Hate to disagree with ya'all but he still has a cat that converts most of the CO and other harmful gases into harmless CO2 and H2O. So you will be fine even with the windows up. Crack um any how tho. Oh and long term the reduced back pressure will harm the engine valves. As the Bax as noted.
Won't damage the engine, but exhaust directly under the car may mean carbon monoxide comes into the passenger compartment, and that is one method by which people commit suicide by routing exhaust fumes into the cockpit and roll up the windows and suffocate. So roll down all the windows, and be careful what you are breathing.
If a car doesn't have exhaust means either it isn't running or it's electric. If it's burning a fuel and no exhaust is coming out then there is a blockage. The car will quickly be engulfed in smoke and you would get carbon monoxide poison if you continued to try to drive it.
Credit Card is the best as it's sturdy, Check would not last two seconds
Check. In winter however, I use my credit card as an ice scraper.
