Whirlpool AKP288/NA oven problem with cooker thermostat over heating

my oven is Heating too much, I set the thermostat to say 50 degrees and it keeps Heating and Heating until the oven cuts out on the safety I suspected it has the thermostat as all you have just changed the element, and I may have done some damage to the capillary tubeas per your phone call today I did not know how to send photo of stat with this message so will send by email attachment.if it will help to find replacement the ref. on stat is as follows81380671 09281T150 26431OC
John Wildish

Whenever you replace a fan oven element care needs to be taken to ensure you do not cause any damage to the capillary tube which is full of gas. The video tutorials below will guide you in replacing the thermostat, fan element and replacement bulb lamp on your Whirlpool AKP288/NA oven.