Engine oil

Actually, is that quarts? Gallons? Are you going by how much you poured in? The level on the dip stick?

All engines today use some oil between oil changes, and to address the numerous complaints of low oil level, the manufacturers no longer stamp "Add" and "Full" on their dip sticks. Now they use "Min" and "Max". As long as the level remains above the "Min" mark, you do not have to add any. Where a problem can occur is when someone changes the oil and puts in just enough to reach the "Min" mark. It can be expected to go below that in a few thousand miles.

Some people see the level just a fuzz below the "Max" mark and still think it needs to be that high, so they add, and they often add a full quart. The engineers planned for that by leaving a safety margin. Where the potential problem comes in is if the level is high enough, the rotating crankshaft can hit the oil and whip air into it. Air in the oil can compress, and that prevents the oil from isolating moving parts, (lubricating the engine bearings). Many years ago with the really tough 318's, 289's, and 283's, they could easily survive the momentary loss of oiling with no permanent damage or symptoms. Today we have quite a few engines that are nothing to be especially proud of, so I am hesitant to say nothing bad will happen.

When I was doing oil changes, rather than risk damaging a customer's engine, I would unscrew the new oil filter and drain it to remove too much oil. If that is not an option for you, a simple caution is to do only light-throttle acceleration until you see everything is okay. No squealing tires. No passing other vehicles unless it just cannot be avoided. And definitely no racing against my Dodge Hemi. Save that for when some of the oil is used up and the level drops. At lower rpm, even if the crankshaft hits the oil, it is just going to fling it up onto other parts including the cylinder walls. All engines already have a means built in to spray oil onto the cylinder walls. At worst, if there is too much extra oil on the walls, it can overload the piston rings, then you will see blue smoke out the tail pipe.

Watch for the "oil" light flickering on and for blue smoke from the tail pipe. If you do not see either of those, it is highly doubtful an extra quart will cause a problem.