Aluminum radiator upgrade

[ROCK HARVEY]

I’m interested in this because my truck came with a champion aluminum radiator. No idea how long it’s been in the truck. I also have access to a truck being parted out that still has the stock radiator, and now I’m thinking of grabbing it.

 

[ISPKI]

I dissagree, ☺ . 6061 aluminum,
https://en.m.wikipedia.org/wiki/6061_aluminium_alloy

Not sure what that link is supposed to show but copper carries a thermal coefficient of 389 vs aluminum at 239. Silver is the only element that is superior to copper at over 400. Ratios are similar for electrical conductivity, 110 copper alloy comes in around 85-90% of silver (silver being the benchmark for conductivity) Aluminum, last I checked is about 50% or 60% that of silver. Hence why aluminum cables need to be made to larger gauge sizes to handle the same load as copper.

The ONLY reason why aluminum radiators can outperform a copper alloy radiator is the joints. Copper alloy radiators are soldered or brazed and those solder joints, depending on their quality and age, can inhibit thermal and electrical transfer. Aluminum on the other hand is usually welded directly. Now, if someone were to build a copper radiator rather than a copper and brass radiator, the copper radiator could be welded which would make it many times superior to any aluminum radiator.

The other issue with aluminum is that it has terrible fatigue resistance. Vibrations and flexing of the material can quickly damage, gall, and crack 6061 aluminum whereas copper has far better toughness and resistance to that type of damage. This is a big reason why people get cracking joints in aluminum radiator fins and channels but that rarely occurs in copper assemblies. Here, again the quality of the solder joint in a copper radiator is the concern, not the copper itself. It would be interesting to see a modern high end radiator shop utilize modern welding technology to weld a radiator together rather than solder it.

 

[ISPKI]

I havent looked it up either, but ive worked with it. All new transport vehicles, use aluminum for radiators, those are big hp ratings. The 3 core ive ordered is good to 700 hp. my factory rad did fine keeping up with my diesel , until it didn't. its a cross up between old versus new. ill be testing it, nd reporting.

I work extensively with copper alloys being that I am currently a resistance welding development and metallurgy engineer. I am swamped in copper development daily. It really is superior to aluminum but the automotive industry is primarily interested in doing things that are "goodnuff" and cheaper, rather than better quality. I have no doubt that a radiator made entirely out of AL60 dispersion strengthened copper or CU18200 chromium copper would outlast any vehicle it went into and outperform any aluminum radiator on the market BUT, who the heck would make it? AL60 alloy is easily triple that of a standard CU110 alloy and the welding process would likely need to be manual GTAW. Copper and traditional wave length laser dont play nice together but there are new "Green" laser machines that can weld copper without back reflection concerns. Again, the primary issue is $$$$

 

[OlKoot]

Now thats a good answer, and worth study. Thankyou.

 

[Clb]

@ISPKI
F
T
W!

You should write a short "stickie" for the tech articles stating these issues!
I know not one "parrot" I called about a replacement rad mentioned ANYTHING about those properties!
Hence my cleaning my stocker.

 

[OlKoot]

Dissimiliar metals in the auto industry has been major part of diagnostic anomolies. Such as electrolisis

 

[bilbo]

I would guess the fact that they are used in modern vehicles has more to do with cost. They make the same call you did. If you can solve the problem for a third of the cost, that's what you do.

I work in a sugar factory, and we have big evaporators that use tube sheet heat exchangers. On paper, the best possible material we could use there is a Cu-Ni alloy. They tried it years back and those evaporators worked better than ever, for a couple of months. The copper alloy was not compatible with the fluid and had corrosion issues. Stainless tubes are what are used now. Not near the heat conductivity but much better life span.

 

[OlKoot]

Distilled water 50/50 antifreeze mix, suggested for auminum radiators

 

[ISPKI]

Dissimiliar metals in the auto industry has been major part of diagnostic anomolies. Such as electrolisis

Very true! Metallurgical science has improved greatly over the years. Brake lines is a big one. Go back 40 years and no one heard of NiCopp lines yet nowadays it is used extensively to replace steel fuel lines. Plastics back in the day of our trucks were garbage and degraded over a few years, becoming brittle and cracking. Now, they have plastics that are bolted directly to the engine and stand up for decades.

 

[Slicknik]

(Excluding fan choice )

Yes copper trumps aluminum in heat transfer in element form .... but you have only scratched the surface between the two different styles of radiators
The oem style radiator is braised to the matting metal (brass ) which slows down your cooling capacity at the braised points and then you have to rely on the matting metal to cool your vehicle.

Aluminum rads has longer/wider tubes (1” to 1.5”) and are stacked closer together, while the copper tubes are shorter (typically 0.5” to .750” ) and are spread farther apart from each other.

More surface area and more tubes means that the aluminum rads can cool more efficiently will less rows/space than copper/brass rads can

Drawbacks? Aluminum rads are Cheap to produce , don’t last , usually have to be replaced under warranty, they also mess with the chemical balance (electrolysis ) in the cooling system. Coolant changes every year , coolant stripes and usually have to add an extra ground strap to the body from the rad.

Copper brass radiator seem to last longer but have higher upfront cost , and a 4 row copper/brass rad seems to have the same cooling coefficient as a 2 and 3 row aluminum radiator

 

[ISPKI]

See thats interesting. So the aftermarket aluminum radiators utilize a better design than the original factory radiators. Also - The brazing. Are they in fact brazed or are they soldered? It was my understanding that they were soldered. Reason being is that silver is an extremely common brazing medium for copper and silver is far superior to copper with regards to...literally everything except cost. Silver brazed joints would yield superior heat transfer when compared to any other type of connection. Soldered joints however would not as the solder is most likely a Tin alloy.

Also - is it being compared that a copper/brass radiator from the early 90s has the same cooling as a brand new aluminum radiator? Those are not apples to apple comparisons, although given the fact that brand new copper radiators dont really exist to my knowledge, then functionally speaking, that is the only comparison that really matters.

Again though, I dont see why an all copper radiator could not be made and am curious what the cost would look like.

 

[ISPKI]

Anyone know the dimensions of our radiators? I want to put together a materials list and see what it comes out at. I dont think its going to be pretty... 6ft of 1/4" copper tube is ~18$ from mcmaster. Although I could look into spools of NiCopp tubing. I dont know the thermal conductivity of it off the top of my head but I assume it is fairly weldable and available in large quantities for a decent price. Jegs has 3/8" diameter 25ft spools at 64$ or 2.56$/ft. I could feed them thru a roll former to straighten them out and oval them. I could test the weldability of NiCopp tomorrow.

 

[ISPKI]

Erp, scratch that idea, NiCopp/CuproNickel has terrible electrical and thermal conductivity which is really surprising considering it's copper content. However, it actually contains Nickel, Iron, and Manganese, all of which diminish it's thermal and electrical properties but make it much stronger.

I suppose another option would be copper plumbing pipe which is supposed to be pure copper (CU101? maybe?)

 

[OlKoot]

History shows, as you mentioned, silver solder, is very good with copper pipe/fittings, whereas, tin solder , not as much. This is key. In my dads day, hes 84, they would use benzine, my memory is going, a hotter gas than propane, getting the copper red hot, befadding the fusing solder. Has been forgotten.

 

[ISPKI]

Another issue with solder and the primary reason why I recommend people use mechanical crimp joints when doing electrical anywhere outside the cab. Solder has a major tendency to attract moisture and propagate corrosion. Probably yet another factor that contributes to the failure of soldered copper/brass radiators.