With ever increasing technological advances in electronics, modern computer components continue to produce higher power densities that present a challenge to thermal management. A radial flat-plate oscillating heat pipe (RFP-OHP) heat spreader is investigated to study the effect of central heating on the heat transport capability in an OHP. The investigated OHP has dimensions of 100 mm × 100 mm × 2.5 mm with central heating using a 30 mm × 30 mm heater. Experimental results show that when heat is added to the center section of one side of the radial flat-plate OHP, and when heat is removed from the whole surface of another side of the heat pipe, the startup power for the oscillating motion increases. In addition, the spacer effect on the heat transport capability including the startup is investigated experimentally. The spacer added between the cooling block and OHP could lower the startup power for oscillatory motion. When compared to a copper slab of the same dimensions in the same test configuration, the temperature difference for the OHP with and without the additional copper spacer was reduced by a maximum of 46% and 25%, respectively, at a power input of 525 W and a heat flux of 58 W/cm2.