1994 Explorer Heater Issue

[AV8R1988]

I just replaced my thermostat and it now heats up to operating temp. (198 Deg.) Except it still blows cold. It momentarily blew hot air yesterday but not since then. What it sounds like might be happening is some sort of heater door underneath the dash that isn't changing, opening or something when I turn the heater on and slide it to heat I hear some vacuum noise. Any suggestions?

 

[BrooklynBay]

Welcome to this forum! This is the famous blend door issue. Check # 36, and # 61 in my list of useful threads for more information.

 

[AV8R1988]

Explorer Heater Issue Update (Fixed)

I just replaced my thermostat and it now heats up to operating temp. (198 Deg.) Except it still blows cold. It momentarily blew hot air yesterday but not since then. What it sounds like might be happening is some sort of heater door underneath the dash that isn't changing, opening or something when I turn the heater on and slide it to heat I hear some vacuum noise. Any suggestions?

Ok ppl, I took care of my heater issue. It turns out it was the heater control valve underneath the hood was sticking. Nothing a little WD-40 didn't cure. Thx for the feedback anyway.

 

[BrooklynBay]

Thanks for the update!