I am about to undertake putting in a new heater core on my F-150 4.6 V8. I found a link from this site to mstaszew. He has good pics and detailed instructions. I just have one question; one of the first things he explains is to start the truck and then turn the a/c on. The next step is to disconnect the battery. Am I supposed to disconnect the battery while the truck is running. Sounds like a stupid question, but.......Thank you ahead of time for any information.

 

No shut it off (the truck engine)then disconnect the battery. Good luck