My honeycomb radiator is clogged

December 1, 2009 | By Richard Prince


I am the proud owner of a 1928 Model A Business Coupe that I have restored.

I first received the coupe, which I called the rust-bucket, with a honeycomb radiator and I could not achieve enough water going through this 80+ year-old radiator. Rodding out a regular radiator with fins straight up and down is an easy task for me. The honeycomb radiator has no such straight tubes to rod-out. I’d say that close to half of the honeycomb radiator is clogged.

In addressing this issue, I first obtained a tall and narrow metal water tank from a local friend who makes ducts for houses. I removed both upper and lower tanks and tried boiling the radiator core in water.

This opened a few more tubes but clearly not enough.

Not even half of the tubes were working. I tried radiator flush several times, and based on advice from others I used Liquid Plumber, but nothing worked.

One day I handmade a rubber piece to fit on the end of a compressed air valve. After using radiator flush and flushing out with water, I placed the compressed air to each end and, to my surprise, this opened up a few more tubes that were clogged with rust. Now I would say that I have just a little bit more than half the tubes working.

I am an original-equipment kind of guy and would like to place this honeycomb radiator on my 1928 coupe.

I am disabled in a wheelchair and have figured out a way to drive my 1928 coupe around the neighborhood with the local kids who call me grandpa and I love it.

Any help you can give me on getting this honeycomb radiator core working again would be appreciated.


As you may already know, high quality reproduction radiator cores are available for the Harrison honeycomb radiator but they are not inexpensive at about $975 each.

I think you probably can clean out your old radiator without damaging it using a chemical rust dissolver or a combination of a chemical and an electrolytic process.

A service provider such as Redi-Strip can help you.

If you want to trydoing it yourself, contact the folks at The Rust Store ( They sell a variety of chemicals designed to dissolve rust and can provide you with something that won’t harm the radiator.