Why may a b2000 Mazda overheat?

Answer 1

Let's start simple first.If your thermostat is stuck closed coolant will not flow thru the engine,and cooling system.If yours is really old,and your heat is not working properly I would change this first.Next several things that should be considered in step 2 like have you flushed the radiator and cooling system in the last 3 years.3rd if no I would do this now and change your upper and lower radiator hoses if they are over 4 years old(a good practice and or recommended time).Next is your radiator cap super old,I would suggest replacing that at this time as well.Once you have flushed the system mixed your coolant to the 50/50 mix normally one gallon normal green antifreeze and use distilled water with this NOT tap water.Does your temp continue to rise up after this I would consider replacing the waterpump because it may be corroded internally and not pushing the coolant as needed.Last I would remove your oil cap and make sure you do not have a milkshake colored paste on the cap(bad sign for a headgasket failure),and checking the oil dipstick as well.There other things like a blocked up radiator or heater core even after flushing that will just be at the end of there life and need to be replaced.If after these checks and work consider the radiator and heater core need to be replaced,Unless the waterpump or headgasket are At Fault.Hope this explains things and I have done all these steps including replacing the rad,heater core,water pump.Good luck and most mazdas need new big items after 20 plus years in general if not maintained correctly.