Technical Heater core leaking at tubes

Early 60’s F100, the heater core was trash so I replaced it with a cheapie new repop, hooked up the 5/8” heater hoses, tightened the hose clamps, but it seems almost like the inlet and outlet tubes are too small... or the hoses are too big. I keep getting water seeping out of the hose connection. I don’t want to crank too hard on the clamps because the tubes are soft as hell metal and they’ll bend or crimp easily. Any tricks that I could try to get a better seal around the tubes/hoses? Thanks

 

smaller hoses.

 

I'll ask a seemingly obvious question, but, did you trim the ends of the hoses?

I had a similar thing happen on my off-topic car when I didn't trim back the hose. They had stretched just a little bit from age and the "bump" on the hard line, and let water past. After I trimmed them back, it stopped the leak.

 

measure the diameter of the tubes. Probably 1/2". If the outlet tubes are brass, you may be able to expand the tubes slightly. The other option is to use 1/2" hoses and change the fittings on the other end.

 

Yeah that was my thought was that maybe the inlet and outlet tubes on the heater core are slightly smaller diameter, too small for the 5/8” hoses, but if I went with a 1/2” hose, how would I connect the other ends to the water pump? Wouldn’t the hose be too small for the engine side ports?

 

sweat a bushing onto the heater tubes to get to 5/8. Make them out of brass or dig through box store's plumbing supplys they will have something close.

 

You'll figger out somehow. Jack E/NJ

 

A little permitex might work (non hardening) if the hoses are the correct size

 

Swedge them if you can hold it.

 

Just ordered two of those reducers, gonna give that a try first. Thanks!

 

Maybe get the correct heater core? Lippy

 

I wonder if it’s for metric sized hoses? I had an issue like it recently on an OT vehicle. 1/2 in too small, 5/8th to big. Damned Chrysler product too.

 

Use new, resilient hoses and worm-drive hose clamps. Old hoses develop hardened pathways for fluid to pass.
I like the BMW/Euro-style clamps, not the cheapie auto store trash.

 

Take your old ones off and go to NAPA or any auto parts store. They make those nipples in 1/2" and 5/8" sizes
that will work. Bob

 

You can get tube expanders for small tubes. Then you always have it for making things fit each other.
https://thediyoutlet.com/products/7...uau5-NvPzmn3TG6ZYD5Hcep5HAOHLGPRoC8asQAvD_BwE

 

Not all water pumps have removable fittings. If they do, then change them out to smaller.
I hope you also put new hose on at the same time you put a heater core in? I've seen old hoses get enlarged over time from heat and pressure. So maybe yours are old?

 

So I took the hoses back off and checked the inlet and outlet tubes again, and there’s no way a 1/2” hose is gonna fit over them, so I guess it definitely takes a 5/8” hose since I assume there isn’t anything in between. I’m using brand new hoses, so they should be true to size and not stretched out or anything.
I just can’t figure out why I can’t seem to get a good tight seal and this thing still leaks out of both tubes. Maybe I’m being too gentle and I really just need to crank the clamps down tighter. Maybe I’ll try a coat of permatex on the ports.

 

if I have that problem, especially with distorted tubes, I coat the fittings with RTV, slide the hose on and let it set overnight, then install the clamps

 

I have been seeing a lot of replacement parts being metric
(O'Reillys Avance AutoZone).
Especially the replacement aluminum heater cores instead of Brass.
I have Used Good Quality commercial heat shrink, Remove hose , install heat shrink over Nipple , heat with Lighter / small torch . Then reinstall hose & clamp.,, & Most new worm scree clamps are Junk!!

 

Looks like you've narrowed it down to an odd size tube. I have seen silicone hose seep badly do to a poor cut. The hose has a string like reinforcement. If the hose is not cut clean and there are dangling strands that get pushed between the hose and tube coolant will wick out of the string strands. I doubt that is your problem, but thought I would throw it out just in case.
B

 

Cut two pieces of hose that just barely fits over the tubes, get it hot and spray WD-40 over it first.. Then slide the hose over top the the sleeved tubes, first get it hot then spray with WD-40 also..

 

Maybe try putting some heat shrink tube on the tubing to make it a wee bit larger.

Sent from my SM-T350 using The H.A.M.B. mobile app

 

Not too many things ruin a trip any worse than leaking water hoses and the resultant overheating. Fix it right so you don't have to worry about breaking down. Your wife or significant other will be happier. Again, as I suggested above, get a tube expander and you might even look into one of the small bead rollers to put a bead in the tube if needed. Cheaper to buy one of these than to hire a wrecker.

https://thediyoutlet.com/products/7...uau5-NvPzmn3TG6ZYD5Hcep5HAOHLGPRoC8asQAvD_BwE