Our Kenmore dryer heats up but only gets warm. We have to run it multiple times to dry clothes. Occasionally it gets hot but not every time. We replaced the heating element a few years ago.

I am not absolutely sure that this is the problem, but you could have a bad temperature selection switch. If it is bad, it won't let it get hot, or might keep it hot all the time. Just something to think about. The element is OK, otherwise it wouldn't heat at all. Best of luck.