1)make sure you have a new thermostat (as above)
2)also replace your radiator cap.
After replacing the above..
The MA70 has a poorly designed cooling circuit that allows air to become trapped inside the system. Most radiator places may not "burp" the system properly. Follow this tech-tip to diy.
Oh, and while you're playing with the cooling system, and if you really love your car heaps and love spending money on it, I'd replace the top and bottom radiator hoses as preventative maintenance, and replace the coolant with the red Toyota stuff.