I am sorry to say that you are going to have to hack away at the plaster and find them or remove a section of plaster board. Turn the water off at the stop tap and either call a plumber or take photos and ask a Plumbing supplies counter for a possible fix.
Yes, of course as the majority of leaks are behind walls or in the floor
Is the water still leaking? If so was the original line disconnected?
Result is broken pipes, so symptoms are: 1) no Water at faucet 2) leaking water elsewhere.
Plumbers are people who earn a living dealing with pipes.
It is the water rushing through the pipes creating a pumping sound
If it runs continually, as you say, then it can only be the inlet water pipe or fitting, leaking.
Roof leaking, wall leaking, soffit leaking from ice buildup on roof. First thing would be to go into attic and see if there is any signs of water, if there are no signs of water that means it is coming from the outside wall .
Metal dector or just stat opening the walls
Its not bad as long as they are not leaking. Unfortunately polybutylene pipes have the best chance to start leaking at some point and it can be costly to repair.
I take it that you mean that it's leaking water and not exhaust gasses. If it's the body of the cooler pipe that's leaking, then you'll have to find a good stainless-steel welder to repair it, or get a replacement. But if it's just one of the pipes to it, then replace both pipes whilst you're at it.
The cast of Light Hearts and Leaking Pipes - 1920 includes: Zip Monberg Virginia Warwick
It may be the wastes that the plugs attach to which are leaking. Also look around the perimeter of the sink is it well siliconed and no holes? It can seep through there.
Maybe the water is condensation coming off of the roof? If there are water pipes nearby, is one leaking?