B3000 heater issue

[jimgetman]

My 1996 b3000 heater suddenly is only half as hot. Any ideas?

 

[RonD]

Couple of things could be the issue, these are just general heater issues not specific to B3000

Check coolant level first, low level effects flow through heater core

Is engine temp gauge the same as it has always been?
If its running cooler than normal the thermostat may need to be replaced.
Outside air temp should have no effect or only a small effect on engine temp, that's what the thermostat is for, it sets the minimum operating temp for the engine, usually 200-220deg F.

With engine warmed up and heat control inside set to HOT, open the hood and feel both heater hoses, the IN hose should be hotter than the OUT hose, but the OUT hose should still be hot, if its only warm then heat control valve/cable may be broken or the core may be getting clogged up.

If the OUT hose is not hot but only warm:
Find the heat control valve and check it for full motion, open and close.

If it seems ok then drain some coolant out of the rad, to below heater hose level.
Remove heater hoses and back flush the core.
There are several you tube videos on how to back flush heater cores
Basically you use a garden hose on the OUT line to push any debris backwards and out the IN line.
You want the flow to be backwards of normal flow to push any debris out the way it came in.

You can fill the core with CLR and let it sit for awhile and then back flush again, repeat as you see fit.
You can see the flow and if you think it is still too low then core will need to be replaced.

If the OUT hose is almost as hot as IN then core is ok and heater duct door inside the dash could be stuck or not working, this is usually behind the glove box.

 

[EMB1230]

Agreed, this problem is not Mazda-specific at all. I'm not sure if Rangers have this problem too, but Vulcan powered Taurses have problems with the heater cores becoming clogged with rust, due to the Vulcan being an all-iron engine. Flushing out the heater core usually fixes it.

 

[PanamaExpat]

Easiest solution to all your heater problems. Move to the tropics.

 

[MazdaHawaii]

I live in the tropics and I need a heater for 2 reasons: 1 - because it does get cold.. 2 - because it's humid and the windows fog up and you need a defroster for the windshield. I have a 96' B3000 and I too have a problem with my heater - except mine doesn't get hot at all. I was told it may have to do with vacuum lines. Have not looked into it yet, so...

 

[fisherbear]

flush the system to remove rust... use one of the rust removing flush additives... make sure coolant level is proper... I replaced the hoses to mine... hot air when I need it no problem.