Zinc anode for radiator

J

JimNNN

Well-known member
My Thunderbird and '61 Mercury both have Aluminum radiators in otherwise stock applications. I'm thinking about maybe putting one in my Ranch Wagon at some point, too. Recently, however, my neighbor with a '36 sedan street rod with a sbc said he didn't want an aluminum radiator in his car because of an incompatible metals problem.

After the problems I've had with the alum. dist. housing in my Y-block, I can appreciate that sentiment, but I never thought more about his comment. Then I just saw this product from Mac's...a sacrificial zinc anode to keep aluminum from deteriorating and "reduces the harmful effects of electrolysis". I was surprised I'd never heard of these.

Do I really need these? When I ordered my '61 Radiator from Wizard Cooling a couple of years ago, they never mentioned the need for one, and I talked to them at length about putting an aluminum radiator in my car. Good quality radiator, too. I thought I'd ask you guys about this.







https://www.macsautoparts.com/alumi...a-made-sacrificial-zinc-anode-32-23773-1.html
 
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There are a few problems that can occur. Aluminum is softer than other materials and can also be damaged by stray voltage. It's caused by inadequate grounding, this is a different problem than electrolysis. Not covered by warranty either. Loose, missing, or corroded ground straps and general rust & corrosion are pretty common in older collector cars. Also a similar problem electrically are thick layers of paint in restored cars and trucks. I'd be willing to bet what some people are calling "electrolysis" is at least in some cases actually caused by stray voltage.
 
Dielectric action between dissimilar metals is a fact of physics. I won't go into the how's and why's of what happens other than mixing of steel and aluminum will promote deterioration/corrosion. You should always have a barrier coating or membrane between dissimilar metals (standard practice in the construction industry) to prevent contact between the two. In the case of a cooling system, though, the aluminum radiator doesn't come into direct contact with another metal, but as I understand it a minute electric current is created by the passage of ions from steel to aluminum through the coolant as a electrolyte (or is it vise-versa - I haven't committed that to memory) and will produce corrosion over time. A sacrificial anode would be highly recommended in my opinion to reduce this corrosion and control the process - you'll have to remember to replace the anode over time. You can get reproduction radiator caps with the anode suspended from it, or look in boat supply house catalogs/websites to see what they offer. Likewise, running aluminum water pumps, intake manifolds or cylinder heads with a steel block should also dictate installing a sacrificial anode to reduce the detrimental effects of dielectric action.

Whenever someone asks me about installing an aluminum radiator in their T-bird, I always recommend they install a sacrificial anode and advise them about the different properties between aluminum and brass, which historically isn't as prone to this issue like aluminum is. After all, it's what the factory engineers had used in their designs for many decades before the advent of plastic radiator tanks and aluminum cores, aluminum engine blocks/components, etc.

This reminds me that I need to get one of those anode-element radiator caps for the '63 T-bird I have with a "M"-series tripower aluminum intake manifold.
 
Then I just saw this product from Mac's...a sacrificial zinc anode to keep aluminum from deteriorating and "reduces the harmful effects of electrolysis". I was surprised I'd never heard of these.

Do I really need these?
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Same method used in your water heater, sacrificial anode.

Whenever you introduce aluminum to an older iron engine, it is going to present problems. How many have installed an aluminum intake and never gave it another thought until corrosion ate the coolant passages in the intake?

There are special blend coolants for a mixed system and test strips (acidity) you use on a regular basis. That and required regular flush/fresh coolant service.

NOTE -

All the above is IMO and your experiences, results and mileage may vary ... :D​
 
Thanks for the great education, guys. I'll buy some of the anodes. I doubt there's been any big deterioration in my Mercury radiator in the two years I've had it on the car - don't drive it much - but I have no idea how long the aluminum radiator has been in my T-Bird. I don't see any indication of problems on either car as of now, but maybe the T-Bird has had a sacrificial zinc anode in it before. Or maybe not, who knows.



So on the FE engines in my T-Bird and Merc...would the anode go in the expansion tank?? I don't know where the best location is. And the radiator tank of my Y-block, should I go that route?


I'll search for some acidity strips and the special anti-freeze, too.
 
JimNNN said:
I doubt there's been any big deterioration in my Mercury radiator in the two years I've had it on the car - don't drive it much - but I have no idea how long the aluminum radiator has been in my T-Bird. I don't see any indication of problems on either car as of now, but maybe the T-Bird has had a sacrificial zinc anode in it before. Or maybe not, who knows.

So on the FE engines in my T-Bird and Merc...would the anode go in the expansion tank?? I don't know where the best location is. And the radiator tank of my Y-block, should I go that route?

I'll search for some acidity strips and the special anti-freeze, too.
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If you have been using green coolant for the past two years, you want to stick it.

The best position (IMO) ... :D ...

... would be at the radiator pet ****. The rod needs to be completely submerged in the coolant. Unless you have a coolant recovery system on the car, it will not remain submerged constantly when included in the cap..

READ HERE - https://www.flex-a-lite.com/radiator-anode.html
 
I believe dissimilar metals have to touch to create a reaction. With the exception of the rad cap other metals are isolated from the rad. Correct or no?
 
L5wolvesf said:
I believe dissimilar metals have to touch to create a reaction. With the exception of the rad cap other metals are isolated from the rad. Correct or no?
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The coolant does the actual 'touching' in a cooling system.

And CRANKSTER brought up a good point also. FORD issued a TSB not recently but suggested adding a ground strap to an alum heater core as a means of getting around heater core failure.

It has to have the correct coolant as do modern cars.
 
​

As for deciding when to change your antifreeze, don't go by miles or you WILL certainly have seal and mechanical failures. One interesting spec I found is to use a multi-meter.

You put your negative probe to the negative post on your battery. You then place the positive probe in the neck of your radiator, making sure that the positive probe touches nothing but the antifreeze. Make sure the coolant is warm but not HOT (this is for SAFETY reasons as well as accuracy of your readings. Always be careful when opening the radiator cap on a warm engine). Your readings (regardless of negative symbol on readout) should be:

0.2 V to 0.5 V - antifreeze is still good
0.5 V to 0.7 V - antifreeze is borderline
0.7 V or greater - antifreeze is unacceptable.

You can also use test strips (available at a quality auto parts store for $5 or less), they work on both green and red types too. But if you already have a multi-meter, why go buy test strips? The multi-meter is the more technically accurate method anyway.

As for sludging and early parts failure, it is imperative that you keep the antifreeze topped off or the low fluid level will cause sludging. There is a GM Technical Service Bulletin (TSB) on this matter.
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SOURCE - https://www.getahelmet.com/jeeps/maint/dexcool/

I am not endorsing DEXCOOL but this guy pretty well nails the procedure(s). Read it in it's entirety.
 
The Champion radiators that are now popular will definitely not win any concours judging competitions but the construction is reasonable for the money, no epoxy to be found, and the welds are actually pretty good. They recommend prominently (with a sticker on the box no less) "Use Distilled Water Only mixed 50/50 with Coolant" etc.

The "antifreeze" part of engine coolant never wears out, it never loses freeze protection is my understanding, but the corrosion inhibitors included get used up over time, that's mainly why it needs to be periodically flushed out and renewed with a fresh 50/50 mix of water and coolant.

The "stray voltage" (And static electricity) can cause some really strange problems that are expensive, and hard to diagnose. One of my favorites I read about is a problem discovered by fleet owners where plastic tarps used to cover loads on flatbeds in particular built up a large static charge when running long hauls on the dry intermountain West highways, the static would eventually travel from the driveshaft into the transmission and "found a ground" discharge through a particular bearing, eventually leading to transmission failure.
 
Back in one of my previous incarnations I was a field rep for Standard Ignition. At that time the local power company, HL&P (Houston Lighting & Power, aka., Houston Looting & Pillaging) was using big gas powered Ford trucks with BIG 2 way radios. They were using Standard's Blue Streak (heavy duty) version of Ford's ignition module to replace the OEM modules when they gave up the ghost. HL&P soon began reporting that if the drivers keyed the mike for their radio it killed the engine. Somehow the transmitters could set a RFI that could confuse the module enough to kill the engine. Standard came up with an internal shield for the modules that deflected the RFI. Problem solved but it took a bit of head scratching.
 
Crankster said:
The "stray voltage" (And static electricity) can cause some really strange problems that are expensive, and hard to diagnose. One of my favorites I read about is a problem discovered by fleet owners where plastic tarps used to cover loads on flatbeds in particular built up a large static charge when running long hauls on the dry intermountain West highways, the static would eventually travel from the driveshaft into the transmission and "found a ground" discharge through a particular bearing, eventually leading to transmission failure.
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This seems to verify my theory that electricity isn't actually a physical phenomenon, but an evil force that dislikes most of us. Better that we sacrifice a zinc anode to it every now and then than one of our neighbors in a creepy ceremony.
 
Jerold Ebke said:
Is a zinc anode useful in an original copper radiator?
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No need as early engines did not use ALUM components generally.

Now if you have added an ALUM intake, cyl heads and/or timing cover, you might want to consider it. The main reason for it's use with an ALUM RAD is the material is so thin. A little corrosion goes a long ways there.

Modern engines use specialty coolants to control it (along with proper maintenance).
 
What happens with dissimilar metal corrosion, or galvanic corrosion, the two different elements in the presence of an electrolyte (engine coolant) forms a weak electric current. That's how batteries are made, in fact. Take any two elements far apart on the reactivity scale. Carbon and Zinc, for example, were used in flashlight cells because they were inexpensive. Brass and Steel are pretty close on the reactivity scale, but Aluminium and Steel is far enough apart to cause trouble. I think sailing ships have these big zinc anodes so the hull doesn't corrode away, or maybe the props?
 
Ships do have anodes on their hulls. The anodes are usually replaced about every 3 years or so when the ship goes to dry dock for routine inspection/maintenance. The props are made of bronze alloy and aren't much subject to electrolysis. They are subject to cavitation damage, making them rough and less efficient, so they get smoothed and polished during dry dock. Lots of videos on YouTube if anyone is interested.
 
dmsfrr said:
This also helps explain why distributor housings get stuck in the block.
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My distributor shaft housing is still stuck in my Y Block...even after a couple of months of effort and six cans of penetrating oil. Frustrating because the timing is 3 degrees off and I can't change it...but I won't get off on that tangent. There are a couple of long threads already devoted to that.



KULTULZ said:

That neighbor possibly having a CHEBY parked in the driveway?
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LOL! Or better yet, a Nissan.
 
I have an aluminum radiator in my Ford, also aluminum heads and intake manifold. I put a ground wire on the radiator to the support wall. I bought a sacrificial anode and cap, believe from Be Cool products.

It was in for 4 years, I figured it may be shot so I picked up some marine anodes on eBay, real cheap. I took the old one out and it was perfect. I put in a new one anyway since I had 5 of them.
 
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