A hanger for suspending a liner in a cased subterranean well comprises an elongated tubular body having ramp elements formed on its exterior and a plurality of peripherally spaced slip elements secured to a sleeve piston surrounding the lower end of the tubular body. Seals provided intermediate the piston and the tubular body define a first fluid pressure chamber. A clean fluid is supplied to the first pressure chamber through an axially extending passageway of restricted diameter provided in the wall of the tubular body and having an opening at its bottom end communicating with the first pressure chamber and at its top end communicating with a second pressure chamber defined by a tubing carried run-in tool detachably engaged with the liner hanger. The two pressure chambers and the restricted diameter passage are filled with clean fluid at the surface and pressure is applied to the clean fluid through an isolating piston mounted in the second fluid pressure chamber and actuated by non-clean fluids supplied through the tubular string upon which the run-in tool is suspended.