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.
What can be worse than changing a heater core...changing one, buttoning up the job, filling the surge tank, starting the care and seeing fluid on the passenger floor. Yea thats right the new heater core leaked. This time I am off to the Chevy dealer to get raped but get a GM version if available. What a crummy day.
Always the possibility it's one of the hoses - check them closely. If one or the other (but particularly the inlet) is leaking at the end, you might not see it in the engine compartment and it will go into the passenger compartment.
Sorry about how your job went. Sounds like one of mine.
I saw a tip once that you might use to check the new one before installing. You could take a tube, like a thin racing bike tire, cut the tube and use hose clamps at the connections, then pump up the tire to the 15 or so lbs that it will see in use. Because it is a simple tire, you can measure pressure easily. Then leave it overnight and see whether it still holds. I guess you could hold it underwater, too. Anyway, if you try it, let me know what worked as I never have.
I feel your pain
I put mine in a bucket of water, plugged one line and blew into the other. I saw no air bubbles, so I hope it's good and that I had enough lung pressure to really test it.