Heat Transfer Experts
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Aluminum VS. Copper-Brass Radiator: Price and Maintenance
If you’ve looked at buying a radiator, you’ve already noticed the differences in prices. It’s no secret that aluminum radiators are cheaper than their copper-brass equivalents since aluminum metal is less expensive. But what about the long term cost of maintenance and repairs?
Coolant Neglect: The Most Common Cause of Radiator Failure
Regardless of which type of radiator you have, you must regularly change out the coolant. The corrosion inhibitors and other additives that are put in the coolant break down over time. Just because your engine continues to run without overheating doesn’t mean your coolant is okay. Make sure you replace your coolant at the recommended intervals, and always use new coolant if you replace your radiator to avoid premature radiator failure. You can’t judge your coolant by the color because the chemical additives will breakdown without changing the color. Both types of radiator will be destroyed by failing to service the coolant. Here are a few things to keep in mind (for a full discussion of antifreeze, check out our “Do I Need Antifreeze in Warm Weather?” and “Can I Mix Different Types of Antifreeze?” articles).
- Change your coolant at the recommended interval (based on the manufacturer recommendations)
- New radiators should get new coolant to prevent accelerated corrosion
- Use a 50/50 mix of antifreeze and distilled water (some climates may require a 60/40 mix)
- Flush the coolant system periodically with distilled water to remove any used up antifreeze (Don’t run your engine for too long!)
- Never mix different types of antifreeze and don’t rely on color as your only indicator of the antifreeze type
- If you’re topping off your coolant level, always refill your reservoir with a 50/50 mix instead of just water
Distilled Water VS. Tap Water
We recommend that you always use distilled water when refilling your coolant. If you buy premixed antifreeze, then you don’t have to worry about this, but if you are mixing your coolant yourself this is very important. Tap water has many different chemicals and minerals in it that can adversely affect your radiator. The minerals in particular can speed up galvanic corrosion while the chemicals may alter the coolant’s pH or interfere with the antifreeze additives. Your only safe bet is to use distilled water.
Aluminum tends to be affected more by tap water than copper-brass. This is due to aluminum being more reactive to water to begin with plus the fact that it is less noble than most other metals (if you haven’t read Part 3 of this discussion, you may want to back up and read it before continuing). Because of this, an aluminum radiator may develop pinhole leaks. This is a good indicator that corrosion is taking place inside the radiator.
By comparison, copper is a very noble metal, so it won’t degrade like aluminum; however, the other minerals in tap water may degrade and accumulate onto the copper and block the flow of coolant. With copper-brass being much weaker than aluminum, too much blockage can increase the pressure enough to bust the tube walls in the core. Needless to say, this can result in having to replace the radiator core or the radiator entirely.
While aluminum may have a bigger disadvantage than copper-brass when it involves tap water, you shouldn’t be using tap water anyways. If you have to use tap water because of an emergency, make sure you flush your cooling system as soon as possible and replace it with a mix using distilled water. Your radiator will appreciate it.
Even a well cared for radiator can spring a leak. Vehicle vibration, heat, pressure, and general wear and tear will beat down the hardiest of radiators. When this happens, you may want to get your radiator repaired, but aluminum and copper-brass are not repaired the same way.
Copper-Brass Radiator Repair
Copper-brass’ weak spot is the solder seams between the header and tubes in the radiator core. Since solder is worked at relatively low temperatures, it is easy to have more solder slapped on over the leak. Many general mechanics can do this and apply a quick fix to the radiator. The biggest concern here is the fact that the solder will continually wear out due to its low melting point. The heat that your radiator is releasing is also being felt by the solder. Even though leaks originating at the seams can be easily repaired, you may have to take it in frequently for patch jobs.
Another note to discuss on copper-brass radiators and the solder is the issue of “Solder Bloom.” The lead and tin metals in the solder are less noble metals than the copper-brass; therefore, it will degrade and accumulate around the brass tubes inside the tanks. This creates a chalky white buildup around the tube and is known as solder bloom. Besides the fact that this is galvanic corrosion taking place in the radiator, chunks of solder bloom can be knocked loose from vibration and cause blockage inside the tubes. Like other radiator corrosion, this can be reduced by regularly servicing your antifreeze, but is still a big concern.
Aluminum Radiator Repair
There are a couple of draw backs to repairing aluminum radiators. Patching aluminum radiators requires welding, and many of your average mechanics won’t be able to do this. But there is a bigger issue with trying to repair aluminum radiators. We do not recommend patching aluminum radiators because the primary reason the aluminum fails is metal fatigue. Copper-brass can fail due to metal fatigue as well, but since it is a weaker metal, it tends to fail more catastrophically than aluminum (such as a blown tube).
If you have ever bent a piece of metal back and forth until it breaks, you’ve witnessed metal fatigue. The more a piece of metal is worked, the weaker it gets. Your metal radiator is no different. Between the buildup of heat and pressure during vehicle use and the subsequent cool down and pressure drop when the vehicle turns off, the metal walls of radiator will expand and contract ever so slightly. This continued process will fatigue the metal until it begins to break. Corrosion will also speed this process along.
The problem with patching an aluminum radiator is that only the visibly damaged area is fixed, but the surrounding area has also been fatigued and can still fail at any point. It’s a bit of Russian roulette in that you don’t know how long before the area around the patch will fail. The wall may last a week or it may last years, you just don’t know. Instead of patching a leaking aluminum radiator, we recommend re-coring it which re-uses the existing tanks (provided there is no damage to them) and puts them on a new core. This is the only way to eliminate all of the weak spots in a leaking aluminum radiator core.
Average Life Span
Given that there are many factors that influence the life span of a radiator, it’s best to look at the average lifespan of OEM radiators. A manufacturer is sure to use the proper style radiator and coolant for the engine and vehicle. In the case of copper-brass radiators, the average life span is six to 10 years. Aluminum is eight to 12 years. This may be a little bit of a shock for some people, but consider the main differences.
- Aluminum Radiator
- All aluminum – less risk of corrosion
- Stronger metal – more resistant to pressure and damage
- Lighter weight – less strain on mounting points
- Uniform heat transfer – no solder to inhibit transfer
- Copper-Brass Radiator
- Mixed metals – more risk of corrosion
- Weaker metal – more susceptible to pressure and damage
- Higher weight – more strain on mounting points
- Heat sensitive seams – solder has low melting point and inhibits heat transfer
This all adds up to giving aluminum an advantage over copper-brass for longevity and durability. If this is the case though, why are there so many people with stories of their replacement aluminum radiator failing when put in a car that previously had a copper-brass radiator? There is one simple solution to this.
Premature Failure of a Replacement Aluminum Radiator
If you are switching from a copper-brass radiator to an aluminum one, and you don’t flush and replace your coolant, then you are pretty much guaranteed to have the aluminum radiator fail. Why? Again, most people forget to regularly replace their coolant, and they will typically reuse the existing coolant if it looks clean. Therein lies the problem. The existing coolant will be depleted of the corrosion inhibiting additives and it will be carrying trace materials from the solder in the copper-brass radiator. Putting that mix into an aluminum radiator will result in accelerated galvanic corrosion. As we stated before, you cannot judge the quality of your coolant by color alone. Regular service intervals and replacing the coolant along with the radiator will pay off in the long run.
Price and Maintenance Summary
While there are many differences between how well aluminum and copper-brass radiators can hold up, the primary reason why radiators fail is due to coolant neglect. Both types of radiators will have their working life shortened and will ultimately fail if the coolant is not regularly serviced. Likewise, both types of radiators can last for many years with the proper maintenance. That being said, let’s review the primary differences in price and maintenance between the two.
- Aluminum Radiator
- Less expensive than equivalent copper-brass
- Stronger, more durable metal
- Average life span for OEM: 8 – 12 years
- More resistant to corrosion
- Repair requires welding skill and is not a guaranteed fix
- Copper-Brass Radiator
- Up to double the price of the aluminum version
- Softer, less durable metal
- Average life span for OEM: 6 – 10 years
- More susceptible to corrosion
- Solder is easily repaired but may need recurring repairs
Provided you take proper care of it, you can easily get more for your money out of an aluminum radiator than you can a copper-brass since you can buy two aluminum for the cost of one copper-brass and it will last longer. Don’t forget we discussed that both types of radiators have equal cooling capability due to the differences in construction (see the Part2: Construction Differences segment). Since aluminum will cool as well as copper-brass while being lighter, more durable, and less expensive, you may conclude that there is no place for copper-brass radiators any more. On the contrary, there is a very distinct place for radiators made from copper-brass, and we’ll discuss that in our final segment.
Aluminum VS. Copper-Brass Discussion Points
Use the links below to follow the discussion or jump ahead. While the purpose of a radiator is straight forward, some of the manufacturing and servicing considerations are not. If you found this discussion helpful, please share it with others.
I finally got around to installing the radiator and took a test drive yesterday (temp. was 90° F outside). Car ran great. No problems! Great job on a tough radiator.
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