Dryer would start, and get warm, but not keep warm.

First watched a youtube video on the process. Took off front cover. I'd already replaced a belt so I knew what to expect. Two screws holding the retaining plate on top of Coil Valves (both). One screw was a bit seized, so a bit of persuasion w/ the pliers was in order. There was no info on which way up, but luckily I noticed a bump on each valve, and two matching holes on the retaining plate. (Note to others trying this) Of course while re-assembling a dropped and temporarily lost a screw, then one of the machine screws that hold the front cover on, but other than my stupidity, and frustration that job was easy. The cycling thermostat I just got "just in case". I knew the main thermostat was working, but couldn't accurately check this one, so I got a spare and replaced it. I'm sure it was one of the valve coils as I'd read another user had an issue where the coil would work fine at first, but after it got hot would not work. After a cool down, it'd work fine again. So all in all, easy job.