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Is recoring the radiator the only answer?


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The car has been running warm/hot this summer. Suspecting that the radiator was to blame as the outer edges never heated to the same extent as the centre I followed the advise on this forum and timed how long the radiator took to drain. At 25-30 seconds I think it was a safe bet to be the cause so I went ahead and followed the next recommendation which was take it out of the car and flush it through with CLR. It worked a treat and it now empties in under 10 secs so the diagnosis appears to have been correct.

 

However now that I appear to have re-established flow to more of the tubes the radiator is now weeping in spots where I suspect were previously plugged with rust and scale. I can't see holes just damp spots and stains on the core. 

The question is, is there an easy way to determine exactly where the leaks are and to fix them? Or am I just as well to cut my losses and get a new core fitted, which by the way is a costly option as I've been quoted $4000 for a rebuild with a new honeycomb core. If at all possible I'd like to save my old core not only because of the cost, but the new cores are a bigger hex (hole) than my original.

Any ideas?

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26-25 Buick,

   I am probably going raise a few eyebrows with this reply, but I have faced the same dilema, whether to re-core or not.  I have been fairley successful using 2 methods.  First I use a off the shelf radiator stop leak and it seems to do well.  If you can locate the actual leak, I have also had luck cleaning around it with a soft wire brush, and then coating it with a good epoxy applied with a small paint brush.  

Good Luck,

Glenn Manes

Wheat Ridge CO

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I am fortunate to have a good radiator shop nearby.  They put the radiators in a water tank and apply low pressure 1 to 3 psi, The leaks show up quickly and they then solder the leaks.  These old radiators are a challenge to find a reliable person to work on them.  Too many places want to recore the radiators at high prices.  The good news on these old systems is that they work at atmospheric pressure so they usually won't catastrophically fail.  If you are getting adequate cooling ( which can be a bigger problem) I would seek out a shop that will do the work with you watching to make sure they don't use too much pressure and you can see if the leaks are excessive.

 

Stating that it is weeping at a few spots, leads me to believe a few solder patches will get you on te road for many years.

 

Bob Engle

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I agree with Glenn Manes. This sounds like a perfect use for a radiator "stop leak" product like "Solder-Seal" or any of the others you can find at the auto parts store shelf. I had a similar situation with the radiator on my 1963 Chrysler New Yorker after I flushed and cleaned it. The cleaning made one of the seams begin to "weep" just a little dampness. I added a bottle of "Aluma-Seal" or maybe it was "Solder-Seal", which fixed the problem. That was 24 years ago and the radiator has never given me another problem and the car doesn't overheat on a Texas summer day.

Pete Phillips, BCA #7338

Leonard, TX.

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I had an overheating problem with my '15 truck. 

 

I used a number of flushes to clean out the radiator and got it so it would not over heat even on a hot day in a parade......but... because the radiator was so old ( 100 years old) and brittle it started to seep and then leak from driving.  I spent a year fixing a number of leaks. I media blasted the leaking area and then used JB Weld.  It held up good and never leaked in the repaired area.

 

That said, you never know when a new leak is going to sprout so I made the decision to bite the bullet and get it re-cored.  It is at the radiator shop as I write this note.   This IS NOT A CHEAP DATE on the truck because it required a core to be hand made and then reconnected to the tanks, etc.  I do not even know the final price yet for the re-core.  I dropped it off at a very reputable repair shop and said "fix it and please do not hurt me too much".   Now I am just waiting for the bill.

 

By having the new core, I never expect to have cooling issues again including overheating and leaking.

 

I chose to have it re-cored because I drive the truck and do not want to have problems.  If you are chasing a 400 pt car and do not drive it then patch it and make it look pretty.

 

On the stop leak, I would have low confidence that it will work on your vehicle as it is a non pressurized system and usually those fixes need pressure for the material to migrate to the leaking area and fill the leak.  Just IMO.

 

Edited by Larry Schramm (see edit history)
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I  too had trouble with my original radiator and after years of messing around with it I broke down, bit the bullet and had it re-cored. It was re-cored with the hex replacement type core and was very expensive. It was a huge disappointment. The car would over heat all the time. I flushed to block and got a load of rust scale out. Still it overheated. After nursing it along for years I found an original core in decent shape and presto, no more overheating. Unless yours is a show car and you are only driving from the trailer to the show field and back I would not do it. If you want, you can have my re-core for shipping cost. As far as I'm concerned its worth scrap value. I couldn't sell it to anyone with a clear conscience.  Others may have had different experience with the hex re-core. It would be good to hear from those who had positive results.

I know will be difficult to find a good original core so an alternative might be a modern core. Many have gone that route with great success. I have seen where guys have cut a sliver of the old core off and put it in front of the new one, just for show and it looked good.

Regarding the stop leak: I have used it and found it to work well. I would start with that and see how it goes. Later you can move up to solder or epoxy if necessary.

 

Dave

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I used this stuff, Seal-UP) successfully on my '38 heater core (recore estimste was &600+). It has held for quite a while and wont break the bank at about $6.

http://bluemagicusa.com/index.php/blue_magic/products/152/

 

Basically I believe it is "waterglass" which is sodium silicate. I have also used similar stuff on a 210 psi locomotive boiler to seal very minor weeps after a major rebuild.

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My only concern with stop leak is that the radiator passageways in these honeycomb units are very small and the system is open to the atmosphere.  Stop leaks seal by weeping out and then setting up in the presence of air.  If this stuff sets up in you radiator core, you won't be able to get it removed and you will surely have overheating problems.

 

Bob Engle

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Bob, I can agree with just about all of what you say about these old radiators.  A non-pressurized system like these were calls for these old radiators to be handled a bit differently than a modern unit.  I have three of these old Buicks and I am extremely fortunate that all three are in great working condition.  I have had all three flushed, back flushed, and checked at 1/2 pound of pressure with excellent results.  You saying that had your radiator checked at 1 to 3 pounds of pressure scares the daylights out of me.  You must be living a charmed life to not have that radiator simply rupture at the seams.  Something that has not been mentioned here is the coolant to be used in these old systems.  I run the Zerex 'original formula' (the Green stuff) in my old Buicks.  Running this formulation of anti-freeze does two things.  It will let the cooling system run a few degrees cooler and it will not attack the solder in the radiator.  As some of you on here have found out, recoring a radiator is not a cheap proposition.  I'm gonna do everything I can to keep mine running happy.  Just my two cents here.

 

Terry Wiegand

South Hutchinson, Kansas

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Does anyone actually manufacture new cores that are actually similar in design to the originals? I think that's part of the difficulty in (swallowing) the price is that even with a recore it's not the same as what's on the car.

 

There is a guy up in Queensland that makes hex cores but they're considerably larger than the original.  

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Some great suggestions here guys. I had no experience with the "radiator repair in a can" materials so really didn't know what to expect but it sounds like there has been some good experiences but the takeaway is there is some risk involved that it may well plug the tubes again especially if some of them have only have limited flow. 

 

Ours is definately not a show car in that it has developed a "patina" from its last restoration 40 years ago. I should of put in the first post, reliability is the key for us as we prefer to take it on the road rather than parking it on the grass. 

 

One of the radiator shops did suggest the face plate approach on a modern radiator at 50% the cost of a new hex but given I've tried to keep the car as close to original as I can I couldn't convince myself this was what I wanted to do.

 

Perhaps an oversight but it would appear that the car has not had anti-freeze in it for a long time probably because we never get freezing temperatures here in Melbourne. The downside is it doesn't get the corrosion inhibitor benefits in the anti-freeze either but the head and block appear to be in good condition when I took the head off last year. On the plus side I don't have to deal with a problem of having had the glycol been left too long in the car and breaking down in to its acidic forms.

 

Dave_B,  I'll ask because I'm sure everyone wants to know and wants to learn from your experience. Whose hex core did you have a problem with and any thoughts why it caused so much grief?

 

So before I go rushing out to buy a new core I do have a few things I can try as nothing ventured nothing gained as the radiator is not reliable at the moment.

 

P.S. Dave_B - I'll PM you and get the details of the radiator you have and how much it is to send it over. 

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I was dealing with a 32 radiator with the 1 1/2 psi  applied.  If I had to reproduce an old hex core, I would probably request the openings be a  bit larger than the original to allow more flow.  If the openings were .010" larger, no judge could ever notice the difference.     The exterior hex's could be the same size as the original.

 

Bob Engle

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26-25 Buick

 

i don't remember off hand who made it. It was 35 years ago.

 

I think the problem was a difference in design. When looking through the new one you could see that hex holes went through the core in a clean shot. It was a smooth passage. The original one has a lot of small sheet metal pieces that extend into that area. This does two things it increases the surface area for heat dissipation and it disturbs the air as it goes through bringing it more in contact with the metal surfaces. The old guys knew what they were doing. 

 

BTW I have an expansion tank on my car with a 4 lb cap. The rad handles it just fine. It's been on there for years. 

 

Dave

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. I agree about using "gunks and goos" in an old radiator. A chancy situation  I usually never use them. However, for a heater core that would cost $600, I was willing to take a chance. I dont NEED a heater in an old car.

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When I was having the same issues with my 25-25s original radiator I had done all the above and still the overheating but no seepage or leaking. The core had a small section removed and several soldered patches done by the previous owner. My radiator man said it was clean and flowed well after he went thru it. Same problem after I reinstalled.it. A local Mason-Dixon club friend sold me a 1925 standard radiator that looked to be in good shape. While I was doing a pre-cleaning prior to sending it out to get done at the radiator shop I put too much pressure with a flusher unit. When my radiator man checked it out he said it leaked like "someone took a shotgun to it". Expensive mistake! So I had that radiator re-cored with a HD modern core at over $900. No overheating ever since. The non honeycomb look does not bother me for my driver. Now if I can only get it running happily again!!

        25 Buick FRONT - Copy.jpg                 DSCF2850.JPG              DSCF4793.JPG 

Original radiator when I got the car in 2011      Re-cored and repainted shell, 2014        Jan 2016, with my powder coated bumpers

 seep marks and missing section in lower left.                                                                  and re-silvered reflectors.

Edited by dibarlaw (see edit history)
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For myself, I don't care for the look of a modern radiator core behind a shiny rad shell.  I had a 1/2" x 6" piece of flatbar waterjet cut to the original honeycomb pattern creating a male/female die, then cut 1/4" wide strips of 18 gauge mild steel, in a brake press I formed each individual strip and tacked the pcs. together with a tig welder (it took a while) to get the approximate size and trimmed it to size, then had it powdercoated. I had a modern radiator core installed but had the shop keep enough space in front of the core to allow for this false honeycomb.

IMG_0577.JPG

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4Hud a great solution to an often perplexing and expensive problem. It certainly looks great. 

 

Something equally perplexing is what type of core a cars radiator is.  According to my McCord Guide a rad passage has to have six sides to be called "honeycomb".  Four sides on their corner are "cellular" cores.  Brassworks uses the term honeycomb for eight different styles of cores including cellular, flat and several others. Five other sources on the internet only seem to confuse the issue more. It seems describing in words what type of core you have is even more difficult than the manufacturing of your solution to the problem.

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Something else that you guys might not know or realize is this - in the middle teens and on up into the middle to later twenties, Buick and General Motors sourced radiators from three different suppliers.  They were Harrison, Fedders, and Rome-Turney.  It is possible to have three different 1920 Buicks setting side by side and each of them will have a different style of radiator fins.  They will be completely original and correct to the cars in question.  Our 1920 Model K-46 was evaluated at the 2006 BCA Meet in Rochester, Minnesota and the remark was made to me later that the one judge thought I was trying to pull something funny by recoring the radiator and trying to pass it off as original.  There was also a 1919 Touring car at the meet that had a radiator with a different fin style.  The people looking at the cars did not have a clue as to what went on with the suppliers of parts to Buick and General Motors back at that time until they were educated.  Our car had less than 4,500 actual, and documented miles on it at that time and the radiator had only been off the car to be flushed, back-flushed, and checked at that time.  The head judge at that meet now knows about radiators and Buicks in that time frame.

 

Terry Wiegand

South Hutchinson, Kansas

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  • 5 weeks later...

An update on what we ended up doing. With a little bit of compressed air we finally managed to narrow the location of the two leaks down to two hexes. One in the middle of the radiator and one on the left hand side. Both were about 1/3rd of way down the radiator and towards the back of the core. After trying for a while to solder up the individual tubes I couldn't get them clean enough to be able to get the solder to stick so ended up going the easy fix and filled each of the leaking hexes with solder. I haven't filled them right to the top but just enough to cover the leaking tube. A lick of paint and unless you know to look it's quite hard to tell that they are anything but a normal hex.

 

An hour run today and not a drip of water so I've got my fingers crossed that the problem is fixed. So once again thanks everyone for all your help so this Harrison radiator can live on.

 

Now for the fun bit. An infrared image of the radiator after running for an hour around the suburbs. It would appear from the image that perhaps the radiator is not yet 100% clean but it's not too bad and 75 Deg C seems reasonable.

FLIR0387.jpg

 

Some other photos of the '26. Sorry temperatures are in Celsius.

Photo 1: Prior to starting. Photo 2-4 after 1 hour running. I found the vacuum tank particularly interesting as there has been some discussion over the years about the effect of heat on the tank but ours does not seem to be running much warmer than the firewall behind it. I'm guessing that the fuel level is about 1/2 way up the tank as the bottom is cooler

FLIR0375.jpgFLIR0388.jpgFLIR0385.jpgFLIR0391.jpg

 

 

 

 

 

 

FLIR0383.jpg

FLIR0390.jpg

Edited by 26-25Buick
Photo clean up (see edit history)
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Ben, it's a camera from a US firm called FLIR designed to take IR images. We actually use it at work for finding hot spots in insulation or fugitive emissions from valve stems but this seemed like a lot more fun thing to do with it. From memory this camera was about US$750

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Neil,

 

Best advice on old honeycomb radiators I ever got was to do essentially what you did, except I used black silicone sealant instead of solder to fill the honeycomb cell. I think not having to use heat is a benefit. Plus, you don't even have to take the radiator off the car or even have the cell immaculately clean. I filled probably a dozen or more cells on my 1912 Overland radiator this way, maybe 15 years ago with no leaks since and great cooling.

 

In a more traditional tube & fin radiator, where one or more tubes is leaking, I drill a small hole in the tube, near the top, and another small hole near the bottom, (assumes the leak is in between the two holes), and inject silicone sealant into the tube in those 2 places to seal it off. No more leak and you'll never miss a few tubes in an otherwise o.k. radiator.

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  • 4 years later...
On 4/21/2016 at 9:17 PM, Tinindian said:

4Hud a great solution to an often perplexing and expensive problem. It certainly looks great. 

 

Something equally perplexing is what type of core a cars radiator is.  According to my McCord Guide a rad passage has to have six sides to be called "honeycomb".  Four sides on their corner are "cellular" cores.  Brassworks uses the term honeycomb for eight different styles of cores including cellular, flat and several others. Five other sources on the internet only seem to confuse the issue more. It seems describing in words what type of core you have is even more difficult than the manufacturing of your solution to the problem.

Not sure about that.  We use the term cellular film core for a variety of cellular film cores.  Honeycomb is it but one pattern or style and we correct people if they mis-use it or they might just get what they ask for and not what they want.

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Don't over look the water pump if the suction side of the pump packing is not sealing good if will pull air in and not pull the water out of the radiator very good 

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I used a couple of gallons of evap-o-rust in my 35s radiator then drained it and filled it with distilled water and a corrosion preventitive.I then developed a steady drop on the lower radiator tank. I thought I'd try a bottle of Bars stop leak and so far so good. I also found a small crack at the top of the radiator which I sealed with j b weld and seems to be holding.

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  • 2 weeks later...

When I bought my 25A in 2006 and got it home and tried to drive it the temperature rose up quickly to the boiling point.I removed it and took it to my radiator man and was told that it had a zig zag core and could not be rodded out.After vatting and flushing it was found that someone had epoxied the lower tank on and it actually came off during the vatting procedure.The radiator was also found to be totally rusted out and was useless.After severall months of looking for a usable radiator I called American Honey comb radiator in Bowdoin Maine.At the time the price was $3,000 to recore it and They also had a 1 year waiting list.That was a tough pill to swallow but they did a concours job on it and now I run a Gano filter on it so nothing but liquid enters the radiator.My car now runs perfectly cool even on the hottest summer days.

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