A "leaking valve" refers to a valve that has a small opening or crack which causes a fluid or gas to escape from where it should be contained.
Sentences with «leaking valve»
I don't know a simple way of detecting leaking valves on a diesel, if that is what you mean. (mechanics.stackexchange.com)
it takes YEARS to refine the art of leaking valve cover gaskets consistently year after year, along with pan gaskets, oil stand gaskets. (autoguide.com)
Mainly when using a leak down tester, you'll be troubleshooting an issue with a head gasket, leaking valve seals, and bad piston rings. (mechanics.stackexchange.com)