Both posts are true. Now if the cap breaks no worries. We realy do not need the heater. Many have removed the heater element all together and plugged the hole with RTV or JB Weld. Even in the coldest areas the fuel still wont jell without the heater. Factory idea was to turn on the key but not start the engine. Leave it that way for something like 7 minutes. Its supposed to warm up the fuel but really??? Many of the older 6.9 truck engines had the heater in the hard line from the lift pump to the filter head. They burned out and nobody knew it. So how useful were they. Lastly why put the heat on TOP of the fuel instead of the bottom. Heat raises no matter what hemisphere we live in.