need help diagnosing potential problem (coolant related?)
 

I have a problem with my 99 Jeep Cherokee Limited 6cyl 4.0L ... when I turn the heater on, after a while, i smell antifreeze. Theres no wetness on the floorboards and I cant find leaks? A friend suggested it might be the heater core? During the last checkup/oilchange service antifreeze had to be added :( There appear to be no drips from where I park the vehicle. The temperature seems normal and it hasnt overheated.
Suggestions?

I havent ever had to take the jeep to any repair place because my husband did all the repair work on it in the past. I'm divorced now, so its no longer an option... and dont trust strangers to work on my jeep :( So, when I go to see a mechanic about it, I think I need to sound like I know what I'm talking about so he doesnt rip me off :s Also, so I can research it to try to figure out how much it will cost. If its something simple, I might be able to fix it myself.

Some heater cores will leak just enough to smell before they develop a bad leak! Check all of your hose clamps under the hood before you do anything else, also check the hoses for cracks and swelling. It's not impossible for clamps to loosen over time, and the smell of antifreeze to enter the interior when using the defrost setting- as defrost allows fresh air to enter the cab to help prevent fogging.

same thing happened to my wife's liberty and it ended up costing her hte motor becuse the radiator blew out on the highway. on her's, it was the passenger side of the radiator at the crimp from the plastic side (end tank) to the aluminum core (finned area). the crimp was bad from the factory is all we can figure and over hte 6 months she had it the seal pushed out slowly. she was smelling antifreeze the week before and we searched and searched but couldn't find anything. it was because it was down low and behind the fan shroud (black plastic cover on the engine side of the radiator) and never got to be bad enough to drip, it would just weep until it let go on the highway (5 hours from home and fried the motor because the gauge never registered a change in temp)

anyways, check the radiator also so your not having to replace your motor over something as crappy as a bad seam on a radiator.