1996 GMC Yukon Owner's Manual - Page 89

Engine Exhaust Running Your Engine While You're Parked It's better not to park with the engine running. But if you ever have to, here are some things to know. Engine exhaust can kill. It contains the gas carbon monoxide (CO), which you can't see or smell. It can cause unconsciousness and death. You might have exhaust coming in if: Your exhaust system sounds strange ordifferent. Your vehicle gets rusty underneath. 0 Your vehicle was damaged in a collision. Your vehicle was damaged when driving over high points on the road orover road debris. Repairs weren't done correctly. Your vehicle or exhaust system had been modified improperly. If you ever suspect exhaustis coming into your vehicle: Drive it only with all the windows down to blow out any CO; and Have your vehicle fixed immediately. Idling the engine with the system control off air could allow dangerous exhaust into your vehicle (see the earlier Caution under "Engine Exhaust"). Also, idling in a closed-in place can let deadly carbon monoxide(CO) into your vehicle even if the fan switch at the highest setting. One is place this can happen a garage. Exhaust with is CO can come ineasily. NEVER park in a garage with the engine running. Another closed-in place can beblizzard. (See a "Blizzard" in the Index.) -- -- 2-25