A variable displacement lubricant pump coupled to and driven by an internal combustion engine for pumping pressurized lubricant to the engine, comprising: a pump rotor with radially slidable vanes rotating in a shiftable control ring, a pressure control system for controlling the discharge pressure of the pressurized lubricant, the control system comprising: a first pressure control chamber for pushing the control ring into high pumping volume direction, a first pressure conduit (82, 87) connecting a pump outlet port with the first control chamber, and a pressure control valve controlling the pressure in the first pressure control chamber, the pressure control valve comprising: a control plunger for opening and closing a control port in a cylinder wall of the control valve, whereby the control port is connected with an outlet port of the control chamber, an input pressure plunger being charged with the pump outlet pressure and being connected with the control plunger, a control spring preloading the control plunger into a closed position against the pump outlet pressure, and a preload control arrangement for controlling the preload of the control spring, the preload control arrangement comprising: a preload plunger axially moving in a preload cylinder and supporting the basis of the control spring, a preload cylinder inlet for providing pressurized lubricant into the preload cylinder, and a preload control valve for controlling the lubricant pressure in the preload cylinder characterized in that a preload cylinder outlet is provided which is connected to a lubricant tank by a preload control discharge conduit, whereby the preload control valve is provided in line with the preload control discharge conduit. a pump rotor with radially slidable vanes rotating in a shiftable control ring, a pressure control system for controlling the discharge pressure of the pressurized lubricant, the control system comprising: a first pressure control chamber for pushing the control ring into high pumping volume direction, a first pressure conduit (82, 87) connecting a pump outlet port with the first control chamber, and a pressure control valve controlling the pressure in the first pressure control chamber, the pressure control valve comprising: a control plunger for opening and closing a control port in a cylinder wall of the control valve, whereby the control port is connected with an outlet port of the control chamber, an input pressure plunger being charged with the pump outlet pressure and being connected with the control plunger, a control spring preloading the control plunger into a closed position against the pump outlet pressure, and a preload control arrangement for controlling the preload of the control spring, the preload control arrangement comprising: a preload plunger axially moving in a preload cylinder and supporting the basis of the control spring, a preload cylinder inlet for providing pressurized lubricant into the preload cylinder, and a preload control valve for controlling the lubricant pressure in the preload cylinder a first pressure control chamber for pushing the control ring into high pumping volume direction, a first pressure conduit (82, 87) connecting a pump outlet port with the first control chamber, and a pressure control valve controlling the pressure in the first pressure control chamber, the pressure control valve comprising: a control plunger for opening and closing a control port in a cylinder wall of the control valve, whereby the control port is connected with an outlet port of the control chamber, an input pressure plunger being charged with the pump outlet pressure and being connected with the control plunger, a control spring preloading the control plunger into a closed position against the pump outlet pressure, and a preload control arrangement for controlling the preload of the control spring, the preload control arrangement comprising: a preload plunger axially moving in a preload cylinder and supporting the basis of the control spring, a preload cylinder inlet for providing pressurized lubricant into the preload cylinder, and a preload control valve for controlling the lubricant pressure in the preload cylinder a control plunger for opening and closing a control port in a cylinder wall of the control valve, whereby the control port is connected with an outlet port of the control chamber, an input pressure plunger being charged with the pump outlet pressure and being connected with the control plunger, a control spring preloading the control plunger into a closed position against the pump outlet pressure, and a preload control arrangement for controlling the preload of the control spring, the preload control arrangement comprising: a preload plunger axially moving in a preload cylinder and supporting the basis of the control spring, a preload cylinder inlet for providing pressurized lubricant into the preload cylinder, and a preload control valve for controlling the lubricant pressure in the preload cylinder a preload plunger axially moving in a preload cylinder and supporting the basis of the control spring, a preload cylinder inlet for providing pressurized lubricant into the preload cylinder, and a preload control valve for controlling the lubricant pressure in the preload cylinder characterized in that a preload cylinder outlet is provided which is connected to a lubricant tank by a preload control discharge conduit, whereby the preload control valve is provided in line with the preload control discharge conduit.