Heater Core repair

[FINOCJ]

Have had a slow leak in my oem heater core. I run a 2nd auxiliary heater core in the cab, so I just bypassed this one for the time being to get things back on the road. So, how do I go about fixing this thing?
I've never pulled one apart beyond this point - so it looks like I need to pop the end caps off to separate the tubing on the inside from the fins on the outside? Is there an easy way to do this?

Also, how can I check for where the leaks are (pressure test) without any special tools? It looks like it might have had some repair work on one of the outlet nipples....If I had a local shop that could test it and fix it up I'd be okay with that, but not sure where around here anyone does that anymore and thinking I can probably getting done myself. The two radiator repair shops I've used around here fall in the category of definitely will never use again and the better one is a maybe....

And not sure if you can find exact aftermarket replacement...but will take a look.

https://beamingpix.com/images/2019/02/23/P_20190223_130514_LL.jpg https://beamingpix.com/images/2019/02/23/P_20190223_130538_LL.jpg https://beamingpix.com/images/2019/02/23/P_20190223_130550_LL.jpg

[Getaklu]

A bucket of water and a little compressed air will will point you in the right direction as far as finding the leak. Not sure on tearing it down, maybe you will get lucky and the leak will be at the nipple.

[Jim]

What's a radiator cap run at... 14 to 20 PSI?

Perhaps hack up a rad hose to air compressor hose, set your air compressor regulator to 10 PSI, and put the heater core in a water tub and watch for air bubbles?

[FINOCJ]

What's a radiator cap run at... 14 to 20 PSI?

Perhaps hack up a rad hose to air compressor hose, set your air compressor regulator to 10 PSI, and put the heater core in a water tub and watch for air bubbles?

This is exactly what I just finished doing...no bubbles anywhere...maybe I am just an idiot and it was all in a hose connection?

[Patrolman]

I see the deformed inlet. That will allow for a hose to leak at the connection. Does the hoses connect into the cab or under the hood (does the heater core pass through the firewall)?

[Patrolman]

Looks like replacements are easy to find. I would simply replace it.

https://www.partsgeek.com/gbproducts/HC/117407-09121019.html?utm_content=HC&utm_term=1964-1965+Jeep+CJ5+Heater+Core+Spectra+Premium+64-65+Jeep+Heater+Core&utm_source=google&utm_medium=ff&utm_campaign=PartsGeek+Google+Base&gclid=Cj0KCQiA-8PjBRCWARIsADc18TKCTdLsaiFTSnQy6F8q1VKUVXktQrhzUlp tfFtrD9_Ata7c6Nxn_64aArHUEALw_wcB&ad=47433950292

https://www.autozone.com/cooling-heating-and-climate-control/heater-core/jeep/cj5

https://shop.advanceautoparts.com/p/carquest-heater-core-399211/3890554-P?utm_medium=ymme

https://www.oreillyauto.com/shop/b/cooling---heating-16773/heater-core-12446/bc659fa1024a/1965/jeep/cj5

[CS79bronco]

I would put some radiator flush in, fill with hot water, shake real good and let sit over night then flush real good. Air pressure might have pushed crud into a hole so it couldn't leak.

[Jim]

maybe I am just an idiot and it was all in a hose connection?

It'd be GREAT if it was a hose-connection issue - as that's an EASY item to resolve.

As there might be a question if the test was sufficient, I'll drop this thought - the heater core is being tested cold and not at operating temp (thought to a very small hole that only opens up for fluid flow when the metal heats and expands). I put this rather low on the list thought.

How easy is it to remove/replace the core? If time consuming, perhaps leave the core out of its installed location and only connect the heater hoses to it and leave the core, loose, in the engine bay / front fender. You'd be able to run the motor and get it up to operating temp & pressure where you could (with gloves) hold the heater core and turn it around to inspect for leaking.

[FINOCJ]

I pressure tested as best I could...found nothing...so put it back together nice and clean. Fixed up the hose connections as best I could with new clamps etc. If it continues to leak I will try to replace with aftermarket....
Fwiw...this core is completely in engine bay...if it leaks its no big deal. I am a have a manual valve in the heater hose line that can shut off flow to ensure I can drive home.

[Patrolman]

Fwiw...this core is completely in engine bay...if it leaks its no big deal. I am a have a manual valve in the heater hose line that can shut off flow to ensure I can drive home.

That is really good. Much safer, and makes it so much easier to service. Hopefully it continues to work for you!