OK, I have a 96 Sunfire 2.2l, 2 door and after i start my car and it gets to about 110-120 degrees I start to smell hot coolant through my heater. This has started recently. Itruns a little warm at stop lights and such, but never over heats, and doesn't seem to be losing any coolant. I'm thinking small leak in the heater core. but what do I know. If this is the issue, how tough is it to replace. I have done them in other cars but never a j. Thanks All.

Well to see if the heater core is the issue u should remove the pass side floor mat and check for dampness and just a visual check for a leak inside the car.I would recom checking ur hoses if there over 4yrs old it's recomm to replace them regardless of appearance.I do the hose change to avoid the issue of hose failure and if its running a little warm at stops make sure ur fan comes on and if the thermostat is old,being u never changed it out I would recom doing so.Cooling issues vary and can be many things like the fan not working,or relay, waterpump leaking or going bad,hose leak,etc.These are a couple of things that are basic checks and as for the heater core replace I do not know how much time,work on the newer Js.Hope this helps and if I left anything off or I am incorrect may others add or correct this.

I would guess that its your heater core...Do you have heat? Turn it on and check it out. Usually if you smell it i would check heater core for leaks or cracked hoses and if not and no heat just replace the core would be my guess. If when heater is on watch for a mist coming out your heater vents

ugh, i pity anyone that has to replace a heater core on their j. what a freakin nightmare. 5 hours just to get to the damn thing, and i didn't even know how many more hours to put it all back together. you have to literally pull the dash out. I pulled mine, and its definitely bad, so i replaced it, and the thermostat, and guess what. turns out the water pump is bad too. what a fun weekend...lol