Boiling phenomena in liquid helium Il (He II) and liquid helium I (He I) were experimentally investigated. The temperature oscillations during boiling in He II are the result of the propagation of the thermal boundary layer and/or the expansion of a vapor bubble to the location of the superconductor temperature sensor. The pressure oscillations are caused by the direct contact of liquid He Il with the higher-temperature heater surface. The pressure oscillations are very periodic, and there is a strong correlation between the temperature and the pressure oscillations. In the boiling of He I, bubbles detach from the heater surface and are detected by the superconductor temperature sensor. Ile I boiling is different from the boiling of He II in that there is no correlation between the temperature and the pressure oscillations.