There are two main reasons why an electric Whirlpool oven will overheat: either the thermostat or the thermal fuse is defective. It is also possible that the temperature control needs to be re-calibrated.
The temperature of an electric Whirlpool oven is controlled by a sensor bulb that monitors the air temperature within the appliance; if the bulb is loose, it can also affect the temperature of the oven. If the thermostat itself is damaged or worn out, it will not react correctly to the air temperature feed by the bulb. If parts are worn out and need to be replaced, an engineer should be called.