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Honeycomb Radiator


Am wondering if anyone has had any luck opening up the core on a '28 / '29 Durant honeycomb radiator.....I bought this radiator at the Monroe, WA swap meet a couple years back, It appeared not to be in too bad of shape other than the usual mouse nest, so I thought I would take a chance on it...I took it home and flushed the mouse nest out with a garden hose and surging it with water and air pressure in the bottom tank, I thought I had the core open but after installing it in the car it got hot....So, yesterday off comes the radiator and down to the radiator shop we go where he stuck an optic camera in the top and bottom tanks, we fount the bottom tank/core clean with tubes open, top tank was clean with some tubes open and others had rust chunks bridging part or all of the tube...So we did a more aggressive water/air surge and got a little more rust along with a couple more twigs from the mouse nest, we then checked it again with the camera and the tubes were still blocked, we also did a static flow check and of coarse it wasn't good....He thought the rust chunks were only blocking the opening of the tubes but thought that hot tanking the radiator would probably not remove the chunks and would do more damage than good....So here is my dilemma, I would like to save the radiator and at this point I have nothing to loose and everything to gain....What if I were to turn the radiator upside down, block of the filler neck and the top radiator hose bib and dump something in the radiator that would only desolve rust like maybe (Evapo-Rust?) then hook up air flow to the overflow tube and let it bubble or purkolate for a few days and then re-flush....Ya think this might work or am I wasting my time, any thoughts or ideas?

Where Are You From? Leavenworth, WA / Yuma, AZ

Do You own a car built by Durant? Yes , several

Re: Honeycomb Radiator

That's exactly what I would do with that rad. But why bother going to the effort of sealing the filler and turning it upside down? Why not fill the entire rad with Evaporust or Iron Out? Keep in mind if there is still twigs and other organic stuff in there, you will need a different agent to attack that stuff. I would concentrate on the rust first and if successful at clearing it out go back at the organic stuff. As you say nothing to lose at this point but potential for gain.

Where Are You From? Oro, Ontario, Canada

Do You own a car built by Durant? Yes

Re: Honeycomb Radiator

i think i would try filling it with c.l.r. calcium lime and rust remover,ive tried it on small parts and with some patience it works pretty good.

Where Are You From? so calif

Do You own a car built by Durant? devaux

Re: Honeycomb Radiator

An update on unplugging my honeycomb radiator....Radiator is now unplugged, freshly painted and back in my '29 coupe and it now runs cool.

In short, I simply stood radiator upright filled radiator with evapo-rust and injected air in the bottom outlet, this gave the core a constant backflushing perculation of evaporust up through the tubes, I kept the evapo-rust topped off to just above the top header plate, as tubes became unplugged I could add more air flow and more evapo-rust....Worked great....Will do an article with details as well as how to do a base gravity flow test.

Where Are You From? Leavenworth, WA / Yuma, AZ

Do You own a car built by Durant? Yes , several

Re: Honeycomb Radiator


What a great idea of using Evap-O-Rust.
I’m using it for two projects right now it works great.
I has saved a few chrome parts I thought were toast, amazing stuff.
You can get free shipping from amazon.com right now if you order the gallon size.


Where Are You From? Fremont, CA

Do You own a car built by Durant? 1929 model 60 Roadster

Re: Honeycomb Radiator

Look at it this way, you just saved yourself a bunch of money!. Some years ago I did research into having my radiator rebuilt to showroom condition. Interestingly I found that there is only one company left in the world that is making the Auburn style honeycomb radiator parts that our cars and others used in the 20's. That company is in England. I even contacted a company in New Zealand who advertises that they fix and make replacements for the honeycomb. I contacted them and they said that they even get their parts from England. Shipping over there would be costly, but most importantly to track the shipment would be hard. A call to Brassworks in California who have done a couple of our style radiators got me a quote of around $2,500 to restore or rebuild my radiator. So you have saved yourself a bunch.

Where Are You From? Oviedo, Florida

Do You own a car built by Durant? 1928 Durant Model 65

Re: Honeycomb Radiator

Rick, I found my best value on evapo-rust by buying the concentrate at ebay stores...An eight oz. bottle makes one gallon, free shipping at 15.90ea. and you will need 2 bottles...

What I found interesting was that the core was so plugged that it only took 4 quarts to initially fill the radiator to about 3/4" above header plate, then after about 2 1/2 days perculating and ocasionally topping off I drained out just over 5 quarts of evapo-rust....One thing to keep in mind is that all that rust and crud is a natural stop leak on these old radiators...In my case after perking for about a day there was a couple of seeps that showed up, so when I finished cleaning I drained out the evapo-rust and gave it a backflush with clean water then added a pinch of alum-a-seal and circulated that by purging for about 10 more minutes then put 3-lbs air pressure and no seaping, then I gave the radiator one last flush.....Mike, now I'm trying to figure out what I can spend that $2,500 dollars on that I don't have.

Where Are You From? Leavenworth, WA / Yuma, AZ

Do You own a car built by Durant? Yes , several


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