When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I just received a replacement heater core from Paragon Reproductions yesterday - part number 5770.
It seemed like a good idea to test the core first before going through all the work of re-assembling the interior.
I used a 700 x 25c bicycle inner tube cut to a nice length to slip over each tube. Secured with a tie wrap on each.
The first attempt to pressurize the tube (I was aiming for 15psi) caused the unsupported tube to explode at 10psi.
So, repeat procedure on a new tube, fill a basin with water and pressure test the core at ~ 10psi.
The joint where the larger (3/4" I think) tube joined the core showed a lot of bubbles indicating a leak.
I just wanted to share this with you all - it's a lot of work to remove and replace a heater core in these cars. Best to test it before you put it all back together.
I also tested mine from Zip.
Simply applied air to one pipe with my rubber tipped blow gun(with my compressor turned way down)and my thumb over the other pipe while submerging it in a 5 gal bucket of water. No bubbles.
Update - I took the heater core to Greenwood Radiator and discussed with the owner my options:
1. Return the core and try again - would still have fitment problems with the tubes and cradle not lining up requiring some bending to make it fit.
2. Build a new core from components he can order. ~$200
3. Attach my end cap with tubes to the new core, and solve the problem with fit, and hopefully the leak. $60
I went with option 3 and here is the new core attached to my old tubes. He also pressure tested the core at 20psi for an hour with no leakage noted.
The core now fits in the housing great - and I don't have to stress the solder joints assembling it all.
What brand was the new heater core that didn't work? I just received a PSHC brand heater core and it isn't even within massaging range. Can anyone recommend a brand?
TSM model 0399081 - which is a 2.5" thick core for 68-77 is what I received and was told is the best one out there. I don't have experience with any others.
C3 Heater Core Test
