Appropriate oil

[19Walt93]

Oil doesn't need to be changed because it failed somehow, it needs to be changed because it gets polluted/diluted with moisture and combustion byproducts. The more it operates below normal temp, the harder you accelerate, the more short trips, the faster it gets polluted. If you do long highway drives it will stay clean longer than it would doing short trips around town.

 

[sgtsandman]

I’m a big believer in the six months oil change interval but I don’t do a lot of long distance driving, as in hours of driving to get somewhere. So I don’t usually meet the recommended miles interval for oil changes.

I could get away with just sticking to the recommended mileage but then I would have to keep track of it. It’s easier to just do it every April and October and not have to worry about it.

Now for mileage specific stuff, I do pay attention to that. Like transmission fluid changes, axle fluid changes. The same goes for the time specific stuff like coolant. They are big number items where math isn’t involved.

 

[MikeG]

In addition to the above, oil has additives for wear, friction, chemical buffers / corrosion prevention, etc. Some of those can get 'used up' even if the oil doesn't turn to sludge. But I don't know how long those last.

My dad ran engines on propane, both vehicles and small (ie. 5-10HP) motors on their construction trucks in the 1970s. He said it was amazing how much cleaner the oil stayed when engines ran on propane.

 

[sgtsandman]

You’ll be surprised how much cleaner the inside of an engine is running synthetic oil. Even the “cheap” oil package stuff. The cleanest I ever saw was when I was running Amsoil but that gets real expensive. The inside of the engine looked brand new. The oil package stuff isn’t as good but a heck of a lot easier on the wallet and more than meets the minimum spec.

 

[Dirtman]

Oil is slippery.