'56 Buick heater core repair

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'56 Buick heater core repair

Postby Gael » Sun Oct 24, 2010 7:26 pm

A bit off topic but you guys helped me years ago when I was reviving the original AC for this car! Thanks for that!!

It got unusually cold in NC last winter and I adjusted the antifreeze accordingly. The only thing I didn't do was to turn on the heater when I ran the engine to get the upgraded antifreeze distributed. Soooo... I got some leakage from the heater core this spring. I clamped off the hoses and am just now coping with that as winter is on its way.

Took the core out and pressure tested it using my lungs. I found two places it was leaking. The core is a 2" thick copper "corrugated cardboard" type with the water tube form pressed into the in the middle of each vane. I know that I can fill the air channel that the bubbles came out of with solder, pressure test and fill others that open up. The core was completely rebuilt maybe 7 years ago so it is a good core.

I know solder is the better method but the leaking areas are close to the top which is soldered on and I am afraid that heating the fins close to the top will release the solder holding the top on. I was thinking (may be a bad thing) couldn't I just fill the air passage with high temp RTV? It would avoid un-soldering the top and would be a lot less work. Also, what should I pressure test the core to? I have a compressor that tops out at 120 psI but I think the radiator cap maxes out at maybe 18 psi.

Thanks in advance for your help!

Gael
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Re: '56 Buick heater core repair

Postby Tom Greenleaf » Mon Oct 25, 2010 1:30 am

Speak for my self but I consider heat part of the A/C system even if just for heat issues like this. No matter - just that it won't get seen by as many regulars here so start another if you aren't happy about responses.

The core you described is what I would call "Ribbon Cellular" type vs tube and fin. Not sure as I never was a radiator repair person but I think that style is going to be tricky to solder up. Unless you are real good at this I'd just send it out if you can still find a dedicated radiator shop. They used to be several around me and now new is just more practical. Even though only seven years since it was fixed up or whatever done I'd do it again if a new core was needed on the old tank ends is what I'm guessing it looks like.

Thoughts etc: What's with "adjusting" antifreeze? Just put in 50/50 all year round and leave it there and change it as per suggestions of the brand and quality you choose. If you are reducing this to near water you are inviting corrosion which might have been the early failure. For testing pressure if you do try to solder this up yourself really doesn't need be more than perhaps max 20psi.

Pressure cap: 18lbs is WAY too much IMO - remember your water pump has to tolerate that too. This should have a HUGE radiator and I'd have a 7lb cap on it. 7 lb pressure gets you an extra 21 degrees Fahrenheit before boiling or roughly 3 degrees per lb of pressure. It's old - I wouldn't ask the thing to max out pressure. Can't think of a car that really used 18lb pressure caps but I know they are out there for sale. There may have been a couple but 15-16 has been common for ages on end. Since this no doubt didn't come with a recovery tank you still could put one on and take advantage of more radiator space. They should still sell those as add ons and just take it out if showing the car or something. Different cap needed for a closed system vs open - two rubber gaskets not just the one such that it will draw back coolant from the recovery tank and radiator/cooling system would remain without air which would be good for it. There should be plenty of room to just hang/wire tie a recovery tank.

Sent that core out and get the same style or regular core part of it is what I'd do,

T
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Re: '56 Buick heater core repair

Postby Gael » Tue Oct 26, 2010 7:39 pm

Thanks, Tom for the reply. Adjusting the antifreeze... Temps were going down to just over 0 degrees and I went ahead and tested it. It was good for maybe 20 above so I added antifreeze, ran the engine and put a droplight near the lower radiator hose. Didn't think of running the heater or to put a second droplight in the car near the core. Didn't use the car until maybe March and that's when I found out about the core being busted. I'll check the manual for the radiator cap pressure....

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Re: '56 Buick heater core repair

Postby Tom Greenleaf » Wed Oct 27, 2010 5:57 pm

Laugh - fell asleep with this still on the screen so there might be something in between here.

ALL my own vehicles have 7lb radiator caps. All have 50/50 antifreeze and not played with. I can get away here with the 7lb = 21 extra degrees F even if plain water.

So can this car. Recovery tank really would help on this but do what you want. Cap # 703-1444 without even looking I know that off the top of my head. Not as old as this car but I drive and rely on cars over 20 years old and always did!

T

Not giving away my age just yet but went thru college with a 1960 Rambler which was about 19 years old at the time I bought it............$100 bucks .......... those were the days!
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Re: '56 Buick heater core repair

Postby Gael » Fri Oct 29, 2010 3:48 pm

Tom, yeah, I had a hose leak and just added water the summer before last. Didn't think it would make much difference but it did. When it was forecast to be really cold I remembered what I had done, got with the program and adjusted it.

You are spot on, the manual calls for a 7 lb cap but a 13 lb cap for cars with AC which this has. We have some pretty hot summers here so I stuck with a higher lb pressure cap since I wanted to use the AC. I sent the AC parts away and had them rebuilt (finding a compressor bearing was a bear!) and installed them myself along with new hoses. Had my radiator shop guy test, evacuate and fill with R12. The only problem was I could never get the hot gas bypass valve to seal completely I haven't charged it up in maybe 7 years. The AC works well when it is charged, but it will hold a charge for only 6 -8- months. I suspect R12 is still available but I shudder to consider the cost. Don't want to go through the brain damage to convert to newer refrigerants. I did a little research on this years ago but couldn't convince myself that it would work satisfactorily.

The car is a fun one to drive.... it is a Buick Super, has the nailhead engine, is a coral and green color (sounds odd but it is a stunning color combination.) I would attach a pic but couldn't figure out how.

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Re: '56 Buick heater core repair

Postby Tom Greenleaf » Fri Oct 29, 2010 7:32 pm

Oh my! I grew up in cars like that. I really can't speak specifics for the era but do have a clue.

Keep it R-12 if you can. 134a will work but leak even faster and lose 15% BTUs of ability right out of the gate.

Check it out - R-12 has lost price big time. Yes you need a cert to buy it but you can do that online!

T
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Re: '56 Buick heater core repair

Postby Gael » Mon Nov 01, 2010 7:36 pm

Tom, interesting.... You can still get R12 and the price might be low enough to keep it charged! I thought about getting the certification on line and might just do that! But where do I get the R12? NAPA or someplace less expensive? Also, I'd need to figure out how to pull a vacuum, how to seal up the hot air valve (is there some sealer that I can use?) I know, I know, nothing but oil and refrigerant in the system but... The guy who charged it last did put dye in, which is why I know it is the hot air valve. The system has not be open since 2003 so would I need to put a new dryer in it? I have a set of gauges for R12....

Thanks for your comments, I appreciate your help!

PS, got you on the age thing. The car was made when I was 9 years old! BTW, I used silicone sealer to fix the heater core. Just squirted it down the air passage from where the air bubbles were coming and let it cure. I know it is heresy but it is cheap and I am retired. Pressure tested to 30 lbs, no bubbles in the kitchen sink.

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Re: '56 Buick heater core repair

Postby Tom Greenleaf » Mon Nov 01, 2010 9:52 pm

At this point keep it R-12 if at all possible. Check Ebay - others - it's still out there and made NEW in some countries! I don't need any and haven't looked. AZ still sells the can taps new - get one or more! Parts stores and shops GAVE me thier R-12! Yikes! No demand for it. I do have ONE OE R-12 car of way 2 many cars and if not fast leak er which it isn't will let it bet R-12 but NBD as that exact car converts well and easy. Did get hot here this year - 107F but only for an hour then calmed down.

LOL but the suggestion is keep it R-12,


T

PS: Site sells tools but not refrigerant. I don't need any but would be asking the regulars here if needed.................Where are you? Cold where I am already! 44F outside right now! Laugh - that would be a decent vent temp!
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Re: '56 Buick heater core repair

Postby Gael » Tue Nov 02, 2010 2:56 pm

Tom, I'm in Charlotte, NC. No worries, I'm in no hurry at this point and I need to get certified and buy enough R12 to keep it charged. I still need to figure out how to seal the hot gas bypass valve. If I remember correctly, there is a sealer that will work and not contaminate the system. Gael
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Re: '56 Buick heater core repair

Postby Tom Greenleaf » Tue Nov 02, 2010 10:13 pm

NO SEALERS - EVER! Don't trust their bull crap and the damage can be nasty!

T
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