Heater in Mazda b2200 not working Any ideas why?

Answer 1

I would recommend doing a coolant flush and replacing the thermostat.I would suggest replacing the upper and lower radiator hoses if over four years old as well.To flush the system first drain the old coolant out then replace the hoses and the thermostat housing is connected to the upper radiator hose.Fill the system with water and a prestone brand flush run for 20 minutes and check the fluid level with the radiator cap off to alloy the air to escape and then place the cap back on let idle with heat on fan on the highest setting.Drain the flush refill with just water do the same as above.Once you run just water thru the sytem drain it out.Now fill the system with one gallon regular antifreeze and top off with water to reach the 50/50 mix.I normally use one gallon antifreeze and add a little water to get my protection to -30 or 265 degrees for maximum results.Now if after you still have no heat it could be you need to replace the heater core itself due to it being corrorded or blocked.To do this job does required removing the dash (not difficult unless your first time).Try the flush and hoses and new thermostat.If after the simple task and still no heat the heater core is more than likely the problem and does require several hours to do.I know first hand I just did mine.Effective January 2010. Note I use a stant lever release style radiator cap which releaves the pressure on the radiator with out spewing out fluid and it goes to the overflow reservoir so you can open the cap with no overflow to check the level and not have a mess.Hope this book is not overwhelming.