heater core repair ideas...

Well as some of you might know, I am in the middle of a A/C type to non- A/C type heater box conversion on my '78. Upon re-installation I found a coolant leak which has been traced back to one of the end caps on the heater core.

Since new cores for under $150 are unobtanium, I figured I'd try to repair the existing core. The leak occured in the corner where 3 of the metal core to cap crimp tabs were missing.

I bent back the other tabs and removed the end cap to find the rubber gasket and end cap are in good condition as well as the mating surface on the core.

I should be able to find a way to save this core, no?

I'm figuring I need a way to bond the end cap to the core since the tabs are now missing. I'm guessing I need to glue these parts together while they are being held snugly together in c-clamps.

For rejuvenating the rubber gasket I'm thinking of using permatex oil resistant RTV silicone coated over all sides of the gasket.

For securing the two halves after crimping back what tabs are left, I'm thinking either a plastic epoxy or 3M super weatherstrip adhesive. Think this is good enough to hold the 13psi pressure the cooling system operates under?

Ideas? Thoughts?

A couple ideas for you -

Ok, this for your '78, which you will put up for sale soon, I think? So, don't fall into the DPO (Dreaded Previous Owner) trap as you prep this one for sale. :excited:

Have you considered taking it to an old-school radiator shop for repair? Since the heater core is such a bear to install and remove, I would think having a professional repair it would be the best course of action. Personally, I wouldn't fool around with a home repair of this heater core. I would put in a new one or take the old one to a professional for repair. [Don't take these comments as a reflection on your radiator repair ability, BTW. ]

If you go the home repair route, make sure it can hold 20 PSI. That's about 1.5 times the regular 13 pounds of system pressure, if it's ok at that pressure you know it will hold 13 PSI under extended use. That's how systems are designed, operating pressure plus a good safety margin.

Where did you find a new one for $150? That seems like a good price for piece of mind.

Henk in Holland has the new one for close to that, and I'm not planning to be the DPO so I plan to do it effectively.

The game plan is to repair the core, install the core/valve/hoses on the car (minus the HVAC box) and run it / pressure test it and inspect for leaks. If no leaks, then I'll refit the core into the box and complete the repair.

What about large hose clamps holding the end tanks on? May require some clearancing in the housing. Me, I wouldn't trust just glue, neither do car manufacturers.

budgetzagato said:

What about large hose clamps holding the end tanks on? May require some clearancing in the housing. Me, I wouldn't trust just glue, neither do car manufacturers.

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Oh yes! thanks for waking me up! I have stainless band-it style strap clamps and the buckle tool - that would work killer!

I was in a rush this morning... but I agree with Tom...

At least DRIVE it by a radiator shop and ask... I would think that a pro would find it difficult to charge you more than 50 bucks and guarantee his work as well.

Secondly, I would have it tested to 25 or 30 pounds to be sure.

Lastly, I don't doubt your abilities either as I've seen your work, but being retired as you are... I'm sure you can find better uses of your time.

Hope to see you soon...

OH... One more thing... the PO or DPO is only valid OFFICIALLY for six (6) months. After that... the New Owner (NO) becomes the Owner (O) and must accept responsibility for any past, present, or future Foul-Ups (FU's).

If you make sure you sell it LOCALLY in late March, by the time it gets cold in October... you will have officially Timed Out (TO) as the PO or DPO. Hope this eases your mind a little...

Ya know what causes me to scratch my head, Greg...

Its how some manufacturers managed to CRIMP an aluminum core and seal it to a plastic tank!

Black-Tooth said:

At least DRIVE it by a radiator shop and ask... I would think that a pro would find it difficult to charge you more than 50 bucks and guarantee his work as well.

Secondly, I would have it tested to 25 or 30 pounds to be sure.

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30psi? :help: Yikes it's a 37 year old car.I'll pressure test this thing at 30psi if you agree to run on a treadmill until your heart rate is 200bpm :nana:

Black-Tooth said:

Lastly, I don't doubt your abilities either as I've seen your work, but being retired as you are... I'm sure you can find better uses of your time.

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Retired? Oh no, $$ wise I'll be lucky to have that distinction in another 25 years. I'm still a working civil servant I'm afraid. I guess I could be retired if you count the new shoes I just bought for work (New Balance 609's).

Black-Tooth said:

Hope to see you soon...

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Yep I'm hoping for another sunday drive outing to crop up soon. If nobody steps up over the next month or so, I'll put something together again.

Black-Tooth said:

OH... One more thing... the PO or DPO is only valid OFFICIALLY for six (6) months. After that... the New Owner (NO) becomes the Owner (O) and must accept responsibility for any past, present, or future Foul-Ups (FU's).
If you make sure you sell it LOCALLY in late March, by the time it gets cold in October... you will have officially Timed Out (TO) as the PO or DPO. Hope this eases your mind a little...

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Haha indeed. The trouble is, as the car sits here, I keep wanting to tinker on it and open up a whole new realm of things to fix. After this heater valve is done, Ima gonna add the PBS SX1 cam and electronic ignition, making it both more powerful and 1978 spec smog legal. :thumbsup:

Rob... to sum it all up... I think you must be...

your own worst enemy... just like the rest of us!

As for get-togethers... On Sunday the 26th in Anaheim at Ed Decarbo's place. I will not know for a while yet if I can make with my wife being ill... but I'm still planning on it. Our initial response was about 4 or 5 of us... but like the Lord says, "where ever two or more are gathered..."

Contact Ed or Busman for details.