[Richard]

Bill,

To explain the issue a little more, let me expand on Jon's insight. The radiator or charge air cooler acts a heat exchanger. The radiator exchanges the heat of the water with the air passing over it. The way it is built, and the CAC too, is imagine a bundle of straight tubes with the hot water passing through them. Air passes over the outside of the tubes. Ok, that makes sense, but how do you keep the water and the air separate? Each end of the tube is pressed into a plate with a circular hole in it. The tube is then brazed or swaged to the plate. All of the tubes are fitted into a plate at each end. When the side tanks are removed from a radiator, you can clearly see the end plates. The metals used for the tubes and end plates do not like cyclical stresses. Cyclical stresses occur each time the radiator heats and cools. The stress is even higher than just the typical thermal expansion because the outside of the radiator is constrained or hard mounted.

This raises a couple of questions. Why make the radiator tubes out of metals that are fatigue prone. One, those metals transfer heat better. Two, those metals don't rust. Three, those metals are easier to fabricate.

If you add to the thermal stress any additional stress caused by bending the radiator due to the frame it's hard mounted to flexing, then you have a recipe for failure.

By the way, when the engineers use the word stress, think an applied force.

I like this Duralite concept of free floating the tubes in a silicone grommet.