep destroying aluminum radiators?!?
 

There is so much controversy over radiators in the market, and on this forum, in terms of price/quality/materials/warranty/ etc., it's astounding! From my research, there are inexpensive, moderately priced, and expensive radiators, but quality doesn't always match the price. After spending a lot of money on your entropy, only to be disappointed, I think you went in the logical direction buying an inexpensive replacement. It should last a good long time and if it leaks you can replace it with another one, guilt-free, since it probably cost half of a moderately priced USA made radiator. Unfortunately, we live in a world where replacing is often cheaper than repairing. I went through the same debate and decided to purchase a radiator from Ron Davis. I thought about it very long and hard given the price was what I considered to be exorbitant. I pray the quality matches the price (haven't installed it yet). Good luck to all!

Re: Why do I keep destroying aluminum radiators?!?
 

If you are mixing your coolant, I would guess it could be your water, if you use a softener for it, if you are, maybe only purchase and use the 50/50 coolant mix for the new radiator.

Re: Why do I keep destroying aluminum radiators?!?
 

I've only ever used the 50/50 premixed GM Dexcool.

Re: Why do I keep destroying aluminum radiators?!?
 

I did notice....I have a pretty pricey DeWitts aluminum radiator and fan combo in my '64 Corvette. It does not have a top plate on it....just the core and the end tanks so there may be something to the theory that the welded top plate expansion can cause the core welds to crack first. We'll see.....