Recently opened up my heat exchanger to search for some impeller vanes after an impeller failure. Found the vanes but realized the heat exchanger tubes needed some attention. Wire brushed the ends to remove the corrosion. The tubes themselves presented a different problem. I had read on IPhomeport (anybody else currently having a problem getting on that web site) that some one used a gun cleaning brush to accomplish this. I found that the correct size was a .20 caliber. Using two rods and electric drill I was able clean the tubes keeping the drill outside the engine compartment. The lower two rows of the heat exchanger were accessed thru the slot in the alternator positioning arm.
