How do you fix a heater on a 1991 Mazda B2200?

Answer 1

Well that is broad question.First is thermostat working properly meaning the gauge registers a correct indication as it did in the past.Second if not I would suggest draining the system,replace the upper and lower hoses if over four years old(recommended by hose manuf,and myself) replace thermostat.Now add a coolant flush top of with water run the truck for at least 20 minutes heat on hottest setting,fan on high.I suggest placing cardboard directly in front of radiator this will speed up the process.Also leave the radiator cap of briefly this aleves the air bubbles and top of water.Once this is done,drain system fill with water only and do the same process.Now if after doing this and still little heat or no heat the issue is one of two things.Either the water pump is going bad or the heater core itself has a blockage and either may need to be replaced.If the issue is corrected fill with normal green antifreeze mix to 50/50 or I use one gallon antifreeze and top of with water for maximum protection.Normally the water pump will leak or make noisy like a bearing and if the pump is leaking in will be right under the crankshaft pulley.If the pump is leaking it does require removing the timing belt to replace( would change belt,tensioner while your at it).Start simple and also touch the heater core pipes right above the accerlerator pedal and see if they even get hot after doing the basic corrections being hoses,thermostat,and would suggest replace the radiator cap if way old,this can affect pressure and temperature.I use the pressure relief type rad cap sold like at advance auto,auto zone has a lever on top to pull to allow pressure to escape and open with out fluid coming out hot or cold.Hope this helps give some insight into what to expect on a simple or complicated fix.