Mosfet Hot and smelling

Hi, A while back I had a problem very similar to what is described here, only with me it was both my heated bed, and my nozzle.
I put a fan on my MOSFETs, and the problem went away.

Today, I noticed a smell coming from my printer and investigated it.
The heated bed MOSFET was getting quite hot, and when it got hot enough, it started smelling bad.
This wasn't magic blue smoke smelling bad, but more like plastic getting a little too hot.

Should I replace my mosfet, or is there anything else I should try first

btw I'm running RAMPS 1.4.

I'm going to try removing the load, and seeing if the MOSFET still gets hot.

Suggestions are welcomed.

Thanks, Max Tepermeister