What do you call hot? Do you have a temp gun? It looks like you're running 4S, is that right?

The Quark esc has a reputation for needing help keeping it cool. It looks like you don't have any heatsinking on it. It needs it. Fans are nice, but won't take the place of good heatsinking. As for the motor, get an accurate temp on it. I don't know for sure, but that motor may be a bit on the small side for your truck. I see that you're running those big tires and wheels on your truck. Those are hard to get turning. A 1515 may have been a better choice. How much does your truck weigh.