Heater vs Cold Air confusion...New Thermastat

[RhainyC]

Greetings Ladies n Gents,

Ok, so my poor lil old bones, NEED a heater and defroster that work...We replaced the thermostat, figuring that was the culprit to the cold air blowing threw when the heater was *supposed* to be on...no luck. Temp gauge says it is still *colder* than Normal, barely lifting the gauge up into the very low normal range. Engine does get warm, I can hear the vent/doors moving and apparently slipping open...but still icy cold air.

So, is it more than likely the heater core gone bad? Or should I look for a different problem? And if it is the heater core, how easy/difficult is it to change one?

My truck is a '91 Ranger 4x4, 4.0L with A/C, 5spd Mazda trans and an XLT trim kit.

Thanks Bunches!
RhainyC

 

[Thumper113]

The temp gauges in these things aren't very accurate. Once the engine is warmed up, check both heater hoses out of the firewall. If they're both hot, it's probably not your heater core. If one is hot & the other is cool or lukewarm, your heater core is restricted.
If that's the case, it's real easy to replace on your year/model. Under the dash on the passenger side, a few screws hold the cover on, remove that cover you'll see it right there. I know you said the vent doors are moving but the temp door may not fully close or open. Hope that gives you an idea at least.

 

[RhainyC]

Thanks much Thumper! I was not looking forward to trying to bumble my way through winter without a real heater...and if the thing is easy to change, then I might just change it so I know that isn't the problem regardless.

As you said, gauges aren't real accurate, but I knew when the gauge didn't barely move, during the summer, with the air on...well, that it wasn't quite right in the heating/cooling system. But, I will say this, the truck never got overly heated...which leads me to believe it probably is the core...

Cheers,
RhainyC