ALUMINUM OR COPPER RADIATOR

[garysleeman]

Both are available in the aftermarket, which is better? Will the aluminum with plastic tanks hold up to the vibrations from a diesel? I read the cooling efficiency is close to equal. The advantage of aluminum is the weight reduction but will they hold up? From the factory looks like every model truck except the diesel (1989-1990) was aluminum.

[mpascino]

I have an aluminum replacement in my 91 burb. So far so good. Be careful though, the replacement aluminum core ones do not fit exactly the same way. Watch for things such as the shroud that may rub the fins.

[Larry Andrews]

Who knows what the truth is, but www.radiator.com (http://www.radiator.com) claims that copper radiators will move a lot more heat than aluminum ones will.

[dieselcrawler]

I don't have an answer as to which rad is better, but in so far as how well alum and copper conduct, I'll put in my 2 cents worth.

I'm an electrician by trade, and both alum and copper wire is used. However, for our uses, you have to use diffrent size wire, depending on if you are using alum or copper, because copper is a better conductor. Electricity and heat both work on the same principal, each is transfered thru the metal, so I would think that you will have better heat disapation with the copper radiator. Not that it is as much of an issue with a radiator, but there is less of an expantion and contraction issue due to the temp changes with copper also.

However, there are meny well made radiators out there, made of both alum and copper.

Greg

[whatnot]

But doesn't aluminum wire usually have much bigger strands?
Fine stranded copper wire is rated higher than regular copper isn't it?

[dieselcrawler]

As far as alum and copper are concerned when conducting electricity, the same size copper wire will conduct more than an alum wire will. It's a long story, one I won't get into the details here, but it boils down to the cross-section of the wire, the surface area of the wire strands, and a few other things, if I understand the workings of it all correctly. Exactly how this relates to radiators, well, someone else will know more than I. I expect that you would need an alum radiator to have slightly more surface area than a copper one, to have the same ammount of cooling capacity.

The way I would look at it, is that the copper one will be more easily repaired if the need should arise. It can be sodered, and the alum one would cause more headaches when it might need repaired.

Does anyone know if there are any diffrences as to the corrosion resistance of eather one?

Greg

[NH2112]

From what I understand aluminum is very eager to give its electrons away, so it'll be affected by electrolysis a lot sooner than copper. Just take a look at how many 20-year-old copper-brass radiators are still in use, and then try to find a 20-y/o alumnum rad.

[JeepSJ]

As a heat conductor, copper conducts heat better than aluminum. Where a typical copper/brass radiator gets into trouble is that the fins are usually soldered to the tubes using LEAD. Lead is not a good heat conductor. As a result, an all aluminum radiator will outcool a typical brass/copper of the same size. We had a 3-row lead/copper in our hot rod El Camino (it lives in Las Vegas). We could not keep it from overheating in traffic. We installed a 2-row aluminum and it runs between 195-200 all the time (195 t-stat), even in traffic with the A/C on. FWIW, I plan to run an aluminum radiator.

[garysleeman]

My first replacement was a 2 row aluminum but leaked right out of the box, the dealer couldn't find another aluminum so I ended up with a 3 row copper. We're luck if we get a half dozen days above 90 degrees in my neck of the woods so I don't expect overheating problems. If I was drag racing the extra weight of the copper would be a concern.

[DmaxMaverick]

Comparing the two, an aluminum radiator requires half the rows of copper for the same cooling efficiency.

The reason has nothing to do with the conductivity of the metals. It is the pressure.

When comparing two radiators of the same cooling efficiency, one aluminum, and one copper, there is one key difference. The cross section of the tubes. Aluminum is significantly stronger than the copper, allowing much wider tubes of the same thickness of material. Wider tubes offer more surface area to conduct the heat away, and allow much better flow characteristics. Larger, fewer tubes offers much less resistance, and a more even flow dynamic, adding to the cooling equasion.

All things being equal, copper conducts heat better than aluminum. But all things are not equal. Strength of the metals plays the biggest part. With aluminum, you can use a wider, thinner tube for the same, or higher pressure system.

To put it into perspective, consider the tubes. They are not round. Add enough pressure and the material will try to get round. Aluminum resists this to a much higer degree than copper for the same efficiency rating.

For these reasons, aluminum will cool better than copper cores. The real evidence is the design of the radiators. The copper radiators have metal tanks, which is a part of its cooling ability. The aluminum radiators have plastic tanks, which offer little heat transfer ability. If the aluminum radiator had aluminum, or other metal, tanks, the cooling ability would be even greater. This is one advantage to using a performance/race rated aluminum radiator. They have aluminum tanks, and take advantage of the additional cooling ability.

Any questions?

Class dismissed.....

[dieselcrawler]

Not now! *grin* If I did, I think you covered them all... great info, thanks!

Greg

[JeepSJ]

To back what Dmax said, the tubes on the aluminum unit are huge - they are like 1" wide and about 3/16" high.

Regarding the heat transfer information, I got that from the BeCool radiator site a while ago. Looks like they have redone their site - the link I have to their tech page is dead.