Part 1: Aluminum vs Copper-Brass Mythbusting and General FAQ

1. Aluminum doesn't rust.
Yes it doesn't, but that's just because rust is iron oxide. However, it doesn't mean that Aluminum isn't prone to corrosion, on the contrary, it corrodes far faster when inhibitors in your coolants have expired. In fact in certain scenarios, ie. salt spray air (seaside), stray currents, water only systems -aluminum will corrode faster,

2. Aluminum is a better conductor of heat than copper-brass.
Better than brass -yes, but far less conductive than copper by 1.7 times. In a radiator, this is negligible given brass tube walls in copper-brass radiators are relatively very very thin for it to make a difference.

3. An aluminum radiator is better than a copper-brass radiator or vice versa.
This is a misnomer. A properly designed aluminum or copper-brass radiator will perform according to specification. An improperly designed aluminum or copper-brass radiator will perform inadequately.

4. Aluminum is lighter therefore better.
For applications where weight and cost are more of a concern -yes. In more performance-intensive heavy duty environments -no.

In this case, more fins doesn't necessarily equate to more performance if air cannot flow through the radiator core, because aluminum fins need to be thicker by up to 3 times to make up for its lower tensile strength.

So to get more effective heat transfer area without blocking airflow, aluminum radiators need to add more rows, increasing its overall size.


5. Copper-brass is heavier therefore it is stronger.
Generally yes, but it really depends on the construction and material spec. Aluminum by its nature is prone to metal fatigue that results in stress fractures.

However, some radiator manufacturers have been known to actively hide information about tube wall gauges, simply relying on the fact that people do not measure what they do not see, so as to cut on costs.

This becomes critical in high performance/high reliability applications. Tubes with materials that are 30-40% thinner are used only for radiators in light vehicles. These are guaranteed to fail prematurely in demanding environments.

Again, use the right radiator for the job.


6. Aluminum is better therefore its more expensive.
We've answered the performance aspect of this above. Aluminum is actually cheaper due to being more abundant. It is also a very light material.

Copper-brass radiators will cost more simply because as a commodity, copper and its alloys are more expensive, and is a far denser material.


7. What about those plastic tanks?
Plastic tanks were introduced as a cost reduction measure for radiators. They consist of a fiberglass reinforced polyethylene composite and a gasket which is crimped to the radiator's header.

This solution is reasonably reliable, enough for it to be implemented across the industry. However, in a lot of extreme road conditions, those plastic tanks are subject to pressure and thermal cycling that results in premature wear.

Given the rate of expansion between the o-rings, the tanks, and the header, it will be the O-rings that will wear out first.


8. Which is the better replacement, Copper-brass or Aluminum?
Given performance parameters being equal, that will depend on your purpose.

If you're on a budget, aluminum radiators provide excellent value as replacements in most cars. Taiwanese, Thai and Indonesian made aluminum radiators actually work very well. At this point, I would personally avoid, China-made radiators for quality issues.

If the use of your vehicle is demanding, either commercial, heavy hauling/lifting or long distance driving -copper-brass radiators will be more suitable. Apart from greater pressure and corrosion resistance, copper-brass radiators are repairable just in case you find yourself out of town and your radiator is damaged, a typical radiator repair shop would be equipped to repair your unit.

Motorsports will likely lean towards aluminum because of weight and general availability. However, given how much equipment and technology is packed into typical engine bays right now, conventional aluminum and even copper-brass radiators would find it difficult to increase performance without enlarging the size of the radiator.

This would often necessitate cutting and grinding underneath the hood to negotiate for some room.

Next generation copper-brass radiators with more radical tube/fin geometries are required to overcome space limitations, allowing radiators to maximize heat transfer capacity within very limited confines. This is achieved through using razor thin copper fin gauges, so the radiator can be given more effective heat transfer surface area while maintaining the overall stock dimensions.

9. What about surplus radiators?
Unless you can't find a radiator and you're willing to risk your engine overheating, this has to be a your last resort.

Surplus radiators from abroad have already been subject to wear and tear. Its condition and "quality" are not consistent and you will need a bit more work than usual to make sure it gets things working for you. This isn't a situation as if its buying a pre-loved car. There are no standards for re-validating these.

Find a vendor that will customize one for you if need be -the risk isn't worth it.


10. There are a lot of cheap replacement parts flooding the market. Which do I choose?
Your engine's cooling system is something you shouldn't skimp on. The cost of an overhaul and downtime is worth more than a proper radiator.

A manufacturer is only as good as the warranty they're willing to extend and honor.