How much is to much oil?

[dhirocz]

You need to keep the oil at the full line as much as possible. The ISX has oil control in the form of a windage tray in the bottom end of the engine, but understand that that oil can move...like walk up the front or back of the engine while you brake and accelerate...and can also be affected if that oil comes into continuous contact with rotating components. It would have to be pretty high to do that, but I have seen oil whipped by a spinning crankshaft to the point it got foamy...and oil full of air bubbles doesn't do a good job protecting bearings. I don't know how prone the ISX or any other heavy diesel engine is to this, the RPM does generally stay fairly low... I'm not willing to gamble with my equipment either.

Last time I changed my own, I ended up with a little over half a gallon too much in it. Forgot about the filter capacity. I carefully put it back into a jug and used it to top it off between oil changes, my oil stays pretty clean now so there was no need to waste it.

Will being a little over filled hurt it? IMO, not really. The crank sits pretty high in relation to the oil pan. But it's also too easy to pay attention to detail and drink an extra beer while the oil drains back to the pan and make sure it's right, too.