Brass Radiator vs Aluminum and Plastic?



I’m looking for a replacement radiator for my 2000 Ford Explorer, 4.0L V6 SOHC. The current aluminum radiator with plastic jugs is leaking from one of the jugs. Past experience has shown that these radiators usually last 7 to 10 years before they begin to leak. I’ve had good luck in the past replacing them with a brass replacement, but was told this isn’t advisable with newer cooling systems. Why?

I once had an aluminum and plastic radiator repaired by replacing just the leaking jug, only to have the other one blow out a few months later. I was able to find a brass replacement radiator for that car, a Mazda Protege, and it outlasted the rest of the life of the car. I also have an '88 Toyota Supra, and it’s original radiator also failed, this time at the 8 year mark. It was replaced with a brass one, and I still have that car with no radiator issues.

I know it cannot be an interaction with the newer long-life coolants. I’ve used these coolants for years in my Supra and Celica with brass radiators and no problems. And these engines have aluminum heads with cast iron blocks, just like my Ford. So, what’s the real issue? Why would a brass radiator not hold up on my Ford?


I was going to pass this by until I saw the poster. Being as it is you, I will offer my first thought though have no evidence to back it up. My first thought was it somehow caused an electrical charge that a sacrificial anode could resolve.
A sacrificial anode, or sacrificial rod, is a metallic anode used in cathodic protection where it is intended to be dissolved to protect other metallic components. The more active metal is more easily oxidized than the protected metal and corrodes first (hence the term “sacrificial”); it generally must oxidize nearly completely before the less active metal will corrode, thus acting as a barrier against corrosion for the protected metal.

"Galvanic corrosion (some times called dissimilar metal corrosion) is the process by which the materials in contact with each other oxidizes or corrodes. There are three conditions that must exist for galvanic corrosion to occur. First there must be two electrochemically dissimilar metals present. Second, there must be an electrically conductive path between the two metals. And third, there must be a conductive path for the metal ions to move from the more anodic metal to the more cathodic metal. If any one of these three conditions does not exist, galvanic corrosion will not occur."
Hope this is a jumping off point for a solution to your question


I don’t know why replacing a plastic tanked aluminum core radiator with a copper core & tank would be any more prone to problems than replacing it with an OEM. Is this an automatic tranny and is the tranny cooler built into the radiator? Perhaps that has something to do with it, although I cannot imagine what.


I had thought of this, but my older cars have the same general metal components as the Ford. Aluminum heads and cast iron blocks. I was under the impression for decades that additives in coolant prevent galvanic action from taking place as part of their corrosion-resistance package. That’s why I don’t understand the advise I was given.

Thanks for responding.


Yes, the trans cooler is built-in, but so is the trans cooler in my Toyotas. I don’t think that’s an issue either. It just baffles me.


What you’re looking at is differential coefficient expansion rate of the two different materials. Aluminum core on plastic tanks. The aluminum core is going expand at a different rate than the plastic tanks. This puts a stress on the seal between these two different materials.

With an all copper radiator, the core and tanks are made from the same material and are soldered together, so the coefficient expansion rate is the same. So no leaks.



Yes, I understand that. The question is ‘why would a brass or copper replacement tank not be reliable in modern cars over plastic and aluminum?’ The advise I was given when I asked a radiator shop about getting a brass radiator to replace the plastic and aluminum radiator that is OEM, was that brass radiators are not reliable with some modern cooling systems, like that of my Explorer. I’m just trying to get a good idea of why.

I’ve had previous problems with these plastic and aluminum radiators, and have replaced them with brass in at least three of my previous vehicles, all Japanese makes. Since I tend to keep my vehicles for extended periods of time, like my '88 Supra and '92 Celica, getting replacements that last is important to me. This same radiator man admitted that the plastic/aluminum radiators tend to only last for 7 to 10 years, which matches my experience. He was unable to tell my why the brass radiators don’t last in some applications, and I was hoping for some sort of explanation from some of the better minds on this site. Do you have any thoughts on why a brass radiator wouldn’t last in a 2000 Explorer?

I keep up with maintenance, and flush-n-fill the cooling systems every 5 years. I started doing that 10 years ago when I switched to the long-life coolants. Before then, I stuck to a two year schedule. My vehicles all call for glycol-based coolants, and I typically use Prestone.


It may not be that brass won’t work. Maybe brass was available in older cars because they had brass originally, or folks still wanted brass to replace the plastic/aluminum. Now that brass is the exception, fewer folks ask for it, fewer ones are built, and maybe the cooling systems designed for plastic/aluminum aren’t easy to retrofit with brass.

Not that I actually know…


Just my 1 cent but I think a brass radiator will outlast any modern vehicle that it’s installed in and it’s quite likely any notions that modern cars will kill a brass radiator are fairy tales. My hot rod Ford has a brass radiator that’s been in there for half a dozen years with no problems at all.

The other half of my 2 cents is that a plastic/aluminum radiator is much cheaper and easier to manufacture; which is it in a nutshell.
I do some machine work on the metal lathe and mill and cringe whenever I have to buy a piece of brass stock. The last piece I bought from the aircraft salvage (about 8" long X 2" in diameter) set me back about 25 bucks if I remember correctly. It’s pricy.

A couple of years ago someone broke into a local scrap iron building one weekend by cutting a hole in the wall. They used the forklift to load several barrels of brass scrap onto a trailer or truck and those few barrels were valued at about 5 grand.


Electrolisis issues asside, it would appear that by far the greatest cause for the failure of radiators and heater cores is the repeated expansion and contraction from the pressurized cooling system. With 16+psi pressure caps being common and automobiles operated through repeated cold to hot cycles daily it’s surprising how durable the current radiators are. In the “good ole days” pressure caps were 6-8psi and the cooling system had a considerable volume of trapped air buffering pressure surges. And, of course, the fan was fixed to the water pump. At idle many cars today are programmed to reach 230* before the electric radiator fan cycles on and at that temperature the pressure is surging above the cap’s opening pressure. Maybe one reason old copper radiators lasted as long as the car was the car didn’t last that long.


I have never heard of compatibility or corrosion problems with all-metal radiators, but it is getting harder to find them. When my '91 Volvo plastic radiator failed after 8 years, I found a metal radiator for it and it has been fine since. However, I notice now that no one sells a metal radiator for that car. Only plastic/aluminum is available.

I have a couple of '97 BMWs that go through plastic radiators on a regular basis. I can get 100% aluminum ‘high performance’ radiators for them ($$$), but I have looked in vain for brass radiators to fit them.


My memory is hazy but I think the radiator in my hot rod Ford came out of an '87 Mustang GT and it’s brass.
As far as I know, most brass radiators have a short wire (or one should be added) to aid in the electrolysis thing. All of the old Subaru radiators were brass and they used a 3" wire from the radiator to the upper radiator support as a ground.

Aluminum is more prone to corrosion than brass anyway; especially with aged coolant.


The only thing that make sense to me is that the brass radiators that radiator shop were buying was junk. I have read in Hot Rod that all aluminum(no plastic tanks) are better from a heat transfer standpoint but I don’t know if it’s true.


Plastic/aluminum radiators are lighter and they don’t have any lead in them. Any industry that uses heavy metals has to pay a lot for that privilege.

If the replacement radiator lasts 7-10 years, the Exploder will be 17-20 years old. How much longer do you plan to keep it?


Can you even GET a brass radiator?? Who makes them?? How long do you intend to keep the Explorer??

Brass radiators are REPAIRABLE…Plastic / aluminum are not. That’s the difference. Radiator shops are fading fast…


Aluminum/plastic radiators are repairable. Its usually the rubber seal that ages and leaks, but it takes a special tool to take them apart and crimp them back into place and I don’t know where the radiator shops get the seals from.

As for the electrolysis issue, the aluminum will get deposited on the brass, but the big issue is the source of the brass. I got one of these once, it was made in the Philippines and it only lasted about a year.


Until the wheels fall off. I still drive a 22 year old Supra, as mentioned above. And I have a 42 year old Thunderbird in the garage that’s undergoing a complete restoration.