The Stovebolt Site Forums The Shop Area Interiors Round heater cores and repairs

I wanted a recirculating heater for the simplicity and the fact it is not needed much in my climate. I have had very poor luck with these heaters and have now spent enough money to buy a completely rebuilt fresh air heater.

I purchased 2 restored ebay heaters guaranteed not to leak. They both did soon after operating them. I had one repaired twice and the second one once. They were pressure tested by the shop doing the repairs each time. I even took them to a second shop for pressure testing after the first one starting leaking a second time. The were tested at 18 psi (I know that is too high!) and were not leaking even though the one leaked after installing it for the 3rd time. When they leaked, the leaking occurred at the seem between the cores and and the tanks. The shops I had repair/test these cores are long standing businesses with excellent reputations.

The heaters only leaked when the truck was up to full temperature and coolant had been flowing through them for a while. I have a valve to control flow. At first I thought it was due to pressure build up but the core sees the same pressure whether water flows through the core or not and I am only running a 4# functioning radiator cap.

The only explanation I can come up with is there is enough thermal expansion that the seam opens enough to allow a small leak. It has never been more than rapid drips. The shops both agreed the only real fix would be to completely disassemble the unit and re-solder the tanks to the cores. Neither place wanted to take that on. They said there was no guarantee and they didn't want to gamble with my money. I think they just didn't want to do the job.

I finally bit the bullet and purchased a replacement core and fan from the Brassworks. I posted about this in the general truck forum since I thought it might have general interest.

Chuck