Exhaust smell in car/overheats sometimes when idle

I would look for the exhaust leak in the engine bay or the pipe close to the engine bay. The exhaust is filling up your engine bay and your blower motor is sucking it in by the hood/windshield. Check where the exhaust pipe connects to the engine manifold(s) and where the manifold connects to the engine head. If it's cold out you can usually see a leak when you first start up and the engine bay is cold. If not you can feel the hot exhaust excaping in most situations while it is running, caution don't touch the exhaust. How hot does the car get. Do you have a factory temp gauge. If it's just rising above the normal crusing temp while idling and not over heating I wouldn't worry. If it is rising quite abit above the normal temp and closer to your danger zone then it's a problem.