Aluminum Radiators

Look under the hood of a car built in the 80's and earlier and you are likely to find a radiator of brass/copper construction. Brass/copper is an excellent conductor of heat, but it is relatively heavy. Brass copper radiators use a lead/tin solder to attach the tubes to the headers and fins. The solder can slow down heat conduction somewhat as it does not transfer heat as well. In addition, the solder can react with the brass/copper and chemicals in the coolant creating a white scale that builds up inside the tubes of the radiator. Eventually, this can lead to clogs in the tubes which is very difficult to clean effectively, and a re core or new radiator becomes necessary. Most brass/copper radiators found in our 60's and 70's Buicks were 2 or 3 rows of 1/2" to 5/8" tubes. Bigger tubes mean more tube to fin contact all else being equal, and better cooling, but brass/copper being relatively soft limits tube size to 5/8". Back in the day, the small and big block Buick V-8s were equipped with 190 degree thermostats, and it was not uncommon for the engines to run with a coolant temperature around 200-210 degrees. Higher coolant temperatures are better for longevity, minimizing oil contamination, and increasing gas mileage, but it also increases the chance for ping and detonation. Most of us concerned with performance like the engine to run somewhat cooler. Running an engine too cool can increase contamination of the oil as fuel and water are not evaporated out of the oil as effectively. I think 180 degrees is a good target to aim for. One of the most common problems in our hobby is an engine that runs too hot on a consistent basis. Building an engine that has more power is one reason, more power creates more heat, and boring a block to clean up the cylinders sometimes results in an engine that can potentially run hotter.

In the 90's, manufactures started using aluminum radiators. Aluminum is not as good a conductor of heat as brass/copper, but it is lighter, and more importantly, stiffer. Aluminum can support tube sizes up to 1 1/2", and as mentioned earlier, bigger tubes mean more tube to fin contact and better cooling. As a result, aluminum radiators commonly only need 1 or 2 rows to get the job done. Later model Buicks use single row radiators with 1" or bigger tubes. They are a favorite with racers because they are light and cool great. The Spectra CU 161 radiator available from www.rockauto.com will work in our Buicks. The only problem you might have is the upper hose connection is smaller so you might need a bushing, and the lower hose connection is a bit bigger so it might be a tighter fit. The OEM radiators in our Buicks had 1 1/2" upper and lower hose diameters. Other aluminum radiators on the market have the bigger lower hose connection. The Chevy radiators used a bigger lower hose (up to 1 5/8") so it is common to see that bigger size when shopping for radiators. There can also be some interference with the petcock and the core support if the petcock comes out of the back side of the radiator like stock. The important thing to remember is to steer clear of any aluminum radiator that has more than 2 rows of tubes. These radiators use smaller tubes and that defeats one of the purposes of using aluminum in the first place. They might even be inferior to an equivalent brass/copper radiator. Carefully check the specifications of any radiator you see on E bay or other suppliers. You want tube sizes of at least 1" and no more than 2 rows. In June of 2000, I bought an aluminum radiator from Griffin Thermal Products. I ordered it on the phone and they built it as a drop in radiator for my 70 GS. It has 2 rows of 1 1/4" tubes. I had them build it with 1 1/2" upper and lower hose connections, and I had them move the petcock up 1". It fit perfectly. I still use that radiator today. It looks as good inside as the day I bought it. My current engine uses a 180 degree thermostat and I have never seen the temperature vary more than 5-10* above that even in the very worst conditions of high ambient temperatures and stop and go traffic. You can still order a custom built drop in aluminum radiator, but they are costly. I paid about 530.00 for mine back in 2000. There are also universal aluminum radiators available in the Jegs and Sumitt catalogs. Like I said, pay attention to the specifications and measure your existing radiator carefully before you order.

 

Relevant thread,

https://www.v8buick.com/index.php?threads/ae161-back-in-stock.364120/