Abstract: A single cylinder pump for circulating cleaning fluids through a radiator or like cooling system applies positive and negative pressure to the fluid to create a pulsating agitation of the fluid through the radiator through the use of a thin washer-like plate which is reciprocatively driven within the cylinder. The washer-like plate is slightly smaller than the cylinder and is separated from the inside of the cylinder by a small annular clearance thereby eliminating the need for lubrication and permitting the pump to be self-priming and to release gases generated by the agitation of the fluids.

Abstract: A sleeve is splined to but axially slidable on a shaft between two gears rotatable relative to said shaft and having fixed lugs on their inner faces. A clutch ring is journalled on each end of the sleeve and provided with clutch dogs engageable with the lugs of one gear when the sleeve and ring are moved toward that one gear. A selector ring slides axially on the sleeve and when moved in one axial direction toward one of the gears it first positively clutches the advancing clutch ring to the sleeve then moves the sleeve and clutch ring toward that one gear to engage the clutch dogs of the advancing ring with the lugs on the one gear. Thereafter, when the selector ring is moved in the other direction, it first releases the clutched ring from the sleeve then repeats the above described clutching in the other direction.

Abstract: Apparatus for cleaning a cooling system having inlet and outlet ports for circulating a cleaning fluid. A cleaning solution is supplied to one port of the cooling system with the other port thereof communicating with a discharge conduit. Positive pressure and a negative pressure are created alternately in the discharge conduit to cause the cleaning solution to flow in opposite directions. One check valve in the discharge conduit permits flow only in response to the creation of positive pressure and another check valve permits flow only in response to the creation of negative pressure.