[MetroMPG]

You should have a cover over that thing so you can't put your fingers inside! Or drop tools or rocks in it. And so mice can't set up nests.

A well regarded motor expert once told me the surefire way to know if your motor is getting too hot is whether it or objects near it occasionally burst into flame.

Also, he said to check the appearance of the brush leads. Are they a nice coppery colour? Or do they look blue/purple, like they've been subjected to high heat?