What do you do if you had the cracked radiator the thermostat water pump and timing belt replaced on a 92 Protege but still do not have much heat?

One possibility is that the thermostat was replaced with one that opens at a higher temp than the old one. I would suggest driving with cardboard in front of your radiator, cause everybody's doing it, but that's how I cracked my radiator, and sent my cars cooling system straight to hell, so do it at your own risk.

Answer

Thermostat may be defective, is coolant level up? What is bled properly? Heater core may be partially plugged. I am assuming the the volume (force) of air coming at you is adequete and the temperature is just the problem. How often did you flush the cooling system while you owned it?

Answer

Sounds like an air lock in the cooling system. Rebleed the system ie. remove the rad cap and let the car idle for a half hour or so. You may see the temp gauge move around a bit, but just make sure it doesn't sky rocket and you will be fine. As well, check around the hose inlets on the engine side for bleeder screws. If any are found open them as they are vital for proper bleeding.Good luck.

Answer

The genuine Mazda thermostat for a 92 protege has a small valve and the normal large valve. It is made to keep the engine quite hot. Third party thermostats often make mazdas run cooler and provide less heat.