Heater core driving me insane

[65er]

I'm at my wit's end with the heater core on my Galaxie!  When I first got the car, the heater core was bypassed so one of the first things I did was got a new lifetime warranty heater core from Autozone and did the R&R.  Worked fine but about 10 months later it started leaking so I bypassed it again for a few months until I got my warranty core.   I did the job again and that was good for a few more months until I had to bypass it yet again.  I still had the original core so I sent it off to Classicheaters in NY to be re-cored, pressure tested etc... SO now I have a nice American heater built by a person who knows this stuff and I can trust it... maybe.   I keep smelling coolant though, and I'll get coolant on the ground under the damn core from time to time.  I replaced one of the hoses which was maybe too large (the AZ cores have one tube larger than the other, the original does not) and checked the clamp on the other like-new hose and it's all nice and tight.  When I feel around where the hoses attach to the core I'm not finding any moisture so seriously WTF this is pissing me off now.  The only thing I can think at this point is I guess replace the second hose that's maybe a year old and still looks new, maybe smear a little silicone on th core fittings and in the tube before I put it together... I guess if it's leaking at the connection that should stop it.  Maybe put some ginger or bar's leaks in the radiator but I'd rather not.  Being a factory air car, doing the heater core means taking the passenger side fender off and I hate doing that!

Any ideas on this S.O.B.?

[machoneman]

Often a leaky core will allow coolant to soak into some of the cardboard, foam padding and/or insulation under the dash.  Pain in the butt for sure.

Also any ribbed tubing (you know, connecting the rigid plastic core box to floor vents or defroster vents) can carry small amount of coolant on the inside for quite a long time since it doesn't evaporate. Short of yanking everything out, I'd watch the coolant level very closely for some time and always at the same time (say 10 hours overnight). If the core is truly leaking, eventually you will see the need to refill the radiator. JMO   

[fastback 427]

Wade, sorry to here your problem, but holy crap did I ever lmao!! I've been there with stupid problems too. I would replace heater hoses with gates or similar quality hose. Also as of late the new hose clamps are weak and bend with any torque. I get mine at a plumbing shop made in USA. What pressure radiator cap are you using? If all else fails maybe remove that sob fender and give her a test run!

[mlcraven]

Hah! Who needs heat and AC? After seeing what a leaky core did to the firewall and pass side floor in the Cyclone I went with the shade tree 'delete' option.

But I don't blame you for wanting to retain the comfort factor.

[65er]

Nah, I really need my heat and air.  It's my driver and I'm in Texas. Did enough Summers with no air already back in the day.  I'm getting too old for that sh... 

Pretty sure it's not just old leftover coolant, I can drive it for days and days with no problem, but if I run the heater it'll leak a bit.  The coolant level will drop about a half inch over a few days driving and I have a coolant recovery tank so I know I'm not just overflowing it onto the road.  Got a leak somewhere for sure.  I'm gonna be pissed if it turns out to be the core since I paid around $200 to have it fixed RIGHT rather than stuff another cheapo "lifetime warranty" core in there.  Been chasing a coolant leak all winter it seems.  First the heater control valve was pouring out of the weep hole, then the radiator cap seeping coolant on top of the radiator, which then got blown all over the engine compartment, and this persistent heater core deal.  I've never seen such a simple-ass system give so much trouble!  13 pound cap, by the way.

I used the Gates hoses throughout already, I'll look at the local plumbing supply for better clamps and hope that's all it is.  Fortunately I can reach up under the fender far enough to replace the clamps and hoses.

[machoneman]

Got it now (leaky).

I've often wondered about today's lead-free silver solder as a major part of the heater core issue. Helped a bud about 6 years ago with a massive basement project with about 50 or 55 solder connections needed (1/2"and/or 3/8ths copper pipe and fittings). Not too many years ago I'd do a bunch of similar fittings with a torch and never even worry about any of them leaking. On my bud's place, yikes! When we opened the fresh water valves, had about 4-5 leaks in very good looking joints. Was a bear to fix them up afterwards! This NEVER used to happen with leaded solder. 

[jayb]

I absolutely HATE heater cores.  One of the first things I ever did with my 67 Mustang when I got it in 1976 was replace that stupid heater core, and boy, what a pain in the neck.  Of course, being an inexperienced shade tree mechanic I tried to use the original hose clamps and hoses, and naturally after I got it all installed, it leaked.     I couldn't bring myself to do it again, so I bypassed the heater core for the spring and summer, and ended up fixing it the right way the next fall. 

The clamps are a good suggestion; most screw type hose clamps these days are not very reliable, and I've had brand new ones break and cause leaks right after installation.  Also, isn't there some dye you can buy to put in the cooling system, that will show up as a bright color wherever the leak is?  Or is that just with engine oil and transmission fluid? 

[fastback 427]

Yeah we tried the dye 20 years ago in the engine oil for a leaking galley plug. Turns bright under a black light. Also I was wondering if they pressure check the heater core with heat? Several years ago I had a head leak water on the engine when hot but wouldn't leak under pressure when cold.

[65er]

Here's a link for the place that I had do the work. 
http://www.classicheaters.com/Frame-1-page1namepage1.html?refresh=1258335936142

After receiving the heater core from your classic, vintage or antique car or truck for recoring we will remove the tanks and brackets, glass bead them, straighten or replace damaged necks, solder them onto a new core and test to the appropriate pressure. We will then inspect it for appearance and soak it in "Green Stop'. This solution prevents green corrosive build-up on the exterior of your heater core and also on the inside in case you don't install it right away.

I'm not going to start bashing on them though.  Even if it turns out to be the core I understand nobody's perfect and I'll be talking to the guys over there about solutions.  For now I'm ordering up some nicer clamps and will cut the last inch off the hoses when I change clamps to help eliminate the hose connection as a possible source of the leak.  After that I'll look for some of that dye and a cheap blacklight.   

Thanks for the suggestions guys.  The fun never ends, does it? hah

There, I bought this, looks like those should work well, huh?   http://www.ebay.com/itm/140902409757   

[Bolted to Floor]

Wade I feel your pain. I had an 85 mustang that I put several heater cores in, truly a nightmare.

For all of the high mileage cars I have now that tend to leak water, I use a mighty vac pump. It can pull a vacuum or build pressure. It came with an adapter to install in place of the radiator cap.

The last leak I had to chase on my surburban consisted of
Pop the hood on a cool engine
Install this gadget
Pressurize to system to match cap #'s
Look for water

Sounds easy enough, right!

[My427stang]

What are you using for a fitting at the intake manifold?  If it is non stock or if the stand pipe has rotted away, you can get air and steam pockets that shock the heater core.  Common problem on Mustangs, then they blow the heater core apart at high rpm.
With an aftermarket fitting, I either epoxy a tube that picks up water close to the water jacket floor with alum fittings, or I sweat a tube in if I can.  Either way works fine

Basically I copy this, but get as close to the floor of the manifold as I can, still allowing flow.

[65er]

I have the original heater fitting and it is in reasonably good shape.   Very interesting, I had wondered why that thing stuck down so far into the intake.  Makes good sense.

[sjmodels]

It may not help now but I get a female garden hose end repair and clamp it in a piece of radiator hose. I plug another hose with a big bolt, clamp them on a heater core screw a garden hose on it and turn the hose on.  This has always found leaks for me in the past. After my Griffin radiator leaked from new and they wouldn't warranty it I plan to check every thing before I install!   i'm helping a buddy fix his old starter solenoid on his 41  Ford cause the new one he ordered sticks and doesn't look to be machined correctly. I've gotten wear I trust used parts more than the crap they sell as reproductions.

[babybolt]

When you start a cold engine the thermostat is closed and during the warm up process the pressure in the cooling system can spike well above the pressure rating on the radiator cap.

In the late 60's Ford put restrictors in some intake manifold tubes that lead to the heater core.  For example, the Boss 302 heater tube is crimped at the bottom:

Here's a link to a CJ Pony Parts image (I've never bought anything from them, just an image I found easily on the web)

http://www.cjponyparts.com/heater-hose-fitting-with-water-restrictor-boss-302-silver-zinc-1969-1970/p/HHF11/

There's a lot of problems now with Chinese heater cores and A/C condensors, my sisters late model car has had 3 condensers installed - at least the parts were warranted but the labor is not.

[Drew Pojedinec]

Just a thought Wade.  $100 buys you a 300w electric heater that plugs into the cig lighter.