Heating problems

[lXl Explorer lX]

Hey guys i dont know if i have a problem or this is normal. This is my first winter with my explorer i had the 91 in the summer and now with my 97 sport its the first real cold weather...Ive noticed that when i go to start my truck in the morning for work after about 15-20 min warming up im still frezzing my ass off theres no hot air coming from the vents, just cold. But when i keep my foot on the gas for about 20-30 sec it heats up but then drops when i let it off...Has anyone else had this or do i have a problem.
Jay

 

[jgilbs]

check your fluid levels. if this does not help, you may have to replace your thermostat

 

[ronbo256]

sounds like a thermostat stuck open (much better than one that's stuck closed) or low coolant. check this out ASAP, since driving it much without enough coolant will warp or crack heads, something you can do without I'm sure. It may be too late already, that's how I found out my heads were cracked on my '89 ranger, the heater quit first.