HEAT

This seems like there are several things that might be going on here. The smell could be oil seeping from the valve cover, it is a common problem with this model at this age/mileage, have the valve cover gasket inspected for said seepage and replacement is of course at your descretion. The thermostat that controls the engine coolant temperature is also a common failure item on this car, it may also be setting a fault and could be turning on the check engine light (or not) It should be replaced as well as a coolant flush(which will happen when the Tstat is replaced anyway) The cost to repair can be calculated as follows, parts cost plus the labor: parts are the valve cover gasket(go to Realoem. Com and put in this part #11120030496) and the labor is 1.9 hours and the tstat is 1.5 hours and the tstat part number is 11537509227 plus the cost of the coolant, maybe $20 Is this what you need to move this issue forward? Let me know if not!