No, don't open the case!
Laptops are finicky and you can damage things just by opening it improperly.

1 - use canned air to blow out all the vents. DON'T use a vacuum or air compressor as they can damage components.
2 - check to make sure the fan is working
3 - only use the laptop on a hard surface. Preferably, get a laptop cooling pad that blows cooler air over it.

If this doesn't stop it, then you'll have to take it to a shop for service.

Good Luck!