I have this on another forum. Went on a short drive yesterday. Got home and forgot to turn the engine off. It idled on my drive for over 5 hours. Felt like a fool. Filled the tank and found that it used very little gas. What kind of damage could I have done with that long idle. Changed the oil 2 days ago with Mobile 1. The oil was clean looking.

 

I doubt you did any damage. With today's electric cooling fans and electronic engine controls, it shouldn't matter. Just take it out for a brisk drive.

 

I would let it idle for 8 hours next time.........Forgot to shut it off?

 

How drunk were you to forget to turn the engine off? As for the engine, it's perfectly fine.

 

Have you ever wondered how long a police car idles? Rarely do they turn them off once they leave the depot. When working a major wreck the car sits idling for hours on end to keep the light bars working. Otherwise, the battery would be dead. As long as the fans work correctly, it's fine. But just for a guess, it probably used 3.5 gallons of gas during that time.

 

Probably not good but i wouldn't loose sleep over it. It actually is worse for the transmission because of something to do with the converter pumping certain things etc etc, but you will know if it blew a line right away.

I work out of my trucks and especially when out of town leave it running most of the day.

I would worry more about what your neighbors think.