Coolant odor in cab

I have a 99 4.3. The past few days I have noticed a strong coolant odor inside the cab of the truck after I drive it for a few minutes. There is no coolant in the oil and the appears to be no noticeable lowering of the coolant level. As well, There is no loss in power and the heater works fine, the engine temp stays at operating range without fluctuation. There are no leaks in the hoses that I can find either. I am stumped as to the cause and would apreciate any help.

Heater core maybe?

Yeah, it's the heater core.

Check the passenger side floor area. When a heater core breaks it will leak into the cab area on the passenger side.

yep, definitely the heater core....happened to my 94 a few years ago....your windows probably get foggy and filmy a little as well if the leak is bad enough.

Thanks, I will check it out. The windows have been getting foggy and the leak is getting worse. Does anyone know how difficult the heater core is to change? Thanks.

A few hours. Here is a link that may help:
http://www.sytyarchives.com/howto/viewarticle.php?article_name=heater_core.php&dir=climate_controls

If you decide to only loosen the dash and pull out the right side, dont let it hang there without support. It puts too much stress on the surface and it will will crack.

Thanks, I will check it out. The windows have been getting foggy and the leak is getting worse. Does anyone know how difficult the heater core is to change? Thanks.
I had the same problem with my 87 Ranger,wasnt real hard on it to change the core. Good luck

There have been numerous accounts of this type of problem. First, do you hear a "gurgling" sound coming from behind the dash? If you do now, or hear it later, it means your heater core is about to go. Within a month, the sound will cease, and your cab will fill up with that pleasant smelling steam. Some believe that the orange dex-cool radiatior coolant is the culprit since this is a case that has happened to very many people, but nothing is confirmed as far as I know. So if you hear a "gurgling" coming from your truck at any time, go ahead and buy a heater core...you'll need it soon.

The dash has come out completely and it is a pain in the butt.Disconnect the battery,you do not want the airbag blowing out.