Chasing an overheating problem, I pulled the end caps of the heat exchanger on my closed cooling system. There is a fair amount of corrosion present, I suspect due to the neglected anode, which had disintegrated (I recently bought the boat - I wasn't the one neglecting it!). I was able to clean the cavities at each end of the heat exchanger but the tubes that pass from one side to the other are about 1/4" diameter and 18" long. I'd like to find a long thin tube brush to clean these passages locally so I can get back in the water this weekend; can anybody give me an idea where to look for such an item? I dunno who would stock such a thing, and I'd rather use a brush than just a coat hanger.

Thanx for any ideas! And don't forget you have an anode in your heat exchanger (if you have closed cooling)!

Have you thought of dropping it off at a local radiator repair shop and have them acid flush it and clean it out?
Just a random thought

I considered pulling the exchanger off and taking it in, but it's pretty accessible and looks simple to clean if I have the correct tool. I've been waiting on a sunny day here in the Pacific Northwest for months and they are finally forecasting one for this weekend; I'd like to have the boat operational and not down for maintenance so I'm trying to complete this task myself this week.

Wire coathanger

would something from a rifle cleaning kit work,,,,

Most auto parts stores carry a kit of brushes for cleaning out all the passages in an engine block. I'll bet one or more of the brushes in those kits will work just fine.

If not your local parts store, Summit, Jegs, Herbert mail order should have them.

I tried that on my old 454 exchanger. Unfortunetely, even the rod for a .22 rifle is too fat to go through. I ended up finding some long thin bristle brushes on-line from a medical supply company. They were cheap and did the job nicely but that's all I can remember about where they came from.