I recall reading in the manual for one of my family’s old cars that it shouldn’t be driven more than 10 hours at a time. Furthermore, after driving for longer than X hours, when one pulls into their parking spot, they should let the engine idle for ten minutes or so.
Questions: What does this idling do?
How long could I conceivably drive a car without anything bad happening (assuming I don’t crash)? I assume that the other parts might give out before the engine has problems.
Well, after about six hours, you’ll run out of fuel…
Aside from that, I think you can run an internal combustion engine pretty much indefinitely. After about 20,000 miles, the oil will probably be worn out. This is longer than you typical oil-change interval because the engine only has to be started from cold and run up to temperature once.
How about using synthetic oil?
I’ve never heard of any time limit on how long you can drive your car. It would probably be physically impossible to drive the car ten hours without stopping since you would run out of gas. As far as idling the engine, I would hazard a guess that the car was turbocharged, and many turbo cars recommend you do that. On older turbo cars where the turbo was not water cooled, if you didn’t do this the oil would “coke”, which means it would solidify into gunk, which would eventually spell doom for the turbo.
However, there are plenty of times that cars drive as much as twenty-four hours without stopping. There are twenty-four hour races where street-stock cars drive without stopping.
Idling an engine after running it continuously at higher rpms allows the engine to cool down more gradually. This puts less thermal stress on the engine parts. My riding mower has the same recommendation (but only recommends 30 seconds of idling).
As for how long an internal combustion engine can be run, they can run for probably a lot longer than you expect. There’s no real reason to shut down an engine for refueling, and you could even rig up an oil system that allowed the oil to be changed (in a feed and bleed type of procedure) without shutting down the engine.
I’ve seen diesel engines (for large generators and ships) run continuously for months.
Assume you have systems to replace and replenish gasoline, motor oil and transmission fluid as other posters alluded to.
Based on reading I’ve done about a few very high mileage vehicles, you’ll probably need the engine overhauled somewhere between 200,000 and 450,000 miles.
Your transmission will probably need show-stopping service somewhere between 80,000 and 300,000 miles.
If you have a manual transmission and can avoid changing gears, you might not wear out your tranny. On that I’m uncertain.
Your brake pads… not certain. Depends on how much you use them.
Come to think of it, your tires would probably go before 80,000 miles.
80000 miles / 45 MPH = 1777 Hours
1777 Hours / 24 Hours = 74 Days
So assuming you have those fancy-pants 80,000 mile tires and not too many hard stops or hard starts, I’d bet on 74 days. If you’re doing jackrabbit starts or emergency stops look for your transmission or brake pads to die well before 74 days.