• Hello Guest, we are proud to now have our Wiki online that is completely compiled and written by our members. Feel free to browse our Jeep-CJ Wiki or click on any orange keyword when looking at posts in the forum.

Misc. Leaky heater core

Misc. Leaky heater core

Scout1067

Old Time Jeeper
Posts
1,220
Media
3
Solutions
1
Thanks
75
Location
Germany
Vehicle(s)
1981 CJ7, 258, T176, D300, D30 front diff, AMC 20 rear diff, Weber Carburetor, BDS 2.5" lift
I replaced my heater core and the hoses from the radiator to the core in January. It now leaks where the hoses enter the core. I have adjusted the hoses and tightened the hose clamps as much as possible and it still leaks. Am I missing something here or is it time for a little hi temp RTV or some other sealant to stop the leak?

I am losing about a quart of coolant every time I drive it to work.

Sent from my SM-A528B using Tapatalk
 
When I replaced mine last year, just removing the old hoses cracked the seam where the copper pipes attach to the core. So I will need to replace it again. For bow I am just bypassing it
 
I had a slight leak 1 time and used 2 clamps, but yours may be cracked.
 
When you replaced the hoses, did you ensure the right sizes? Don't mean to be facetious, but the connection on the water pump and the ones on the heater core are not the same size. Water pump is 3/4" and heater core is 5/8". I've seen some people try to force a 5/8 hose over the 3/4 water pump nipple, many times splitting the hose; and I've seen people use a 3/4 hose and try to clamp it tight enough on the 5/8 core connection, of course resulting in persistent leaking. You can get an actual factory hose made for the application with different sizes at each end. The NAPA part # for the factory hose is 10084. But most people just buy generic hose from the auto parts store and slap it in there with adaptors somewhere in-line to connect the two different hose sizes, like in this pic.

10084.jpg adaptor.jpg adaptors.webp

adaptors.webp
 
I had same issue. I was using too big a clamp and was not squeezing hose around tube correctly. The right size fuel injection style clamp was my remedy.
 
Is it leaking around the core connection or the hose? If it’s leaking at the hose tightening should have stopped it. If you have a crackers weld - braze joint, that’s a whole burger issue.


Sent from my iPhone using Tapatalk
 
I had same issue. I was using too big a clamp and was not squeezing hose around tube correctly. The right size fuel injection style clamp was my remedy.
This is the way. I replaced both hose clamps with better quality ones that I can actually tighten down, and they hold and the leak stopped.

Now I get to look forward to whatever unexpected headaches will happen when I replace the carburetor and water pump next month. Major repairs are always an adventure with a CJ

Sent from my SM-A528B using Tapatalk
 

Jeep-CJ Donation Drive

Help support Jeep-CJ.com by making a contribution.

Help support Jeep-CJ.com by making a contribution.
Goal
$200.00
Earned
$0.00
This donation drive ends in
0 hours, 0 minutes, 0 seconds
  0.0%
Back
Top Bottom