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Boiler Stop Leak

I used a bottle of this once to stop a leak at a threaded connection on a new install. Actually, it was new copper going into an existing cast-iron tap. Anyway, it stopped the leak cold and I never had any more problem with it.

Somebody told me once that it's a good idea to pour a bottle of stop-leak into new installations, just in case. Is that true? Do you run the risk that it will gum up valves and flat plate heat exchangers, or some other system component? Would stop-leak be an acceptible way to stop a leak in a soldered joint, or just a sloppy plumbing & heating practice?


  • Heatmeister_2
    Heatmeister_2 Member Posts: 88
    Not me

    I put some in my leaking cast boiler as a band aid fix b/c I knew I was going to be getting a new boiler in the spring. I gummed up more than my leak. When I went to drain my boiler, it locked up my valve completely. I had to take the valve off to drain the boiler..........what a mess.

    To be used as "a last resort" or Band-aid fix. IMHO.
  • oil-2-4-6-gas
    oil-2-4-6-gas Member Posts: 641

    i use stop leak all the time--buys some time until the boiler can be replaced--it is in NO WAY a fix for bad plumbing --fix the leak --all new systems should be pressure tested before put in service and all leaks fixed--Period !!--- i have a few boilers that have had stop leak in them for years -(customer doen't feel the need to replace--its not leaking-) and i've had another 1 that i put it in worked for a short time --then the boiler was beyond repair-wouldn't hold pressure--and that was of course at the coldest time of year --boiler replaced on overtime T&M--ouch --couple of issues with stop leak --in boilers with coils --their output is reduced-bleeders get clogged,drains clog,pumps and check valves can clog and in 1 case THE RELIEF VALVE WAS PLUGGED --
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