Are you seeing any cracks or anything in the hoses or the radiator? The LIM gasket leaks on the inside, so you'll notice it in your oil, not on/under the motor. If you're seeing leaks from the hoses/radiator connections, then you'll definitely want to replace those. No biggie doing those - plenty of room to work with. As for it heating up quickly, you might have air in the system. Try bleeding the air out of the system.